COMPOSITIONS COMPRISING VANCOMYCIN

This invention relates to aqueous solution compositions of vancomycin, in particular ready-to- dilute compositions which are storage stable, non-toxic, and have greater dosing flexibility and improved handling.

Background

Vancomycin is a glycopeptide antibiotic, consisting of a heptapeptide chain which forms a tricyclic ring system, with sugars attached. The N-terminal amino acid leucine is critical for antibacterial activity. Vancomycin is derived from the fungus Amycolatopsis orientalis (formally Nocardia orientalis). It is used to treat various infections that are caused by gram positive bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin is typically used in the form of its hydrochloride salt, with molecular weight of 1485.71 Da.

Vancomycin blocks the transpeptidase step of bacterial cell wall synthesis by preventing the synthesis of key polymers within the peptidoglycan layer. Vancomycin forms hydrogen bonds with the D-alanyl-D-alanine moieties of the N-acetylmuramic acid (NAM) and N- acetylglucosamine (NAG) peptides. This binding prevents the synthesis of NAM and NAG peptides that form the backbone strands of the bacterial cell wall.

Vancomycin can be administered either orally or intravenously, depending on specific circumstances. The invention disclosed herein is primarily concerned with intravenously administered vancomycin.

There are a number of vancomycin products for intravenous use that are lyophilised. These products require reconstitution followed by dilution into an intravenous (IV) solution bag and are therefore rather inconvenient to use.

There are three commercial liquid products on the market that comprise pre-mixed formulations of vancomycin formulated in IV solution bags and that can be administered directly: Vancomycin Injection, USP IV Frozen Premix (marketed by Baxter) and VancoREADY™ (marketed by Xellia). For the purpose of the present invention such premixed products filled into IV solution containers such as bags or bottles are referred to as “ready-to-administer” products. Baxter USP IV premix, formulated in the GALAXY plastic container is a frozen, premixed 100 mL, 150 mL, or 200 mL solution containing 500 mg, 750 mg, or 1 g vancomycin respectively as vancomycin hydrochloride. Each 100 mL of solution contains approximately 5 g of glucose or 0.9 g of sodium chloride. The pH of the solution has been adjusted with hydrochloric acid and/or sodium hydroxide. The product must be stored in a freezer capable of maintaining temperature at or below -20 °C. Thawed solutions have a pH in the range of 3.0 to 5.0. After thawing at room temperature (25 °C) or under refrigeration condition (5 °C), this solution is intended for intravenous use only. The need to store in frozen form and the need to thaw before use causes some limitations and inconvenience for medical workers.

VancoREADY™ exists as a liquid product and is supplied in a single dose premixed IV solution bag as a clear and colourless to light brown, sterile, preservative-free solution. It is available in 7 different doses from 500 mg - 2 g. Each 100 mL of solution contains 500 mg vancomycin hydrochloride, 1.8 mL PEG400, 1.36 g N-acetyl-D-alanine, 1.26 g L-lysine hydrochloride, at pH 5.0. Long term storage is at room temperature (25 °C) for 16 months in aluminium overwrap, after removal from overwrap it is still stable for a further 28 days at 25 °C. VancoReady™ carries a “black box” warning due to the excipients of N-acetyl-D-alanine and PEG400 which have been known to cause fetal malformations in animal reproductive studies, so this product is advised against for pregnant women.

Apart from the ready-to-administer products described above that typically comprise 5 mg/ml vancomycin hydrochloride, there is a need for liquid concentrated compositions of vancomycin that require dilution into the IV bag or bottle prior to use. The benefit of such concentrated product format over the pre-mixed ready-to-administer products is greater dosing flexibility to address different dosing regimens. For the purpose of the present invention such concentrated vancomycin compositions are referred to as “ready-to-dilute” products or “composition concentrates”. Optimally, a ready-to-dilute product comprises 50 mg/ml vancomycin hydrochloride.

The present invention addresses the need for stable and non-toxic vancomycin compositions, that are provided in ready-to-dilute form, thereby providing greater dosing flexibility and improved handling.

WO2014/194296A1 (SCI DOSE, LLC.) discloses compositions comprising vancomycin or a pharmaceutically acceptable salt thereof; a polar solvent such as propylene glycol, polyethylene glycol and mixtures thereof; lactic acid, a lactate salt, or mixtures thereof; and optionally, a pH adjuster in an amount sufficient to maintain a pH of the compositions at from about 3 to about 8.

WO2017/123912A1 (SCIDOSE, LLC.) discloses compositions comprising vancomycin or a pharmaceutically acceptable salt thereof, a polyol such as glycerol, and lactic acid or a lactate.

US2020/0188478A1 (FTF PHARMA PRIVATE LIMITED) discloses pre-mixed vancomycin compositions said to be suitable for injection.

JP2008/201778A (MOCHIDA PHARM CO LTD.) discloses vancomycin compositions said to be suitable for long-term storage and oral administration.

WO2017/194385A1 (XELLIA PHARMACEUTICALS APS) discloses liquid formulations of glycopeptide antibiotics such as vancomycin, which are said to be suitable as infusion solutions.

US2018/0133286A1 (XELLIA PHARMACEUTICALS APS) discloses compositions containing vancomycin, and an amino acid or amino acid derivative such as N-acetyl-glycine or N-acetyl- D-alanine.

Summary of the invention

The present invention provides, inter alia, a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration of 25-75 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof;

- a cosolvent selected from propylene glycol and a mixture of propylene glycol and glycerol; and

- an inorganic salt containing a metal cation.

Detailed description of the invention

In the compositions of the invention vancomycin may be present in the form of a pharmaceutically acceptable salt. Examples of pharmaceutically acceptable salts include hydrochloride, citrate, formate, acetate, tartrate, sulphate, tosylate, nitrate, mesylate, napsylate, besylate, oxalate, maleate, phosphate, pamoate, fumarate, hippurate, succinate and carbonate. In one embodiment, the vancomycin form is vancomycin hydrochloride. For the avoidance of doubt, any reference herein to “vancomycin” is also intended to cover a pharmaceutically acceptable salt of vancomycin, in particular the hydrochloride salt, unless stated otherwise.

Compositions of the present invention are “ready-to-dilute” compositions (and may also be described as a “composition concentrate”) containing vancomycin at a concentration which is higher than that required for administration (typically intravenous administration). The composition of the invention is therefore typically diluted to the required concentration shortly before the administration. Prior to use, the composition is typically stored in a suitable container such as a sealed vial. In one embodiment, the concentration of vancomycin or pharmaceutically acceptable salt thereof is 30-70 mg/mL, 35-65 mg/mL, 40-60 mg/mL or about 50 mg/mL.

As described in the background of invention, the currently marketed liquid vancomycin composition VancoReady™ contains N-acetyl-D-alanine (NADA) and PEG400 as excipients, both of which have been linked to fetal malformations in animal reproductive studies, therefore are to be avoided in this context. As described in present Example 3, the N-acetyl-D-alanine (NADA) in the VancoReady™ composition appears to provide a stabilizing effect. As described in Example 4, the present inventors have discovered that using D-lactate in place of NADA, a stable composition is formed. No stabilizing effect was observed when L-lactate was used in place of NADA. As shown in Examples 6 and 7, the racemic form of lactate (DL-lactate) also provides a stabilizing effect, but the concentration is typically twice as high as D-lactate to achieve a comparable stabilizing effect.

In one embodiment, the composition comprises a pharmaceutically acceptable salt of D-lactic acid (also referred to herein as “D-lactate”). Suitable pharmaceutically acceptable salts of D- lactic acid include sodium D-lactate, calcium D-lactate and potassium D-lactate. In one embodiment, the pharmaceutically acceptable salt of D-lactic acid is sodium D-lactate. In one embodiment, the concentration of D-lactic acid or a pharmaceutically acceptable salt thereof is 100-1000 mM, e.g. 200-1000 mM, 100-500 mM or 200-500 mM, and in particular is about 400-450 mM or about 400 mM or about 200 mM.

In one embodiment, the composition is substantially free of, or free of L-lactic acid and salts thereof i.e. the only form of lactic acid or lactate in the composition is D-lactic acid or a pharmaceutically acceptable salt thereof. In this embodiment, “substantially free of” means that less than 1 % of the molar concentration of total lactic acid (i.e. total molar concentration of D-lactic acid or salts thereof and L-lactic acid or salts thereof) is in the form of L-lactic acid or salts thereof e.g. for a composition comprising D-lactic acid or pharmaceutically acceptable salt thereof at a concentration of 500 mM, the composition will contain less than 5 mM of L- lactic acid or a salt thereof.

In one embodiment, the source of D-lactic acid or a pharmaceutically acceptable salt thereof is DL-lactic acid or a pharmaceutically acceptable salt thereof (also referred to herein as “DL- lactate”). Suitable pharmaceutically acceptable salts of DL-lactic acid include sodium DL- lactate, calcium DL-lactate and potassium DL-lactate. In one embodiment, the pharmaceutically acceptable salt of DL-lactic acid is sodium DL-lactate. In one embodiment, the concentration of DL-lactic acid or a pharmaceutically acceptable salt thereof is 200-1000 mM, e.g. 400-1000 mM, e.g. 500-1000 mM and in particular is about 800 mM or about 400- 450 mM or about 400 mM.

It should be noted that the pharmaceutically acceptable salt of D-lactate or DL-lactate can be formed in situ by adding D-lactic acid or DL-lactic acid to the composition and then adjusting the pH (e.g. by addition of a base such as NaOH) to form D-lactate or DL-lactate. It is expected that D-lactate added to the composition in the form of sodium D-lactate would have the same effect as the addition of the same quantity (molar) of lactic acid, with a subsequent pH adjustment step using sodium hydroxide.

As described above, it has been discovered that the currently marketed VancoReady™ composition can be modified to replace the stabilizer NADA with D-lactate, while maintaining a composition with good stability. As shown in Examples 4-7, the present inventors have also discovered that further modification of the D-lactate composition to replace PEG400 with propylene glycol or a mixture of propylene glycol and glycerol provides a surprising relative increase in stability.

