SOLUBLE COMPLEXES OF CURCUMIN

Background of the Invention

Field of the Invention

The present invention relates to water-soluble curcumin complexes. In particular, the invention concerns aqueous compositions containing water-soluble and stable curcumin complexes. The invention also concerns methods of solubilizing curcumin by forming stable cyclodextrin complexes. Further, the present invention relates to pharmaceutical and nutraceutical formulations of curcumin and a composition and methods of protecting cells and organs.

Description of Related Art

Curcumin, chemically called diferuloylmethane, is a hydrophobic polyphenol derived from the rhizome of the perennial herb Curcuma longa. It has a wide spectrum of biological and pharmacological activities. Curcumin isolated from turmeric powder contains two other curcuminoids, demethoxycurcumin and bisdemethoxycurcumin, which differ in their biological activities. Curcumin is the most active curcuminoid in most in vitro bioassays (1) but even the other curcuminoids have proven effective in some disease models.

Curcumin has been shown to exhibit potent anti-inflammatory, immunomodulatory, antiproliferative and anticarcinogenic activities and protect cells and tissues against various injury mechanisms. A number of preclinical studies have indicated that curcumin is a promising therapeutic agent for several diseases and clinical conditions, including, for example, the treatment of cancer and leukemias, stroke, myocardial infarction, rheumatoid arthritis, inflammatory bowel disease, pancreatitis, sepsis, hemorrhagic shock, organ transplantations, and radiation injury.

Several molecular targets have been identified for curcumin, and the interactions of curcumin with these targets explain at least part of the therapeutic effects identified in animal disease models. Furthermore, curcumin has proved to be remarkably safe in animal studies and phase I clinical trials even at high dose levels.

A problem limiting the exploitation of curcumin's potentially valuable therapeutic effects is its low bioavailability. In practice, only very low levels of curcumin can be achieved in blood and tissues by oral administration of curcumin (2). The low bioavailability of curcumin has so far limited its clinical use to prevention, and possible treatment, of diseases of the gastrointestinal tract.

Major reasons contributing to the low bioavailability of curcumin are its very low aqueous solubility and rapid intestinal metabolism, particularly in human subjects. Furthermore, the poor aqueous solubility has hindered the development of pharmaceutical formulations suitable for intravenous administration, which would lead to effective concentrations of curcumin in tissues.

To mitigate the low adsorption of oral curcumin, US Published Patent Application No. 20060067998 describes colloidal drug delivery systems for parenteral administration of curcumin. The inventors disclose a liposomal drug delivery system and polymer-based nanoparticles and microparticles. Generally, water- insoluble drugs like curcumin incorporate into lipid membranes in liposomes and not to the aqueous phase inside the liposomes, which may limit the amount of the incorporated drug and its stability.

Curcumin is generally known to hydro lyze rapidly at neutral and alkaline pH (3). The stability of curcumin in the liposomal and other colloidal drug delivery systems has not been described. In a preclinical study with liposomal curcumin, freeze-dried liposomes were stored frozen, suggesting limited stability. On the other hand, the dosing was reported to be limited by the administered volume, suggesting that the concentration of liposomal curcumin was not high enough (4).

A few scientific publications have addressed interactions of curcumin with cyclodextrins (5, 6, 7). Cyclodextrins are cyclic oligosaccharides consisting of α(l-4)-linked glucopyranose units, which form a lipophilic cavity and a hydrophilic outer surface. Their apolar cavity is able to include hydrophobic molecules by non-covalent forces and thereby improve their water solubility. However, the reported experiments suggest that only relatively low concentrations of curcumin can be solubilized even with a high molar excess of cyclodextrins, and the described complexes are not suitable for therapeutic use. DE

Patent Application No. 10233598 describes cosmetic or dermatological compositions containing curcumin and cyclodextrins. However, it is not demonstrated that the described compositions would contain curcumin in water-soluble form and the examples of the application describe only oil in water emulsions, which are not suitable for e.g. parenteral administration.

The present invention seeks to alleviate the problems associated with curcumin administration by seeking novel methods to solubilize curcumin in concentrations high enough to allow administration in effective doses to human and animal subjects. Further, the present invention seeks to provide stable water-soluble formulations of curcumin which make possible the manufacture of pharmaceutical and nutraceutical formulations of curcumin. Finally, the present invention also seeks to provide compositions and methods for the protection of organs and cells.

Summary of the Invention

It is an aim of the invention to provide novel water-soluble and stable compositions of curcumin.

It is a second aim of the invention to provide a method of manufacturing novel cyclodextrin complexes of curcumin.