Thus, in one embodiment, the composition of the invention comprises a cosolvent selected from propylene glycol and a mixture of propylene glycol and glycerol, wherein the cosolvent is present at a concentration of 5-50% (v/v), for example 10-50% (v/v), 15-50% (v/v), 20-50% (v/v), 25-50% (v/v), 30-50% (v/v), 35-50% (v/v), 5-40% (v/v), 10-40% (v/v), 15-40% (v/v), 20- 40% (v/v), 25-40% (v/v), 30-40% (v/v), 35-40% (v/v), 5-30% (v/v), 10-30% (v/v), 15-30% (v/v), 20-30% (v/v), 25-30% (v/v), 5-25% (v/v), 10-25% (v/v), 15-25% (v/v), 20-25% (v/v), 5-20% (v/v), 10-20% (v/v), 15-20% (v/v), about 35% (v/v), about 30% (v/v), about 25% (v/v), about 20% (v/v) or about 15% (v/v). In one embodiment, the composition of the invention comprises a cosolvent selected from propylene glycol and a mixture of propylene glycol and glycerol, wherein the cosolvent is present at a concentration of 5-50% (v/v), 10-50% (v/v), 10-40% (v/v), 10-30% (v/v) or 15-30% (v/v). The term “v/v” means “volume per volume” and is used to express the concentration of a liquid substance in the composition on a volume per volume basis. For example, 20% (v/v) of propylene glycol means that there is about 20 mL of propylene glycol in every 100 mL of the composition.

In one embodiment, the composition of the invention comprises propylene glycol as cosolvent, suitably at a concentration of 5-50% (v/v), for example 10-50% (v/v), 15-50% (v/v), 20-50% (v/v), 25-50% (v/v), 30-50% (v/v), 35-50% (v/v), 5-40% (v/v), 10-40% (v/v), 15-40% (v/v), 20- 40% (v/v), 25-40% (v/v), 30-40% (v/v), 35-40% (v/v), 5-30% (v/v), 10-30% (v/v), 15-30% (v/v), 20-30% (v/v), 25-30% (v/v), 5-25% (v/v), 10-25% (v/v), 15-25% (v/v), 20-25% (v/v), 5-20% (v/v), 10-20% (v/v), 15-20% (v/v), about 50% (v/v), about 45% (v/v), about 40% (v/v), about 35% (v/v), about 30% (v/v), about 25% (v/v), about 20% (v/v) or about 15% (v/v). In one embodiment, the composition of the invention comprises propylene glycol as cosolvent, at a concentration of 5-50% (v/v), for example 10-50% (v/v), 10-40% (v/v), 10-30% (v/v), 15-30% (v/v), about 20% (v/v) or about 25% (v/v). In one embodiment, the composition of the invention comprises propylene glycol as cosolvent, at a concentration of 5-25% (v/v), for example 5- 20% (v/v), 10-20% (v/v), about 20% (v/v) or about 15% (v/v). In this embodiment, the composition does not contain glycerol.

In one embodiment, the composition of the invention comprises a mixture of propylene glycol and glycerol as cosolvent, suitably at a combined total concentration of 5-50% (v/v), for example 10-50% (v/v), 15-50% (v/v), 20-50% (v/v), 25-50% (v/v), 30-50% (v/v), 35-50% (v/v), 5-40% (v/v), 10-40% (v/v), 15-40% (v/v), 20-40% (v/v), 25-40% (v/v), 30-40% (v/v), 35-40% (v/v), 5-30% (v/v), 10-30% (v/v), 15-30% (v/v), 20-30% (v/v), 25-30% (v/v), 5-25% (v/v), 10- 25% (v/v), 15-25% (v/v), 20-25% (v/v), 5-20% (v/v), 10-20% (v/v), 15-20% (v/v), about 50% (v/v), about 45% (v/v), about 40% (v/v), about 35% (v/v), about 30% (v/v), about 25% (v/v), about 20% (v/v) or about 15% (v/v). In one embodiment, the composition of the invention comprises a mixture of propylene glycol and glycerol as cosolvent, at a combined total concentration of 5-50% (v/v), for example 10-50% (v/v), 10-40% (v/v), 10-30% (v/v), 15-30% (v/v) about 25 % (v/v) or about 50% (v/v).

In one embodiment, the composition of the invention comprises a cosolvent which is a mixture of propylene glycol and glycerol, wherein the propylene glycol is present at a concentration of 2-25% (v/v), for example 5-25% (v/v), 10-25% (v/v), 15-25% (v/v), 20-25% (v/v), 2-20% (v/v), 5-20% (v/v), 10-20% (v/v), 15-20% (v/v), 2-15% (v/v), 5-15% (v/v), 10-15% (v/v), 2-10% (v/v), 5-10% (v/v), about 10% (v/v) or about 15% (v/v) (in particular 2-25% (v/v), 5-25% (v/v), 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v)); and the glycerol is present at a concentration of 2-45% (v/v), for example 5-45% (v/v), 10-45% (v/v), 15-45% (v/v), 20-45% (v/v), 25-45% (v/v), 30-45% (v/v), 35-45% (v/v), 40-45% (v/v), 2-40% (v/v), 5- 40% (v/v), 10-40% (v/v), 15-40% (v/v), 20-40% (v/v), 25-40% (v/v), 30-40% (v/v), 35-40% (v/v), 2-35% (v/v), 5-35% (v/v), 10-35% (v/v), 15-35% (v/v), 20-35% (v/v), 25-35% (v/v), 30-35% (v/v), 2-30% (v/v), 5-30% (v/v), 10-30% (v/v), 15-30% (v/v), 20-30% (v/v), 25-30% (v/v), 2-25% (v/v), 5-25% (v/v), 10-25% (v/v), 15-25% (v/v), 20-25% (v/v), 2-20% (v/v), 5-20% (v/v), 10-20% (v/v), 15-20% (v/v), 2-15% (v/v), 5-15% (v/v), 10-15% (v/v), 2-10% (v/v), 5-10% (v/v), 2-5% (v/v), about 10% (v/v), about 15% (v/v), about 20% (v/v) or about 35% (v/v) (in particular 2- 45% (v/v), 5-40% (v/v), 5-35% (v/v), about 10% (v/v) or about 35% (v/v)). In this embodiment, suitably the combined total concentration of propylene glycol and glycerol as cosolvent is 5- 50% (v/v), 10-50% (v/v), 15-50% (v/v), 20-50% (v/v), 25-50% (v/v), 30-50% (v/v), 35-50% (v/v), 5-40% (v/v), 10-40% (v/v), 15-40% (v/v), 20-40% (v/v), 25-40% (v/v), 30-40% (v/v), 35-40% (v/v), 5-30% (v/v), 10-30% (v/v), 15-30% (v/v), 20-30% (v/v), 25-30% (v/v), 5-25% (v/v), 10- 25% (v/v), 15-25% (v/v), 20-25% (v/v), 5-20% (v/v), 10-20% (v/v), 15-20% (v/v), about 50% (v/v), about 45% (v/v), about 40% (v/v), about 35% (v/v), about 30% (v/v), about 25% (v/v), about 20% (v/v) or about 15% (v/v) (in particular 5-50% (v/v), 10-50% (v/v), 10-40% (v/v), 10- 30% (v/v), 15-30% (v/v), about 25 % (v/v) or about 50% (v/v)).

In one embodiment, the composition comprises a mixture of propylene glycol and glycerol as cosolvent, wherein the concentration of propylene glycol is 2-25% (v/v), for example 5-25% (v/v), 10-25% (v/v), 15-25% (v/v), 20-25% (v/v), 2-20% (v/v), 5-20% (v/v), 10-20% (v/v), 15- 20% (v/v), 2-15% (v/v), 5-15% (v/v), 10-15% (v/v), 2-10% (v/v), 5-10% (v/v), about 10% (v/v) or about 15% (v/v) (in particular 2-25% (v/v), 5-25% (v/v), 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v)); and the concentration of glycerol is 35-45% (v/v), for example 40-45% (v/v), 35-40% (v/v), about 35% (v/v) or about 40% (v/v). In this embodiment, suitably the combined total concentration of propylene glycol and glycerol as cosolvent is 40-50% (v/v) e.g. 45-50% (v/v), about 45% (v/v) or about 50% (v/v). In one embodiment, the ratio (v/v) of propylene glycol to glycerol is between 1 :3 and 1 :1.5.

In one embodiment, the composition comprises a mixture of propylene glycol and glycerol as cosolvent, wherein the concentration of propylene glycol is about 10% (v/v) and the concentration of glycerol is about 35% (v/v), or wherein the concentration of propylene glycol is about 15% (v/v) and the concentration of glycerol is about 35% (v/v). In one embodiment, the composition comprises a mixture of propylene glycol and glycerol as cosolvent, wherein the concentration of propylene glycol is 2-25% (v/v), for example 5-25% (v/v), 10-25% (v/v), 15-25% (v/v), 20-35% (v/v), 2-20% (v/v), 5-20% (v/v), 10-20% (v/v), 15- 20% (v/v), 2-15% (v/v), 5-15% (v/v), 10-15% (v/v), 2-10% (v/v), 5-10% (v/v), about 10% (v/v) or about 15% (v/v) (in particular 2-25% (v/v), 5-25% (v/v), 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v)); and the concentration of glycerol is 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v). In this embodiment, suitably the combined total concentration of propylene glycol and glycerol as cosolvent is 5-40% (v/v) e.g. 10-40% (v/v), 15-40% (v/v), 20-40% (v/v), 25-40% (v/v), 30-40% (v/v), 35-40% (v/v), 5-30% (v/v/), 10- 30% (v/v), 15-30% (v/v), 20-30% (v/v), 25-30% (v/v), 5-25% (v/v), 10-25% (v/v), 15-25% (v/v), 20-25% (v/v), 5-20% (v/v), 10-20% (v/v), 15-20% (v/v), about 40% (v/v), about 35% (v/v), about 30% (v/v), about 25% (v/v), about 20% (v/v) or about 15% (v/v) (in particular 5-40% (v/v), 10- 30% (v/v) or about 25% v/v)). In one embodiment, the ratio (v/v) of propylene glycol to glycerol is between 2:1 and 1.2:1.

In one embodiment, the composition comprises a mixture of propylene glycol and glycerol as cosolvent, wherein the concentration of propylene glycol is about 15% (v/v) and the concentration of glycerol is about 10% (v/v).

In one embodiment, the molar ratio of vancomycin or a pharmaceutically acceptable salt thereof, to cosolvent (i.e. propylene glycol or a mixture of propylene glycol and glycerol), is between 1 :10 and 1 :100, e.g. between 1 :20 and 1 :60.

In one embodiment, the osmolarity of the composition is 1500-8000 mOsm/L, such as 2000- 6000 mOsm/L, such as 3000-6000 mOsm/L.

For the avoidance of doubt, any reference herein to “osmolarity” refers to a calculated osmolarity. Osmolarity is calculated as the sum of the molarities of all individual species dissolved in the solution and is expressed as osmoles per litre (Osm/L) or milliosmoles per litre (mOsm/L). For species that do not dissociate in the solution, the osmolarity (in Osm/L or mOsm/L) is equal to molarity (in moles/L or mmoles/L). For example, 500 mM glycerol in a solution at pH 5.0 does not dissociate, such that the solution has an osmolarity of 500 mOsm/L. For species that do dissociate in the solution, the osmolarity is the sum of the molarities of all dissociated species. For example, 500 mM sodium chloride at pH 5.0 dissociates into 500 mM sodium cation and 500 mM chloride anion, such that the solution has an osmolarity of 1000 mOsm/L. The composition of the invention is an aqueous solution composition and comprises at least 95% (v/v) of water, such as at least 90% (v/v), at least 85% (v/v), at least 80% (v/v), at least 75% (v/v), at least 70% (v/v), at least 65% (v/v), at least 60% (v/v), at least 55% (v/v) or at least 50% (v/v) of water, e.g. sterile water for injection or bacteriostatic water for injection.

Compositions of the invention contain an inorganic salt containing a metal cation. As shown in Examples 5-8, the salt provides a stabilizing effect. In one embodiment, the composition further comprises an inorganic salt containing a Group 1 or Group 2 metal cation. In one embodiment, the inorganic salt containing a metal cation is selected from the group consisting of sodium chloride, calcium chloride, sodium oxamate and sodium sulphate. In one embodiment, the inorganic salt containing a metal cation is sodium oxamate. In one embodiment, the inorganic salt containing a metal cation is sodium chloride or calcium chloride, in particular sodium chloride. The concentration of inorganic salt containing a metal cation is typically 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM or about 200 mM. The aforementioned concentrations of inorganic salt will typically represent the concentration of inorganic salt such as sodium chloride added to the composition.

The effect of pH on the stability of vancomycin compositions is shown in Example 2, where a range of pH values between 3.5 and 9.5 were tested, with the optimal pH being observed to be between 4.5 and 5.5. Thus, in one embodiment, the pH of the composition of the invention is in the range 4.0 to 6.0, such as about 5.0.

It should be noted that all references herein to “pH” refer to the pH of a composition evaluated at 21 °C. All references to “pK _a ” refer to the pK _a of an ionisable group evaluated at 25 °C (see CRC Handbook of Chemistry and Physics, 79 ^th Edition, 1998, D. R. Lide).

In one embodiment, the composition further comprises an antioxidant, which is suitably selected from the group consisting of monothioglycerol, butylated hydroxyanisole, glutathione (reduced), ascorbate, cysteine and methionine, and is suitably methionine. When included, the antioxidant is typically present in the composition at a concentration of 1-100 mM, e.g. IQ- 50 mM or 25-50 mM.

In one embodiment, the composition of the invention is substantially free of, or free of amino acids. In one embodiment, the composition of the invention is substantially free of, or free of polyethylene glycol (PEG), in particular PEG400. In one embodiment, the composition of the invention is substantially free of, or free of glycerol. In one embodiment, the composition of the invention is substantially free of, or free of N-acetyl-D-alanine. In one embodiment, the composition of the invention is substantially free of, or free of ethanol. In one embodiment, the composition of the invention is substantially free of, or free of EDTA. In one embodiment, the composition of the invention is substantially free of, or free of cyclodextrins, e.g. sulfobutylether-betacycoldextrin. In all of these embodiments, “substantially free of” means that the composition contains less than 0.1 mM of the stated component.

The composition may comprise a non-ionic surfactant, which is suitably selected from the group consisting of an alkyl glycoside, a polysorbate, an alkyl ether of polyethylene glycol, a block copolymer of polyethylene glycol and polypropylene glycol, and an alkylphenyl ether of polyethylene glycol.

When the non-ionic surfactant is an alkyl glycoside, it is suitably selected from the group consisting of dodecyl maltoside, dodecyl glucoside, octyl glucoside, octyl maltoside, decyl glucoside, decyl maltoside, decyl glucopyranoside, tridecyl glucoside, tridecyl maltoside, tetradecyl glucoside, tetradecyl maltoside, hexadecyl glucoside, hexadecyl maltoside, sucrose monooctanoate, sucrose monodecanoate, sucrose monododecanoate, sucrose monotridecanoate, sucrose monotetradecanoate and sucrose monohexadecanoate. In one embodiment, the alkyl glycoside is dodecyl maltoside or decyl glucopyranoside, and in particular is dodecyl maltoside.

When the non-ionic surfactant is a polysorbate, it is suitably selected from the group consisting of polysorbate 20, polysorbate 40, polysorbate 60 and polysorbate 80. In one embodiment, the non-ionic surfactant is polysorbate 20 or polysorbate 80. Polysorbates are known under a range of brand names including in particular Tween “XX”, and also Alkest TW “XX”, where “XX” is 20, 40, 60 or 80.

When the non-ionic surfactant is an alkyl ether of polyethylene glycol, it is suitably selected from the group consisting of polyethylene glycol (2) hexadecyl ether (Brij 52), polyethylene glycol (2) oleyl ether (Brij 93), polyethylene glycol (2) dodecyl ether (Brij L4), polyethylene glycol (4) lauryl ether (Brij 30), polyethylene glycol (10) lauryl ether (Brij 35), polyethylene glycol (20) hexadecyl ether (Brij 58) and polyethylene glycol (10) stearyl ether (Brij 78).

When the non-ionic surfactant is a block copolymer of polyethylene glycol and polypropylene glycol, it is suitably selected from the group consisting of poloxamer 188, poloxamer 407, poloxamer 171 or poloxamer 185. Poloxamers are also known under brand names Pluronics or Koliphors. For example, poloxamer 188 is marketed as Pluronic F-68. When the non-ionic surfactant is an alkylphenyl ether of polyethylene glycol, it is suitably 4- (1 ,1 ,3,3-tetramethylbutyl)phenyl-polyethylene glycol, also known under a brand name Triton X-100.

When included, the concentration of non-ionic surfactant is typically in the range 1-5000 pg/mL, 1-1000 pg/mL, such as 5-500 pg/mL, 10-400 pg/mL, 20-400 pg/mL, 50-400 pg/mL, 10-300 pg/mL, 20-300 pg/mL, 50-300 pg/mL, 10-200 pg/mL, 20-200 pg/mL, 50-200 pg/mL, 10-100 pg/mL, 20-100 pg/mL, 50-100 pg/mL or around 50 pg/mL.

The composition of the invention may additionally comprise a preservative such as a phenolic or benzylic preservative. The preservative is suitably selected from the group consisting of phenol, m-cresol, chlorocresol, benzyl alcohol, propyl paraben and methyl paraben, in particular phenol, m-cresol and benzyl alcohol, and mixtures thereof. When included, the concentration of preservative (total concentration when more than one preservative is present) is typically 10-100 mM, for example 20-80 mM, such as 25-50 mM. The optimal concentration of the preservative in the composition is selected to ensure the composition passes the Pharmacopoeia Antimicrobial Effectiveness Test (USP <51 >, Vol. 32).

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM, or DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

- propylene glycol as cosolvent, at a concentration of 5-25% (v/v), for example 5-20% (v/v), 10-20% (v/v), about 20% (v/v) or about 15% (v/v); and

- an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0. li In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM, or DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

- a mixture of propylene glycol and glycerol as cosolvent, wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v)) and the glycerol is present at a concentration of 35-45% (v/v), for example 40-45% (v/v), 35-40% (v/v), about 35% (v/v) or about 40% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 40- 50% (v/v) e.g. 45-50% (v/v), about 45% (v/v) or about 50% (v/v); and

- an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM, or DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

- a mixture of propylene glycol and glycerol as cosolvent, wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v)) and the glycerol is present at a concentration of 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 5-40% (v/v), 10-30% (v/v) or about 25% (v/v); and - an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM;

- propylene glycol as cosolvent at a concentration of 5-25% (v/v), for example 5-20% (v/v), 10- 20% (v/v), about 20% (v/v) or about 15% (v/v); and

- an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

- propylene glycol as cosolvent at a concentration of 5-25% (v/v), for example 5-20% (v/v), 10- 20% (v/v), about 20% (v/v) or about 15% (v/v); and

- an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0. In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v)) and the glycerol is present at a concentration of 35-45% (v/v), for example 40-45% (v/v), 35-40% (v/v), about 35% (v/v) or about 40% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 40- 50% (v/v) e.g. 45-50% (v/v), about 45% (v/v) or about 50% (v/v); and

- an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- DL lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v)) and the glycerol is present at a concentration of 35-45% (v/v), for example 40-45% (v/v), 35-40% (v/v), about 35% (v/v) or about 40% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 40- 50% (v/v) e.g. 45-50% (v/v), about 45% (v/v) or about 50% (v/v); and

- an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0. In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 5-40% (v/v), 10-30% (v/v) or about 25% (v/v); and

- an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 5-40% (v/v), 10-30% (v/v) or about 25% (v/v); and

- sodium chloride at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0. In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, e.g. vancomycin hydrochloride, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, e.g. sodium D-lactate, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 5-40% (v/v), 10-30% (v/v) or about 25% (v/v); and

- sodium chloride at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0; and wherein the osmolarity of the composition is 1500-8000 mOsm/L, e.g. 2000-6000 mOsm/L, or 3000-6000 mOsm/L.

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, e.g. vancomycin hydrochloride, at a concentration of about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, e.g. sodium D-lactate, at a concentration of 200-500 mM, e.g. about 400-450 mM or about 400 mM or about 200 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of about 15% (v/v) and the glycerol is present at a concentration of about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably about 25% (v/v); and

- sodium chloride at a concentration of 100-200 mM e.g. about 150 mM; wherein the pH of the composition is in the range 4.0 to 6.0; and wherein the osmolarity of the composition is 3000-6000 mOsm/L.

In one embodiment, there is provided a storage stable aqueous solution composition comprising: - vancomycin or a pharmaceutically acceptable salt thereof, e.g. vancomycin hydrochloride, at a concentration of about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, e.g. sodium D-lactate, at a concentration of about 400-450 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of about 15% (v/v) and the glycerol is present at a concentration of about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably about 25% (v/v); and

- sodium chloride at a concentration of 100-200 mM e.g. about 150 mM; wherein the pH of the composition is in the range 4.0 to 6.0; and wherein the osmolarity of the composition is 3000-6000 mOsm/L.