It is a third aim of the invention to provide a method of manufacturing water-soluble and stable composition of curcumin.

It is a fourth aim of the invention to provide novel pharmaceutical compositions of curcumin, which can be administered to human and animal subjects at effective doses for the treatment of various diseases and clinical conditions.

It is a fifth aim of the present invention to provide novel compositions and methods for protection of cells, tissues and organs during hypothermic preservation, perfusion, and reperfusion.

It is still a sixth aim of the present invention to provide novel, endotoxin- free compositions of curcumin.

The present invention is based on the unexpected finding that it is possible to dissolve curcumin at high concentrations in an alkaline aqueous solution containing a chemically modified derivative of γ-cyclodextrin. By lowering the pH of the aqueous solution below 8 a cyclodextrin complex of curcumin is obtained which is stable in the aqueous solution.

The cyclodextrin complex obtainable by the present invention is soluble at much higher curcumin concentrations in aqueous solutions than previously described cyclodextrin complexes or other curcumin formulations, and the molar excess of cyclodextrin required for solubilization of curcumin is clearly lower than previously described. Curcumin is also remarkably stable in the described complex and has much better stability than in the previously described complexes.

The cyclodextrin complex of curcumin can be formulated to pharmaceutical compositions suitable for administration parenterally, orally or topically to human or animal subjects. Importantly, the new curcumin formulations enable intravascular administration of curcumin at effective doses for treatment of serious diseases and clinical conditions.

The solution composition of curcumin can be also added to preservation and perfusion solutions of organs, tissues and cells ex vivo. Further, the complex can be used for the manufacture of nutraceutical preparations containing curcumin.

The method according to the present invention of manufacturing an endotoxin- free formulation of curcumin comprises dissolving curcumin at a pH of at least 11 to form a solution, lowering the pH of the solution to below pH 8 in the presence of a complexing agent, such as cyclodextrin or albumin, and recovering the solution thus obtained. By the present uncomplicated method, endotoxins can be efficiently removed from the biological raw materials used.

Brief Description of the Drawings

Figure 1 shows the effect of pH during contacting of curcumin with cyclodextrin during manufacturing of the complex. 2-Hydroxypropyl-γ-cyclodextrin was dissolved at 150 g/1 in 1 - 200 mmol/1 sodium hydroxide solutions, and curcumin was added to a concentration of 11.7 g/1. The solutions were agitated for 10 min, pH was measured and adjusted to 7.0 with 0.5 M hydrochloric acid. Curcumin concentration was determined by HPLC and absorbance at 430 nm.

Figure 2 shows the effect of pH after adjustment of the solution containing the cyclodextrin complex of curcumin on stability of curcumin. The 2-hydroxypropyl-γ-cyclodextrin complex of curcumin was manufactured at pH 12.3 as described in Example 3 and the solution was adjusted to different pH values between pH 5.0 and pH 11.3 with 0.5 M citric acid. The solutions were stored for 7 days at 23 ⁰ C protected from light, after which the concentration of curcumin was determined by HPLC.

Detailed Description of Preferred Embodiments

Suitable cyclodextrins for the manufacture of a cyclodextrin complex of the present invention are ether derivatives of γ-cyclodextrin. In particular the derivatives are

(substituted)alkyl ether derivatives of γ-cyclodextrin, wherein the alkyl group is branched or linear and comprises 1 to 6 carbon atoms. Preferably the alkyl group is substituted with 1 to 3 substituents selected from the group consisting of hydroxy, sulfoxy, amino and thio groups. As examples of suitable ethers, hydroxyalkyl and sulfoalkyl ether derivatives can be particularly mentioned.

According to one embodiment, the hydroxyalkyl group is hydroxypropyl, dihydroxypropyl or hydroxyethyl and the sulfoalkyl group is sulfobutyl.

The degree of substitution (DS) of the cyclodextrin ether is typically 3 - 10. The degree of substitution as used here means the average number of etherifying groups, such as hydroxyalkyl or sulfoalkyl groups, per cyclodextrin molecule.

The γ-cyclodextrin may also contain alkyl substituents, such as methyl or ethyl groups. Glucosyl and maltosyl derivatives of γ-cyclodextrin may be also used.

According to a specific embodiment the cyclodextrin is a 2-hydroxypropyl-γ-cyclodextrin with a substitution degree of 3 to 7. 2-Hydroxypropyl-γ-cyclodextrin suitable for the manufacturing of the curcumin complex is supplied by Wacker Chemie AG, Munich, Germany, under the tradename "CAVASOL W8 Pharma".