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, e.g. vancomycin hydrochloride, at a concentration of about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, e.g. sodium D-lactate, at a concentration of about 200 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of about 15% (v/v) and the glycerol is present at a concentration of about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably about 25% (v/v); and

- sodium chloride at a concentration of 100-200 mM e.g. about 150 mM; wherein the pH of the composition is in the range 4.0 to 6.0; and wherein the osmolarity of the composition is 3000-6000 mOsm/L.

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- DL lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 5-40% (v/v), 10-30% (v/v) or about 25% (v/v); and

- an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- DL lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 5-40% (v/v), 10-30% (v/v) or about 25% (v/v); and

- sodium chloride at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, or about 75 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, e.g. vancomycin hydrochloride, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- DL lactic acid or a pharmaceutically acceptable salt thereof, e.g. sodium DL-lactate, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 5-40% (v/v), 10-30% (v/v) or about 25% (v/v); and

- sodium chloride at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, or about 75 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0; and wherein the osmolarity of the composition is 1500-8000 mOsm/L, e.g. 2000-6000 mOsm/L, or 3000-6000 mOsm/L.

In one embodiment, there is provided a storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, e.g. vancomycin hydrochloride, at a concentration of about 50 mg/mL;

- DL lactic acid or a pharmaceutically acceptable salt thereof, e.g. sodium DL-lactate, at a concentration of about 400-450 mM;

- a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of about 15% (v/v) and the glycerol is present at a concentration of about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably about 25% (v/v); and

- sodium chloride at a concentration of 50-100 mM e.g. about 75 mM; wherein the pH of the composition is in the range 4.0 to 6.0; and wherein the osmolarity of the composition is 3000-6000 mOsm/L.

In one embodiment, there is provided a storage stable aqueous solution composition consisting of, or consisting essentially of:

(i) vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

(ii) D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM, or DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

(iii) propylene glycol as cosolvent at a concentration of 5-25% (v/v), 5-20% (v/v), 10-20% (v/v), about 20% (v/v) or about 15% (v/v);

(iv) an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; (v) water, e.g. water for injection;

(vi) optionally an antioxidant;

(vii) optionally a non-ionic surfactant; and

(viii) optionally a preservative; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition consisting of, or consisting essentially of:

(i) vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

(ii) D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM, or DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

(iii) a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 35-45% (v/v), for example 40-45% (v/v), 35-40% (v/v), about 35% (v/v) or about 40% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 40- 50% (v/v) e.g. 45-50% (v/v), about 45% (v/v) or about 50% (v/v);

(iv) an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM;

(v) water, e.g. water for injection;

(vi) optionally an antioxidant;

(vii) optionally a non-ionic surfactant; and

(viii) optionally a preservative; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition consisting of, or consisting essentially of:

(i) vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

(ii) D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM, or DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

(iii) a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 5-40% (v/v), 10-30% (v/v) or about 25% (v/v);

(iv) an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM;

(v) water, e.g. water for injection;

(vi) optionally an antioxidant;

(vii) optionally a non-ionic surfactant; and

(viii) optionally a preservative; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition consisting of, or consisting essentially of:

(i) vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

(ii) D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM;

(iii) propylene glycol as cosolvent at a concentration of 5-25% (v/v), for example 5-20%(v/v), 10-20% (v/v), about 20% (v/v) or about 15% (v/v);

(iv) an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM;

(v) water, e.g. water for injection;

(vi) optionally an antioxidant;

(vii) optionally a non-ionic surfactant; and

(viii) optionally a preservative; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0. In one embodiment, there is provided a storage stable aqueous solution composition consisting of, or consisting essentially of:

(i) vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

(ii) DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

(iii) propylene glycol as cosolvent at a concentration of 5-25% (v/v), for example 5-20% (v/v), 10-20% (v/v), about 20% (v/v) or about 15% (v/v);

(iv) an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM;

(v) water, e.g. water for injection;

(vi) optionally an antioxidant;

(vii) optionally a non-ionic surfactant; and

(viii) optionally a preservative; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition consisting of, or consisting essentially of:

(i) vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

(ii) D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM;

(iii) a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 35-45% (v/v), 40-45% (v/v), 35-40% (v/v), about 35% (v/v) or about 40% (v/v), wherein the combined total concentration of propylene glycol and glycerol is suitably 40-50% (v/v) e.g. 45-50% (v/v), about 45% (v/v) or about 50% (v/v); and

(iv) an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; (v) water, e.g. water for injection;

(vi) optionally an antioxidant;

(vii) optionally a non-ionic surfactant; and

(viii) optionally a preservative; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition consisting of, or consisting essentially of:

(i) vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

(ii) DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

(iii) a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 35-45% (v/v), for example 40-45% (v/v), 35-40% (v/v), about 35% (v/v) or about 40% (v/v), wherein the combined total concentration of propylene glycol and glycerol is suitably 40-50% (v/v) e.g. 45-50% (v/v), about 45% (v/v) or about 50% (v/v);

(iv) an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM;

(v) water, e.g. water for injection;

(vi) optionally an antioxidant;

(vii) optionally a non-ionic surfactant; and

(viii) optionally a preservative; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition consisting of, or consisting essentially of:

(i) vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

(ii) D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM; (iii) a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol is suitably 5-40% (v/v), 10-30% (v/v) or about 25% (v/v); and

(iv) an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM;

(v) water, e.g. water for injection;

(vi) optionally an antioxidant;

(vii) optionally a non-ionic surfactant; and

(viii) optionally a preservative; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

In one embodiment, there is provided a storage stable aqueous solution composition consisting of, or consisting essentially of:

(i) vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

(ii) DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

(iii) a mixture of propylene glycol and glycerol as cosolvent wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol is suitably 5-40% (v/v), 10-30% (v/v) or about 25% (v/v);

(iv) an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM;

(v) water, e.g. water for injection;

(vi) optionally an antioxidant;

(vii) optionally a non-ionic surfactant; and

(viii) optionally a preservative; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

As used herein when referring to the composition of the invention, the term “consists of” means that no further components are included in the composition other than those listed. As used herein when referring to the composition of the invention, the term “consists essentially of” means that specific further components can be present, but said components do not materially affect the essential characteristics of the composition, and are typically present in a de minimis amount.

Suitably the composition of the invention remains as a clear solution (e.g. as measured according to the Visual Assessment Method in the General Methods) following storage at 2-8 °C for an extended period of time, such as at least 6 months, at least 12 months, at least 18 months or at least 24 months.

Suitably the composition of the invention remains as a clear solution (e.g. as measured according to the Visual Assessment Method in the General Methods) following storage at 25 °C for at least 1 week, such as at least 2 weeks, at least 4 weeks or at least 8 weeks.

Suitably the composition of the invention comprises no more than 12% total impurities with no individual impurity being >4% (by total weight of vancomycin or pharmaceutically acceptable salt thereof in the composition) as set out in the US Pharmacopeial Monograph (Vancomycin hydrochloride for Injection, USP29), following storage at 2-8 °C for an extended period of time, such as at least 6 months, at least 12 months, at least 18 months or at least 24 months.

Suitably the composition of the invention comprises no more than 7% total impurities with no individual impurity being >4% (by total weight of vancomycin or pharmaceutically acceptable salt thereof in the composition) as set out in the European Pharmacopeial Monograph (Vancomycin hydrochloride, EP 6.0), following storage at 2-8 °C for an extended period of time, such as at least 6 months, at least 12 months, at least 18 months or at least 24 months.

Suitably the composition of the invention comprises no more than 12% total impurities with no individual impurity being >4% (by total weight of vancomycin or pharmaceutically acceptable salt thereof in the composition) as set out in the (Vancomycin hydrochloride for Injection, USP29), following storage at 25 °C for at least 1 week, such as at least 2 weeks, at least 4 weeks or at least 8 weeks. Suitably the composition of the invention comprises no more than 7% total impurities with no individual impurity being >4% (by total weight of vancomycin or pharmaceutically acceptable salt thereof in the composition) as set out in the European Pharmacopeial Monograph (Vancomycin hydrochloride, EP 6.0), following storage at 25 °C for at least 1 week, such as at least 2 weeks, at least 4 weeks or at least 8 weeks.

In one embodiment, the composition of the invention is a composition for use in therapy. In one embodiment, the composition of the invention is a pharmaceutical composition.

Vancomycin (in particular vancomycin hydrochloride) is indicated inter alia for the treatment of bacterial infection, in particular for the treatment of serious or severe bacterial infections caused by susceptible strains of methicillin-resistant (beta-lactam-resistant) staphylococci. It is indicated for penicillin-allergic patients, for patients who cannot receive or who have failed to respond to other drugs, including the penicillins or cephalosporins, and for bacterial infections caused by vancomycin-susceptible organisms that are resistant to other antimicrobial drugs. Vancomycin (in particular vancomycin hydrochloride) is indicated for initial therapy when methicillin-resistant staphylococci are suspected, but after susceptibility data are available, therapy should be adjusted accordingly.

Vancomycin (in particular vancomycin hydrochloride) is also effective in the treatment of staphylococcal endocarditis. Its effectiveness has been documented in other bacterial infections due to staphylococci, including septicaemia, bone infections, lower respiratory tract infections, skin and skin structure infections. When staphylococcal infections are localized and purulent, antibiotics are used as adjuncts to appropriate surgical measures. Vancomycin (in particular vancomycin hydrochloride) has been reported to be effective alone or in combination with an aminoglycoside for endocarditis caused by Streptococcus viridans or Streptococcus bovis. For endocarditis caused by enterococci (e.g., Enterococcus faecalis), vancomycin (in particular vancomycin hydrochloride) has been reported to be effective only in combination with an aminoglycoside. Vancomycin has been reported to be effective for the treatment of diphtheroid endocarditis. Vancomycin has been used successfully in combination with either rifampin, an aminoglycoside, or both in early-onset prosthetic valve endocarditis caused by Staphylococcus epidermidis or diphtheroids.

Accordingly, in one embodiment is provided a composition as described hereinabove for use in treating bacterial infection. In one embodiment is provided a composition as described hereinabove for use in the manufacture of a medicament for treating bacterial infection. In one embodiment is provided a method of treating bacterial infection, which comprises administering to a patient, particularly a human patient, in need thereof a therapeutically effective amount of a composition as described hereinabove. As the composition of the invention is a composition concentrate, it is typically diluted before use.

In one embodiment, the bacterial infection is caused by gram positive bacteria, and is suitably selected from the group consisting of Clostridium difficile, Listeria monocytogenes, Streptococcus pyogenes, Streptococcus pneumoniae, Streptococcus agalactiae, Streptococcus viridans, Streptococcus bovis, Staphylococcus epidermidis, multidrug resistant Staphylococcus epidermidis, Staphylococcus aureus, methicillin-resistant Staphylococcos aureus, Actinomyces species, Lactobacillus species, Enterococcus faecalis, and diphtheroids.

The vancomycin compositions of the present invention can be used as a sole therapy, or in combination with one or more other therapeutic agents. In one embodiment, the further therapeutic agent(s) is/are antibiotics, e.g. selected from the group consisting of rifampicin, an aminoglycoside (such as gentamicin), and a beta-lactam antibiotic (such as amoxicillin).

In one embodiment is provided a composition as described hereinabove for use in treating bacterial infection, with an antibiotic, e.g. selected from the group consisting of rifampicin, an aminoglycoside (such as gentamicin), and a beta-lactam antibiotic (such as amoxicillin). In one embodiment is provided an antibiotic, e.g. selected from the group consisting of rifampicin, an aminoglycoside (such as gentamicin), and a beta-lactam antibiotic (such as amoxicillin) for use in treating bacterial infection, with a composition as described hereinabove.

All embodiments described above with respect to the aqueous solution composition apply equally to methods and uses of the invention.

There is also provided a container, containing a dose or a plurality of doses of the composition as described hereinabove. The container is suitably a vial e.g. a vial made of plastics or glass. Suitably a glass vial is a type 1 glass vial e.g. containing 80% silica and 10% boric oxide, with a small amount of sodium oxide and aluminium oxide. In one embodiment is provided a multiple-dose vial, in particular a glass vial, containing the composition as described hereinabove. In one embodiment, the fill volume of the vial is 10 mL, 20 mL, 25 mL, 40 mL, 50 mL, 75 mL or 100 mL. Typically, a vial with a larger fill volume is preferred to enable use of fewest number of vials for preparation of a dose.

The composition of the invention is suitably diluted prior to administration. Once diluted, the resulting solution (ready-to-administer solution) is usually administered by intravenous

T1 infusion. A typical method for administration of a diluted composition of the invention involves transferring a volume of composition concentrate to a container which is suitably an intravenous (IV) solution bag or a bottle, where the volume of ready-to-dilute composition is calculated according to the required dose and the volume of the container. Following thorough mixing of the diluted solution, the contents of the container can be administered to the patient.

When the container is an IV solution bag, it is suitably constructed from plastic such as PVC, polyolefin, polypropylene, a blend of PO and PP (polyolefin blend), polyurethane, or a material that is substantially free of PVC, plasticizers, adhesives and latex, such as DEHP (di(2- ethylhexyl) phthalate). When the container is a bottle, it can be made from plastic (as described above for the IV solution bag) or can be made from glass, e.g. it is a type 1 glass bottle. In one embodiment, the volume of the IV solution bag or bottle is 50 ml to 1 L, e.g. 50 mL, 100 mL, 150 mL, 200 mL, 250 mL, 300 mL, 400 mL, 500 mL, 750 mL or 1 L.

The composition of the invention can be diluted in a pharmaceutically acceptable diluent such as 0.9% saline, 5% glucose in water, or water (e.g. sterile water for injection or bacteriostatic water for injection).

Suitably, the composition of the invention is diluted in a suitable diluent by mixing 1 volume part of the composition with 4-14 volume parts (e.g. 9 volume parts) of the suitable diluent to achieve the described concentration of vancomycin. The concentration of vancomycin or pharmaceutically acceptable salt thereof in the resulting ready-to-administer composition is thus 5-15 times (e.g. 10 times) lower than that in the original ready-to-dilute composition. In one embodiment, the concentration of vancomycin or pharmaceutically acceptable salt thereof in the diluted composition (ready-to-administer) is 5-15% (e.g. 10%) of the concentration in the ready-to-dilute composition. In one embodiment, the diluted composition contains 1-10 mg/mL (e.g. 2.5-7.5 mg/mL or about 5 mg/mL) vancomycin (optionally in the form of a pharmaceutically acceptable salt e.g. the hydrochloride salt).

Suitably the diluted form of the composition of the invention is free of visible particles and is a colourless to slightly yellow solution. In one embodiment, the diluted form of the composition is isotonic. In another embodiment, the diluted form of the composition is slightly hypertonic. Typically, the diluted form of the composition is slightly hypertonic. Suitably, once prepared the diluted form of the composition is stable for at least 24 hours at 2-8 °C and at least 3 hours at 25 °C and room light. Thus, in one embodiment is provided a method of preparing a solution for intravenous administration by diluting the composition concentrate as described hereinabove in a diluent selected from 0.9% saline, 5% glucose in water, and water (e.g. sterile water for injection or bacteriostatic water for injection). In one embodiment, the method provides a diluted composition comprising 1-10 mg/mL e.g. 2.5-7.5 mg/mL or about 5 mg/mL vancomycin (e.g. vancomycin hydrochloride).

The invention is further defined by the following clauses:

Clause 1 . A storage stable aqueous solution composition comprising:

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration of 25-75 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof;

- a cosolvent selected from propylene glycol and a mixture of propylene glycol and glycerol; and

- an inorganic salt containing a metal cation.

Clause 2. The storage stable aqueous solution composition according to clause 1 , wherein the vancomycin form is vancomycin hydrochloride.

Clause 3. The storage stable aqueous solution composition according to clause 1 or clause 2, wherein the concentration of vancomycin or a pharmaceutically acceptable salt thereof is 35-65 mg/mL or about 50 mg/mL.

Clause 4. The storage stable aqueous solution composition according to any one of clauses 1 to 3, wherein the composition is substantially free of, or free of L-lactic acid and salts thereof.

Clause 5. The storage stable aqueous solution composition according to any one of clauses 1 to 4, comprising sodium D-lactate, calcium D-lactate or potassium D-lactate, in particular sodium D-lactate.

Clause 6. The storage stable aqueous solution composition according to any one of clauses 1 to 3 or clause 5, wherein the source of the D-lactic acid or a pharmaceutically acceptable salt thereof is DL-lactic acid or a pharmaceutically acceptable salt thereof. Clause 7. The storage stable aqueous solution composition according to clause 6, comprising sodium DL-lactate, calcium DL-lactate or potassium DL-lactate, in particular sodium DL-lactate.

Clause 8. The storage stable aqueous solution composition according to any one of clauses 1 to 7, wherein the concentration of D-lactic acid or a pharmaceutically acceptable salt thereof is 100-1000 mM, e.g. 100-500 mM and in particular about 200 mM or about 400- 450 mM or about 400 mM.

Clause 9. The storage stable aqueous solution composition according to clause 6 or clause 7, wherein the concentration of DL-lactic acid or a pharmaceutically acceptable salt thereof is 200-1000 mM, e.g. in particular about 400-450 mM or about 400 mM or about 800 mM.

Clause 10. The storage stable aqueous solution composition according to any one of clauses 1 to 9, wherein the concentration of cosolvent selected from propylene glycol and a mixture of propylene glycol and glycerol, is 5-50% (v/v), for example 10-50% (v/v), 15-50% (v/v), 20-50% (v/v), 25-50% (v/v), 30-50% (v/v), 35-50% (v/v), 5-40% (v/v), 10-40% (v/v), 15- 40% (v/v), 20-40% (v/v), 25-40% (v/v), 30-40% (v/v), 35-40% (v/v), 5-30% (v/v), 10-30% (v/v), 15-30% (v/v), 20-30% (v/v), 25-30% (v/v), 5-25% (v/v), 10-25% (v/v), 15-25% (v/v), 20-25% (v/v), 5-20% (v/v), 10-20% (v/v), 15-20% (v/v), about 50% (v/v), about 45% (v/v), about 40% (v/v), about 35% (v/v), about 30% (v/v), about 25% (v/v), about 20% (v/v) or about 15% (v/v).

Clause H . The storage stable aqueous solution composition according to any one of clauses 1 to 10, wherein the cosolvent is propylene glycol.

Clause 12. The storage stable aqueous solution composition according to clause 11 , comprising propylene glycol at a concentration of 5-25% (v/v), for example 5-20% (v/v), 10- 20% (v/v), about 20% (v/v) or about 15% (v/v).

Clause 13. The storage stable aqueous solution composition according to any one of clauses 1 to 10, wherein the cosolvent is a mixture of propylene glycol and glycerol.

Clause 14. The storage stable aqueous solution composition according to clause 13, wherein the combined total concentration of propylene glycol and glycerol is 5-50% (v/v), for example 10-50% (v/v), 15-50% (v/v), 20-50% (v/v), 25-50% (v/v), 30-50% (v/v), 35-50% (v/v), 5-40% (v/v), 10-40% (v/v), 15-40% (v/v), 20-40% (v/v), 25-40% (v/v), 30-40% (v/v), 35-40% (v/v), 5-30% (v/v), 10-30% (v/v), 15-30% (v/v), 20-30% (v/v), 25-30% (v/v), 5-25% (v/v), 10- 25% (v/v), 15-25% (v/v), 20-25% (v/v), 5-20% (v/v), 10-20% (v/v), 15-20% (v/v), about 50% (v/v), about 45% (v/v), about 40% (v/v), about 35% (v/v), about 30% (v/v), about 25% (v/v), about 20% (v/v) or about 15% (v/v).

Clause 15. The storage stable aqueous solution composition according to clause 13 or clause 14, wherein the concentration of propylene glycol is 2-25% (v/v), for example 5-25% (v/v), 10-25% (v/v), 15-25% (v/v), 20-25% (v/v), 2-20% (v/v), 5-20% (v/v), 10-20% (v/v), 15- 20% (v/v), 2-15% (v/v), 5-15% (v/v), 10-15% (v/v), 2-10% (v/v), 5-10% (v/v), about 10% (v/v) or about 15% (v/v); and the concentration of glycerol is 35-45% (v/v), for example 40-45% (v/v), 35-40% (v/v), about 35% (v/v) or about 40% (v/v).

Clause 16. The storage stable aqueous solution composition according to clause 15, wherein the combined total concentration of propylene glycol and glycerol is 40-50% (v/v) e.g. 45-50% (v/v), about 45% (v/v) or about 50% (v/v).