The cyclodextrin complex can contain other curcuminoids than curcumin. A curcuminoid composition similar to the naturally occurring composition in turmeric powder is suitable. Commercially available curcumin preparations obtained by extraction of turmeric powder contain 95 % or more curcuminoids of which about 70 - 80 % is curcumin, 15 - 25 % desmethoxycurcumin and 3 - 7 % bisdesmethoxycurcumin. Any of the curcuminoids can be used in pure form. Synthetic curcuminoids can be also used. As used hereafter, by "curcumin" it is meant curcumin, desmethoxycurcumin and bisdesmethoxycurcumin, and mixtures thereof.

Methods for the isolation of curcumin from turmeric powder have been described for example in US Patent No. 5,861,415 and in (1). Curcumin and other curcuminoids may be further purified, for example by chromatography using silica gel 60 as described in (1).

With "water-soluble" it is meant that the cyclodextrin complex of curcumin is soluble at a concentration of at least 10 mmol/1 in aqueous solutions without precipitation. The complex is typically also "stable" which means that the concentration of curcumin in the complex decreases less than 20 % during storage for three months at room temperature (23 ± 2 ⁰ C) or alternatively during storage for twelve months at 2 to 8 ⁰ C, when protected from light.

The complex is manufactured by contacting curcumin with the cyclodextrin in an alkaline aqueous solution at a pH of at least pH 11, preferentially at least pH 12. A suitable alkaline solution is for example 0.1 - 0.5 mo 1/1 sodium hydroxide.

A cyclodextrin concentration of 10 - 250 g/1 is suitable, but higher concentrations may be used. Curcumin is added at a molar ratio from 1:1 to 1 :6 to cyclodextrin, and the solution is

agitated. The solution is protected from light during manufacturing to prevent curcumin degradation. The pH is adjusted to below 8, but not less than about 3, in particular to about 4.0 - 7.6.

The pH can be adjusted, for example, with hydrochloric, phosphoric acid or organic acids, such as citric acid, lactic acid, malic acid, tartaric acid, acetic acid, gluconic acid, succinic acid, and combinations thereof. A suitable combination is for example to use hydrochloric acid and a hydroxy acid, such citric acid, in which case the complex can be recovered in a solution composition containing sodium chloride and sodium citrate at a pH and osmolarity suitable for intravenous infusion.

Some precipitate may be formed during pH adjustment depending on the conditions used. Such precipitate can be removed by filtration.

Further adjustments of the composition can be made and other auxiliary substances may be added, such as tonicity modifiers, complexation-enhanging agents, stabilizers, and cryoprotectants, examples of which are given below. The composition can be sterile filtered.

The curcumin complex can be recovered from the solution or it can be subjected to further processing in solution without isolation.

During the manufacturing of the complex, curcumin and cyclodextrin can be contacted in different ways. A first method comprises the steps of making an alkaline cyclodextrin solution with a pH of at least pH 11, mixing curcumin with the alkaline cyclodextrin solution and, after dissolution, lowering the pH to below pH 8. This is a preferred method. Curcumin typically dissolves in a few minutes.

In a second method curcumin is first dissolved in alkaline solution at a pH of at least pH 11, the cyclodextrin is mixed with the alkaline curcumin solution, and after dissolution, the pH is lowered.

A third method comprises the steps of dissolving curcumin in an alkaline solution at a pH of at least 11, dissolving the cyclodextrin in a second solution, mixing the solutions, and lowering the pH.

In all of the above embodiments, curcumin used in a solid form can be wetted and degassed before mixing with the cyclodextrin solution.

An organic solvent, such as ethanol may be added to enhance the solubility of curcumin.

A suitable temperature for the contacting step is 2 - 40 ⁰ C, such as 15 - 30 ⁰ C and in particular 20 - 25 ⁰ C.

Cyclodextrins and other biological raw materials may contain bacterial endotoxins. Surprisingly, it was found that when curcumin was dissolved by the method of the present invention, in particular using the embodiment described in Example 1, a curcumin complex with less than 1 IU/ml endotoxins was obtained even when a commercial cyclodextrin was used, which contained about 100 IU/ml endotoxins when dissolved in pyrogen- free water at 100 g/1.

Thus, the method of the present invention is particularly beneficial in the manufacture of endotoxin- free curcumin complexes by eliminating endotoxins present in the biological starting materials used.

The recovered cyclodextrin complex of curcumin is stable in an aqueous solution composition for at least three months at room temperature. The concentration of the complex influences its stability in solution so that dilute solutions are less stable. It is therefore preferable to have a solution composition with a curcumin concentration of more than 1 mmol/1 and up to about 100 mmol/1, preferentially at least 5 mmol/1. A practical curcumin concentration is at least 10 mmol/1, such as 10 - 60 mmol/1.