Clause 17. The storage stable aqueous solution composition according to clause 15 or clause 16, wherein the ratio (v/v) of propylene glycol to glycerol is between 1 :3 and 1 :1.5.

Clause 18. The storage stable aqueous solution composition according to clause 17, wherein the concentration of propylene glycol is about 10% (v/v) and the concentration of glycerol is about 35% (v/v), or wherein the concentration of propylene glycol is about 15% (v/v) and the concentration of glycerol is about 35% (v/v).

Clause 19. The storage stable aqueous solution composition according to clause 13 or clause 14, wherein the concentration of propylene glycol is 2-25% (v/v), 5-25% (v/v), 10-25% (v/v), 15-25% (v/v), 20-35% (v/v), 2-20% (v/v), 5-20% (v/v), 10-20% (v/v), 15-20% (v/v), 2-15% (v/v), 5-15% (v/v), 10-15% (v/v), 2-10% (v/v), 5-10% (v/v), about 10% (v/v) or about 15% (v/v); and the concentration of glycerol is 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v).

Clause 20. The storage stable aqueous solution composition according to clause 19, wherein the combined total concentration of propylene glycol and glycerol is 5-40% (v/v) e.g. 10-40% (v/v), 15-40% (v/v), 20-40% (v/v), 25-40% (v/v), 30-40% (v/v), 35-40% (v/v), 5-30% (v/v), 10-30% (v/v), 15-30% (v/v), 20-30% (v/v), 25-30% (v/v), 5-25% (v/v), 10-25% (v/v), 15- 25% (v/v), 20-25% (v/v), 5-20% (v/v), 10-20% (v/v), 15-20% (v/v), about 40% (v/v), about 35% (v/v), about 30% (v/v), about 25% (v/v), about 20% (v/v) or about 15% (v/v). Clause 21. The storage stable aqueous solution composition according to clause 19 or clause 20, wherein the ratio (v/v) of propylene glycol to glycerol is between 2:1 and 1.2:1.

Clause 22. The storage stable aqueous solution composition according to clause 21 , wherein the concentration of propylene glycol is about 15% (v/v) and the concentration of glycerol is about 10% (v/v).

Clause 23. The storage stable aqueous solution composition according to any one of clauses 1 to 22, wherein the molar ratio of vancomycin or a pharmaceutically acceptable salt thereof to cosolvent is between 1 :10 and 1 :100, e.g. between 1 :20 and 1 :60.

Clause 24. The storage stable aqueous solution composition according to any one of clauses 1 to 23, wherein for the inorganic salt containing a metal cation, the metal cation is a Group 1 or Group 2 metal cation.

Clause 25. The storage stable aqueous solution composition according to clause 24, wherein the inorganic salt containing a metal cation is selected from the group consisting of sodium chloride, calcium chloride, sodium oxamate and sodium sulphate.

Clause 26. The storage stable aqueous solution composition according to clause 25, wherein the inorganic salt containing a metal cation is sodium oxamate.

Clause 27. The storage stable aqueous solution composition according to clause 25, wherein the inorganic salt containing a metal cation is sodium chloride or calcium chloride, in particular sodium chloride.

Clause 28. The storage stable aqueous solution composition according to any one of clauses 1 to 27, wherein the concentration of inorganic salt containing a metal cation is 5-300 mM, e.g. 50-200 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM.

Clause 29. The storage stable aqueous solution composition according to any one of clauses 1 to 28, wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0. Clause 30. The storage stable aqueous solution composition according to any one of clauses 1 to 29, further comprising an antioxidant selected from the group consisting of monothioglycerol, butylated hydroxyanisole, glutathione (reduced), ascorbate, cysteine and methionine, and is suitably methionine.

Clause 31. The storage stable aqueous solution composition according to clause 30, wherein the antioxidant is present at a concentration of 1-100 mM, e.g. 10-50 mM or 25-50 mM.

Clause 32. The storage stable aqueous solution composition according to any one of clauses 1 to 31 , wherein the composition is substantially free of, or free of amino acids.

Clause 33. The storage stable aqueous solution composition according to any one of clauses 1 to 32, wherein the composition is substantially free of, or free of polyethylene glycol.

Clause 34. The storage stable aqueous solution composition according to any one of clauses 1 to 33, further comprising a non-ionic surfactant.

Clause 35. The storage stable aqueous solution composition according to clause 34, wherein the non-ionic surfactant is selected from the group consisting of an alkyl glycoside, a polysorbate, an alkyl ether of polyethylene glycol, a block copolymer of polyethylene glycol and polypropylene glycol, and an alkylphenyl ether of polyethylene glycol.

Clause 36. The storage stable aqueous solution composition according to clause 35, wherein the non-ionic surfactant is an alkyl glycoside which is suitably selected from the group consisting of dodecyl maltoside, dodecyl glucoside, octyl glucoside, octyl maltoside, decyl glucoside, decyl maltoside, decyl glucopyranoside, tridecyl glucoside, tridecyl maltoside, tetradecyl glucoside, tetradecyl maltoside, hexadecyl glucoside, hexadecyl maltoside, sucrose monooctanoate, sucrose monodecanoate, sucrose monododecanoate, sucrose monotridecanoate, sucrose monotetradecanoate and sucrose monohexadecanoate; and in particular is dodecyl maltoside or decyl glucopyranoside, especially dodecyl maltoside.

Clause 37. The storage stable aqueous solution composition according to clause 35, wherein the non-ionic surfactant is a polysorbate which is suitably polysorbate 20 or polysorbate 80. Clause 38. The storage stable aqueous solution composition according to clause 35, wherein the non-ionic surfactant is an alkyl ether of polyethylene glycol which is suitably selected from the group consisting of polyethylene glycol (2) hexadecyl ether (Brij 52), polyethylene glycol (2) oleyl ether (Brij 93), polyethylene glycol (2) dodecyl ether (Brij L4), polyethylene glycol (4) lauryl ether (Brij 30), polyethylene glycol (10) lauryl ether (Brij 35), polyethylene glycol (20) hexadecyl ether (Brij 58) and polyethylene glycol (10) stearyl ether (Brij 78).

Clause 39. The storage stable aqueous solution composition according to clause 35, wherein the non-ionic surfactant is a block copolymer of polyethylene glycol and polypropylene glycol, which is suitably selected from the group consisting of poloxamer 188, poloxamer 407, poloxamer 171 or poloxamer 185.

Clause 40. The storage stable aqueous solution composition according to clause 35, wherein the non-ionic surfactant is alkylphenyl ether of polyethylene glycol, which is suitably 4-(1 , 1 ,3,3-tetramethylbutyl)phenyl-polyethylene glycol.

Clause 41. The storage stable aqueous solution composition according to any one of clauses 34 to 40, wherein the non-ionic surfactant is present at a concentration of 1-5000 pg/mL, 1-1000 pg/mL, such as 5-500 pg/mL, 10-400 pg/mL, 20-400 pg/mL, 50-400 pg/mL, 10-300 pg/mL, 20-300 pg/mL, 50-300 pg/mL, 10-200 pg/mL, 20-200 pg/mL, 50-200 pg/mL, 10-100 pg/mL, 20-100 pg/mL, 50-100 pg/mL or around 50 pg/mL.

Clause 42. The storage stable aqueous solution composition according to any one of clauses 1 to 41 , further comprising a preservative such as a phenolic or benzylic preservative.

Clause 43. The storage stable aqueous solution composition according to clause 42, wherein the phenolic or benzylic preservative is selected from the group consisting of phenol, m-cresol, chlorocresol, benzyl alcohol, propyl paraben and methyl paraben.

Clause 44. The storage stable aqueous solution composition according to any one of clauses 1 to 43, comprising at least 95% (v/v) of water, such as at least 90% (v/v), at least 85% (v/v), at least 80% (v/v), at least 75% (v/v), at least 70% (v/v), at least 65% (v/v), at least 60% (v/v), at least 55% (v/v) or at least 50% (v/v) of water, e.g. sterile water for injection or bacteriostatic water for injection. Clause 45. The storage stable aqueous solution composition according to any one of clauses 1 to 44, wherein the osmolarity of the composition is 1500-8000 mOsm/L, such as 2000-6000 mOsm/L, such as 3000-6000 mOsm/L.

Clause 46. The storage stable aqueous solution composition according to clause 1 , comprising

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM, or DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

- propylene glycol as cosolvent, at a concentration of 5-25% (v/v), for example 5-20% (v/v), 10-20% (v/v), about 20% (v/v) or about 15% (v/v); and

- an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

Clause 47. The storage stable aqueous solution composition according to clause 1 , comprising

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM, or DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

- a mixture of propylene glycol and glycerol as cosolvent, wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 35-45% (v/v), for example 40-45% (v/v), 35-40% (v/v), about 35% (v/v) or about 40% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 40- 50% (v/v) e.g. 45-50% (v/v), about 45% (v/v) or about 50% (v/v); and - an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

Clause 48. The storage stable aqueous solution composition according to clause 1 , comprising

- vancomycin or a pharmaceutically acceptable salt thereof, at a concentration 25-75 mg/mL, e.g. 35-65 mg/mL or about 50 mg/mL;

- D-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 100-1000 mM, e.g. 200-1000 mM, 100-500 mM, 200-500 mM, about 400-450 mM or about 400 mM or about 200 mM, or DL-lactic acid or a pharmaceutically acceptable salt thereof, at a concentration of 200-1000 mM, e.g. 400-1000 mM, 500-1000 mM, about 800 mM or about 400-450 mM or about 400 mM;

- a mixture of propylene glycol and glycerol as cosolvent, wherein the propylene glycol is present at a concentration of 5-25% (v/v), for example 5-20% (v/v), 5-15% (v/v), 10-20% (v/v), about 10% (v/v) or about 15% (v/v) and the glycerol is present at a concentration of 2-10% (v/v), e.g. 5-10% (v/v), about 5% (v/v) or about 10% (v/v), wherein the combined total concentration of propylene glycol and glycerol as cosolvent is suitably 5-40% (v/v), 10-30% (v/v) or about 25% (v/v); and

- an inorganic salt containing a Group 1 or Group 2 metal cation, in particular sodium oxamate, sodium chloride or calcium chloride, at a concentration of 5-300 mM, e.g. 50-200 mM, 50-150 mM, 50-100 mM, 100-200 mM, about 75 mM, about 100 mM, about 150 mM, or about 200 mM; wherein the pH of the composition is in the range 4.0 to 6.0, such as about 5.0.