The complex can be dried, for example by lyophilization, spray-drying, spray-freeze- drying, antisolvent precipitation, a process utilizing a supercritical or near supercritical fluid, or other methods known to those of ordinary skill in the art to make a powder, granular or other solid form.

The complex according to the present invention has a red color at neutral pH (pH of about 6.8 to 7.5, in particular about 7.4). Preferably the red colour is detectable at a curcumin concentration of 10 mmol/1 or more. This differentiates the complex from free curcumin and complexes of curcumin with other cyclodextrins, which are orange or yellow at neutral pH.

The finding that it is possible to obtain a water-soluble and stable cyclodextrin complex with an excellent yield of curcumin was surprising as in the prior art it has been considered that curcumin is rapidly hydrolyzed at alkaline pH (3). US Patent No. 4,999,205 describes a method for the manufacture of clear water-soluble curcumin complexes with improved light stability and tinctorial power. The method includes the steps of contacting a substrate and curcumin in an aqueous solution at a pH above 9, at which curcumin is present in its water-soluble red alkaline form, and then acidifying to drop the pH to below about 8, thereby complexing the curumin in its neutral yellow form with the substrate. The stability of curcumin was determined by absorption; however, it has been shown that the hydro lytic degradation products of curcumin have a similar absorption as curcumin making absorption an unreliable method for stability assessment of curcumin (3). In the present invention a reverse phase HPLC method is used for the determination of curcumin concentrations.

US Patent No. 4,999,205 mentions as substrates for curcumin complex formation water- soluble branched chain or cyclic polysaccharide and water-soluble or water-dispersible proteins. Cyclodextrins generally are mentioned as a substrate. In our comparative studies described in Example 2, we prepared a curcumin complex with gelatin essentially as described in US Patent No. 4,999,205. We also prepared curcumin complexes with non- etherified γ-cyclodextrins and ether derivatives of β-cyclodextrin under different conditions, including the conditions of the present invention. A considerable proportion of curcumin precipitated during lowering of the pH or storage of the other cyclodextrin complexes and the gelatin complex, and only low concentrations of soluble curcumin was obtained. The recovery of the added curcumin varied from less than 1% to 26% when other cyclodextrins were used, whereas more than 95% of curcumin was recovered in the cyclodextrin complex of the present invention. Water-soluble complexes with the other cyclodextrins were obtained only in the presence of clearly higher molar ratio of

cyclodextrin to curcumin than with the complex of the present invention. Furthermore, the other complexes were not stable during storage.

DE Patent Application No. 10233598 describes cosmetic or dermatological compositions containing curcumin and cyclodextrins, and in Example 2, an oil in water emulsion

(creme) containing curcumin and hydroxypropyl-γ-cyclodextrin is mentioned. The method of the manufacturing and the pH of the compositions are not described. From the scientific publications (5, 6, 7) and from our own experiments it is evident that curcumin does not form a water-soluble complex when it is contacted with hydroxypropyl-γ-cyclodextrin at the mass ratios described in the DE 10233598 and at a pH which could be used for dermatological compositions (pH 3-9). Instead, curcumin may be dissolved in the oil phase of the described compositions, which are not suitable for parenteral administration, unlike the compositions of the present invention.

It is therefore evident that the cyclodextrin complex according to the present invention is superior to the other cyclodextrin and protein complexes of curcumin known in the prior art by being soluble at much higher curcumin concentrations. Additionally, the molar excess of cyclodextrins to curcumin is clearly lower in the current complex than in the complexes with other cyclodextrins. Furthermore, the present complex has considerably better stability than the other complexes, also when exposed to ambient room light. Finally, the complex is essentially free of endotoxins. These properties are important for the pharmaceutical and other clinical and nutraceutical uses of the complex.

The present invention provides pharmaceutical compositions for the prevention and treatment of diseases and clinical conditions, in which curcumin has therapeutic efficacy. The compositions contain an effective amount of the cyclodextrin complex of curcumin together with auxiliary substances.

In many diseases, particularly in life-threatening conditions, it is necessary to give curcumin as an intravenous injection or infusion to achieve therapeutic concentrations in critical tissues. A suitable formulation for intravenous administration is at simplest the solution composition obtained after manufacturing of the cyclodextrin complex, when a sterile aqueous solution is manufactured using methods and conditions known to those with ordinary skill in the art. The solution composition contains at least one tonicity

modifier, such as sodium chloride, and preferentially a buffer. The buffer is preferentially a hydroxy acid or a salt thereof, such as citrate, lactate, malate, tartrate or gluconate.