Clause 49. The storage stable aqueous solution composition according to any one of clauses 1 to 48, which is a pharmaceutical composition.

Clause 50. The storage stable aqueous solution composition according to any one of clauses 1 to 48, or the pharmaceutical composition according to clause 49, for use in therapy.

Clause 51. The storage stable aqueous solution composition or pharmaceutical composition according to clause 50, for use in treating bacterial infection. Clause 52. A method of treating bacterial infection which comprises administering to a patient in need thereof a therapeutically effective amount of a storage stable aqueous solution composition according to any one of clauses 1 to 48, or a pharmaceutical composition according to clause 49.

Clause 53. The storage stable aqueous solution composition for use according to clause 51 , or the method according to clause 52, wherein the bacterial infection is caused by gram positive bacteria, and is suitably selected from the group consisting of Clostridium difficile, Listeria monocytogenes, Streptococcus pyogenes, Streptococcus pneumoniae, Streptococcus agalactiae, Streptococcus viridans, Streptococcus bovis, Staphylococcus epidermidis, multidrug resistant Staphylococcus epidermidis, Staphylococcus aureus, methicillin-resistant Staphylococcos aureus, Actinomyces species, Lactobacillus species, Enterococcus faecalis, and diphtheroids.

Clause 54. The storage stable aqueous solution composition for use or the method according to any one of clauses 50 to 53, for use in combination with one or more further therapeutic agent(s).

Clause 55. The storage stable aqueous solution composition for use or the method according to clause 54, wherein the one or more further therapeutic agent(s) is/are selected from the group consisting of rifampicin, an aminoglycoside (such as gentamicin), and a betalactam antibiotic (such as amoxicillin).

Clause 56. The storage stable aqueous solution composition for use or the method according to any one of clauses 50 to 55, wherein the composition in ready-to-dilute form, and is diluted prior to administration.

Clause 57. The storage stable aqueous solution composition for use or the method according to clause 56, wherein the ready-to-dilute composition is diluted with a diluent e.g. selected from 0.9% saline, 5% glucose in water, and water (e.g. sterile water for injection or bacteriostatic water for injection).

Clause 58. The storage stable aqueous solution composition for use or the method according to clause 56 or clause 57, wherein the concentration of vancomycin or pharmaceutically acceptable salt thereof in the diluted composition (ready-to-administer form) is 5-15%, such as 10% of the concentration in the ready-to-dilute form. 1 Clause 59. The storage stable aqueous solution composition for use or the method according to any one of clauses 56 to 58, wherein the concentration of vancomycin or a pharmaceutically acceptable salt thereof in the diluted composition (ready-to-administer form) is 1-10 mg/mL, e.g. 2.5-7.5 mg/mL or about 5 mg/mL.

Clause 60. The storage stable aqueous solution composition for use or the method according to any one of clauses 56 to 59, wherein following dilution of the ready-to-dilute composition, the diluted composition (ready-to-administer form) is administered via intravenous infusion.

Clause 61. A method of preparing a solution for intravenous administration (ready-to- administer form) by diluting a ready-to-dilute composition according to any one of clauses 1 to 49, with a diluent e.g. selected from 0.9% saline, 5% glucose in water, and water (e.g. sterile water for injection or bacteriostatic water for injection).

Clause 62. The method according to clause 61 , wherein the concentration of vancomycin or pharmaceutically acceptable salt thereof in the diluted composition (ready-to-administer) is 5-15%, such as 10% of the concentration in the ready-to-dilute composition.

Clause 63. The method according to clause 61 or clause 62, wherein the concentration of vancomycin or a pharmaceutically acceptable salt thereof in the diluted composition (ready- to-administer form) is 1-10 mg/mL, e.g. 2.5-7.5 mg/mL or about 5 mg/mL.

Clause 64. A ready-to-administer composition for intravenous administration of vancomycin or a pharmaceutically acceptable salt thereof, prepared according to the method of any one of clauses 61 to 63.

Clause 65. A vial which is suitably a glass vial containing the storage stable aqueous solution composition according to any one of clauses 1 to 49.

Clause 66. The vial according to clause 65, which is a multiple dose vial.

Examples

General Methods

Reversed-Phase Chromatography Method (RP-HPLC) High performance reverse phase chromatography is performed using the Thermo-Scientific Ultimate 3000 HPLC with Diode Array Detector (DAD3000) with a Zorbax Stable Bond C18 250 mm by 4.6 mm, 5 pm particle size and 80 A pore size. Mobile Phase A is a mixture of triethylamine buffer (mix 4 mL of triethylamine and 2000 mL of water, and adjust with phosphoric acid to a pH of 3.2), acetonitrile and tetrahydrofuran in volume per volume ratio of 92:7:1. Mobile Phase B is a mixture of triethylamine buffer, acetonitrile, and tetra hydrofuran in volume per volume ratio of 70:29:1. The sample comprising vancomycin (or pharmaceutically acceptable salt thereof) is bound in Mobile Phase A and eluted using a gradient of Mobile Phase A and Mobile Phase B. The sample volume is 20 microlitres, the flow rate is 1 .0 mL/min, with 284 nm UV detection. All analyses are performed at 25 °C.

Visual Assessment Method

Visible particles are suitably detected using the 2.9.20. European Pharmacopoeia Monograph (Particulate Contamination: Visible Particles). The apparatus required consists of a viewing station comprising:

• a matt black panel of appropriate size held in a vertical position

• a non-glare white panel of appropriate size held in a vertical position next to the black panel

• an adjustable lampholder fitted with a suitable, shaded, white-light source and with a suitable light diffuser (a viewing illuminator containing two 13 W fluorescent tubes, each 525 mm in length, is suitable). The intensity of illumination at the viewing point is maintained between 2000 lux and 3750 lux.

Any adherent labels are removed from the container and the outside washed and dried. The container is gently swirled or inverted, ensuring that air bubbles are not introduced, and observed for about 5 s in front of the white panel. The procedure is repeated in front of the black panel. The presence of any particles is recorded. The visual scores are ranked as follows:

Visual score 1 : Clear solution, virtually free of particles

Visual score 2: ~ 5 very small particles

Visual score 3: -10-20 very small particles

Visual score 4: 20-50 particles, including larger particles

Visual score 5: >50 particles, including larger particles

Whilst the particles in samples with visual scores 4 and 5 are clearly detectable on casual visual assessment under normal light, samples with visual score 1-3 generally appear as clear solutions on the same assessment. Samples with visual scores 1-3 are considered to be “Pass”; samples with visual score 4-5 are considered to be “Fail”. Example 1 : Composition Examples

The following example aqueous compositions may be prepared.

Example A:

Vancomycin hydrochloride 50 mg/mL

D-lactic acid 200 mM

Propylene glycol 20% (v/v)

Sodium chloride 100 mM pH 5.0

Example B:

Vancomycin hydrochloride 50 mg/mL

D-lactic acid 400 mM

Propylene glycol 20% (v/v)

Sodium chloride 100 mM pH 5.0

Example C:

Vancomycin hydrochloride 50 mg/mL

Sodium D-lactate 200 mM

Propylene glycol 20% (v/v)

Sodium chloride 100 mM pH 5.0

Example D:

Vancomycin hydrochloride 50 mg/mL

Sodium D-lactate 400 mM

Propylene glycol 20% (v/v)

Sodium chloride 100 mM pH 5.0

Example E:

Vancomycin hydrochloride 50 mg/mL

D-lactic acid 200 mM Propylene glycol 15% (v/v)

Glycerol 10% (v/v)

Sodium chloride 100 mM pH 5.0

Example F:

Vancomycin hydrochloride 50 mg/mL

D-lactic acid 400 mM

Propylene glycol 15% (v/v)

Glycerol 10% (v/v)

Sodium chloride 100 mM pH 5.0

Example G:

Vancomycin hydrochloride 50 mg/mL

D-lactic acid 200 mM

Propylene glycol 15% (v/v)

Glycerol 10% (v/v)

Sodium oxamate 100 mM pH 5.0

Example H:

Vancomycin hydrochloride 50 mg/mL

D-lactic acid 400 mM

Propylene glycol 15% (v/v)

Glycerol 10% (v/v)

Sodium oxamate 100 mM pH 5.0

Example I:

Vancomycin hydrochloride 50 mg/mL

D-lactic acid 200 mM

Propylene glycol 15% (v/v) Glycerol 10% (v/v)

Sodium chloride 200 mM pH 5.0

Example J:

Vancomycin hydrochloride 50 mg/mL

D-lactic acid 400 mM

Propylene glycol 15% (v/v)

Glycerol 10% (v/v)

Sodium chloride 200 mM pH 5.0

Example K:

Vancomycin hydrochloride 50 mg/mL

D-lactic acid 200 mM

Propylene glycol 15% (v/v)

Glycerol 35% (v/v)

Sodium chloride 100 mM pH 5.0

Example L:

Vancomycin hydrochloride 50 mg/mL

D-lactic acid 400 mM

Propylene glycol 15% (v/v)

Glycerol 35% (v/v)

Sodium chloride 100 mM pH 5.0

Example M:

Vancomycin hydrochloride 50 mg/mL

D/L-lactic acid 400 mM

Propylene glycol 15% (v/v)

Glycerol 10% (v/v) Sodium chloride 100 mM pH 5.0

Example N:

Vancomycin hydrochloride 50 mg/mL

D/L-lactic acid 800 mM

Propylene glycol 15% (v/v)

Glycerol 10% (v/v)

Sodium chloride 100 mM pH 5.0

Example O:

Vancomycin hydrochloride 50 mg/mL

Sodium D-lactate 800 mM

Propylene glycol 15% (v/v)

Glycerol 10% (v/v)

Sodium chloride 100 mM pH 5.0

In all of the above compositions the pH of the composition is adjusted to the required pH by the addition of a base such as sodium hydroxide. It should be noted that in cases where “sodium chloride” is listed as a composition component, the stated amount of sodium chloride is added to the composition.

Example 2: Effect of pH on stability of vancomycin compositions

The effect of pH on the stability of vancomycin compositions following storage for 3 days at 60 °C was investigated using the RP-HPLC described in General Methods. All compositions contained 5 mg/mL vancomycin hydrochloride in water for injection (WFI). The results are shown in Table 1 which shows % impurities observed in the compositions at time zero (TO) and after storage for 3 days at 60 °C.

Table 1 : Stability of vancomycin hydrochloride (5 mg/mL) compositions assessed using RP- HPLC

It can be seen from Table 1 that the pH range 4.5-6.5 was the most stable, with the degradation rate accelerating either side of these ranges and being much quicker at more alkaline pH. All compositions in subsequent examples were prepared at pH 5.0.

Example 3: Effect of composition excipients on stability of vancomycin

The effect of individual composition excipients N-acetyl-D-alanine (NADA), PEG400 and lysine hydrochloride on the stability of vancomycin was investigated using the RP-HPLC method described in General Methods. All compositions comprised 5 mg/mL vancomycin hydrochloride in water for injection (WFI) and the additional excipients as set out in Table 2 below, and were adjusted to pH 5.0. Table 2 shows % impurities observed in the compositions at time zero (TO) and after storage for 15 and 30 days at 25 °C. Composition 7 corresponds to the marketed composition of VancoReady™.

Table 2: Stability of vancomycin hydrochloride (5 mg/mL) compositions expressed as % impurities vs. time zero (TO)

*(VancoReady™ composition)

It can be seen from Table 2 that removal of NADA from the VancoReady™ product resulted in a significant impairment in stability (comparing compositions 7 and 8). Removal of PEG400 or lysine HCI appeared to have no significant impact on the stability of the vancomycin compositions. As such, NADA appears to be the key stabilizing excipient in VancoReady™. Example 4: Stability of vancomycin compositions in the presence of various organic acids and propylene glycol

The effect of various excipients (N-acetyl-D-alanine (NADA), N-acetyl-L-alanine (NALA), PEG400, lysine hydrochloride, sodium D-lactate, sodium L-lactate and propylene glycol (PG)) on the stability of vancomycin compositions was investigated using the RP-HPLC method described in General Methods. All compositions comprised 5 mg/mL vancomycin hydrochloride in water for injection (WFI) and the additional excipients as set out in Table 3 below, and were adjusted to pH 5.0. Table 4 shows % impurities observed in the compositions at time zero (TO) and after storage for 6, 12, 40, and 69 days at 25 °C. Composition 7 corresponds to the marketed composition of VancoReady™.

Table 3: Vancomycin hydrochloride (5 mg/mL) compositions

*(VancoReady™ composition)

Table 4: Stability of vancomycin hydrochloride (5 mg/mL) compositions assessed using RP-

HPLC

*(VancoReady™ composition)

**(Analysis not performed due to sample failing visual inspection due to precipitation of the formulation) Comparing compositions 7 and 8, again it can be seen that removal of NADA from the VancoReady™ composition results in a significant impairment in stability. Replacing NADA with N-acetyl-L-alanine (NALA) also resulted in a significant impairment in stability (comparing compositions 7 and 13). However, when NADA was replaced with sodium D-lactate, the reduction in composition stability was considerably smaller (comparing compositions 7 and 14). The same effect was not observed for sodium L-lactate, where stability was considerably reduced (comparing compositions 7 and 16). Modifying the compositions containing sodium D-lactate and sodium L-lactate to replace the PEG400 with propylene glycol, a surprising relative increase in stability was observed (comparing compositions 14 and 15, and compositions 16 and 17).

Example 5: Stability of vancomycin compositions in the presence of higher concentrations of D-lactate and propylene glycol, and in the presence of inorganic salts

The effect of varying concentrations of sodium D-lactate and propylene glycol (PG), and the effect of adding inorganic salts to vancomycin compositions was investigated using the RP- HPLC method described in General Methods. All compositions comprised 5 mg/mL vancomycin hydrochloride in water for injection (WFI) and the additional amounts excipients as set out in Table 5 (below) and were adjusted to pH 5.0. Table 6 shows the increase in % total impurities (compared with time zero) following storage for 2, 4, and 8 weeks at 25 °C.

Table 5: Vancomycin hydrochloride (5 mg/mL) compositions

Table 6: Stability of vancomycin hydrochloride (5 mg/mL) compositions assessed using RP- HPLC It can be seen from Table 6 that increasing the concentration of sodium D-lactate leads to an improvement in composition stability (comparing compositions 18 and 19), as does increasing the concentration of propylene glycol (comparing compositions 20 and 21). The addition of inorganic salt sodium chloride provides a further stabilizing effect (comparing compositions 18 and 21).

Example 6: Stability of vancomycin compositions (5 mg/mL) in the presence of varying concentrations of D-lactate, DL-lactate and propylene glycol, and further excipients

The effect of varying concentrations of sodium D-lactate, sodium DL-lactate and propylene glycol (PG) on the stability of vancomycin compositions was investigated using the RP-HPLC method described in General Methods. The effect of adding sodium oxamate, polysorbate 80 and methionine was also investigated. All compositions comprised 5 mg/mL vancomycin hydrochloride in water for injection (WFI) and the additional amounts excipients as set out in Table 7 below, and were adjusted to pH 5.0. Table 8 shows the increase in % total impurities (compared with time zero) following storage for 8 weeks at 2-8 °C, and for 8 weeks at 25 °C.

Table 7: Vancomycin hydrochloride (5 mg/mL) compositions

Table 8: Stability of vancomycin hydrochloride (5 mg/mL) compositions assessed using RP- HPLC

It can be seen from Table 8 that increasing the concentration of sodium D-lactate results in improved composition stability (comparing compositions 23 and 26, 24 and 27, and 25 and 28). Increasing the concentration of PG also results in improved composition stability (comparing compositions 23-24, and compositions 26-28). Interestingly, the racemic form of lactate (sodium DL-lactate) also provides a stabilizing effect, but the concentration must be twice as high as if D-lactate is used for a comparable stabilizing effect (comparing compositions 28-30).

The addition of sodium oxamate leads to an improvement in stability (comparing compositions 24 and 31). The addition of methionine results in a small improvement of stability (comparing compositions 25 and 32), as does the addition of polysorbate 80 (comparing compositions 24 and 33, and 25 and 34).

Example 7: Stability of vancomycin compositions (50 mg/mL) in the presence of varying concentrations of D-lactate, DL-lactate and propylene glycol, and sodium chloride

The effect of varying concentrations of sodium D-lactate, sodium DL-lactate and propylene glycol (PG) on the stability of vancomycin compositions was investigated using the RP-HPLC method described in General Methods. The effect of adding sodium chloride and glycerol was also investigated. All compositions comprised 50 mg/mL vancomycin hydrochloride in water for injection (WFI) and the additional amounts excipients as set out in Table 9 below, and were adjusted to pH 5.0. Table 10 shows the increase in % total impurities (compared with time zero) following storage for 8 weeks at 2-8 °C, and for 8 weeks at 25 °C.

Table 9: Vancomycin hydrochloride (50 mg/mL) compositions

Table 10: Stability of vancomycin hydrochloride (50 mg/mL) compositions assessed using RP- HPLC

* Analysis not performed due to sample failing visual inspection due to precipitation and formation of a gel

It can be seen from Table 10 that increasing the concentration of sodium D-lactate results in improved composition stability (comparing compositions 23 and 26). Increasing the concentration of PG also results in improved composition stability (comparing compositions 23 and 24). Interestingly, the racemic form of lactate (sodium DL-lactate) also provides a stabilizing effect, but the concentration must be twice as high as if D-lactate is used for a comparable stabilizing effect (comparing compositions 24 and 28).

The addition of sodium chloride leads to an improvement in stability (comparing compositions 23 and 29). The use of glycerol instead of propylene glycol results in a decrease in stability (comparing compositions 26 and 27), but a combination of propylene glycol and glycerol provides a similar stabilizing effect to the use of propylene glycol alone (comparing compositions 24 and 25).

Example 8: Stability of vancomycin compositions (50 mg/mL) in the presence of inorganic salts containing a metal cation The effect of adding sodium chloride and calcium chloride on the stability of vancomycin compositions was investigated using the Visual Assessment Method described in General Methods. All compositions comprised 50 mg/mL vancomycin hydrochloride in water for injection (WFI), sodium D-lactate and propylene glycol and glycerol in the amounts shown in Table 11 (below), and were adjusted to pH 5.0. Table 12 shows the visual appearance of the compositions following storage for 19 weeks at 25 °C.

Table 11 : Vancomycin hydrochloride (50 mg/mL) compositions

Table 12: Stability of vancomycin hydrochloride (50 mg/mL) compositions assessed using visual assessment

It can be seen from Table 12 the addition of both sodium chloride and calcium chloride provided a significant improvement in stability of the compositions when stored at 2-8 °C.

Example 9: Long-term stability of ready-to-dilute vancomycin compositions (50 mg/mL)

Long-term stability trials for two compositions were set up at 2-8 °C and 25 °C. Both compositions comprised 50 mg/mL vancomycin hydrochloride and additional excipients shown in Table 13 and were adjusted to pH 5.0. Compositions were filled, under aseptic conditions, into type 1 glass vials. The stability of the compositions at 2-8 °C and 25 °C was investigated using the RP-HPLC and Visual Assessment methods described in General Methods. All compositions remained clear and colourless (Visual score 1) throughout the long- term stability trials. The RP-HPLC results, in particular the increase in % total, and specific individual, impurities are shown in Tables 14-15 (2-8 °C) and 16-17 (25 °C).

Table 13: Vancomycin hydrochloride (50 mg/mL) compositions

Table 14: Stability of Composition No. 35 following storage at 2-8 °C, assessed using RP- HPLC

Table 15: Stability of Composition No. 36 following storage at 2-8 °C, assessed using RP- HPLC

Table 16: Stability of Composition No. 35 following storage at 25 °C, assessed using RP- HPLC Table 17: Stability of Composition No. 36 following storage at 25 °C, assessed using RP- HPLC

Significantly, the US Pharmacopeial Monograph (Vancomycin hydrochloride for Injection, USP29) requires that a vancomycin drug product has the following purity:

• No less than 88% vancomycin purity (i.e. no more than 12% total impurities)

• No more than 4% of any individual impurity

The results in Table 14-17 demonstrate that the trialled compositions (Compositions No. 35 and 36) are long-term storage stable, and in particular are in compliance with the conditions set out in the US Pharmacopeial Monograph (USP29), upon storage at both 2-8 °C and 25 °C for 6 months.

These results indicate that the trialled compositions (Compositions No. 35 and 36) are expected to have a shelf-life of at least 24 months at 2-8 °C, and that said compositions are expected to remain stable, and furthermore remain compliant with the conditions set out in the US Pharmacopeial Monograph (USP29), following an excursion at 25 °C for 6 months prior to use.