Other auxiliary substances may be added, such as tonicity modifiers, complexation- enhancing agents, stabilizers, preservatives, antioxidants, chelating agents, and cryoprotectants. The osmolality of the solution is preferentially 240 - 600 mOsmol/1 and pH is at least about 4 and below 8, preferentially 4.0 - 7.6. The formulation may be filled aseptically into injection or infusion bottles, ampoules, bags, or syringes. It may be freeze- dried and stored in powder form until reconstitution before administration.

The formulation may be administered through different parenteral routes, such as intravenously, intravascularly, intra-arterially, subcutaneously, intramuscularly, intra- articularly, intraperitoneally, or intrathecally.

By the novel method a pharmaceutical curcumin formulation containing for example 20 mg/ml curcumin can be manufactured (Example 4). This makes it possible to administer as an intravenous infusion doses as high as 100 mg/kg in a feasible infusion volume, such as 350 ml to a 70-kg patient.

The cyclodextrin complex of curcumin can be also used for the manufacture of colloidal drug carrier systems of curcumin, such as liposomes and polymer based nanoparticles and microparticles. Particularly, the cyclodextrin complex of curcumin can be entrapped into liposomes, such as pegylated liposomes, for prolonged half-life in circulation and more efficient targeting to tumors. Methods for the entrapment of cyclodextrin complexes of hydrophobic drugs into liposomes have been recently described (8). The use of the cyclodextrin complex of curcumin results in the entrapment of curcumin in the aqueous space inside the liposomes, and higher curcumin concentrations and improved stability may be obtained.

A further application of the cyclodextrin complex of curcumin is the manufacture of pharmaceutical formulations for inhalation. Aqueous cyclodextrin solutions can undergo aerosolization at proper cyclodextrin concentrations and the resulting droplet-size is compatible with pulmonary deposition. For hydroxypropyl-γ-cyclodextrin a suitable concentration for aerosolization has been reported to be about 50 mmol/1 (9). Aerosol can

be generated by ultrasonic nebulizer for efficient dosing of curcumin into the lungs. An aqueous formulation for aerolization contains similar auxiliary substances as the solution for intravenous administration, and the concentration of the cyclodextrin complex is adjusted to an optimal concentration for aerolization. The cyclodextrin complex can also be used for the manufacture of an inhalation powder for administration of curcumin by a powder inhalation device. Pulmonary dosing not only results in higher concentrations of curcumin in the lungs but may be also used for systemic delivery of curcumin.

The present invention also provides pharmaceutical and nutraceutical compositions for oral administration of curcumin in the dosage form of oral solution, a tablet, a cap let, a pellet, a capsule, a granule, a pill, a powder or a sachet. The present invention further provides pharmaceutical compositions for topical administration of curcumin to skin and mucosal surfaces, including oral, gastroenteral, nasal, vaginal and rectal mucosae, eyes and ears, and for transmucosal delivery. The pharmaceutical form can be cream, gel, lotion, solution, ointment, paste, powder, granular form or transdermal patch. It can be liquid, semi- so lid or solid, and it can be mucoadhesive or bioadhesive. A buccal or nasal delivery system or a suppository for rectal administration can be manufactured. These pharmaceutical formulations contain the cyclodextrin complex of curcumin as an active ingredient together with auxiliary substances (excipients) depending on the dosage form. The choice of the excipients can be made based on the intended route of administration and pharmaceutical practice. The excipients may include solubility and complexation-enhancing agents, solvents, fillers, vehicles, coatings, disintegrants, flavorants, binders, buffers, chelating agents, foam control agents, emollients, humectants, lubricants, plasticizers, preservatives, antioxidants, thickeners, mucolytic, mucoadhesive or bioadhesive substances, or a combination thereof.

A complexation-enhancing agent can be added to enhance the complexation of curcumin with the cyclodextrin. Suitable complexation enhancing agents include one or more pharmacologically inert water soluble polymers, hydroxy acids, and other organic compounds typically used in liquid formulations to enhance the complexation of a particular agent with cyclodextrins. Water soluble natural polymers include polysaccharides such as inulin, pectins, algin derivatives and agar, and polypeptides such as casein and gelatin. Suitable water soluble semi- synthetic polymers include cellulose derivatives, such as methylcellulose, carboxymethylcellulose, hydroxyethyl cellulose,

hydroxypropyl cellulose, hydroxypropyl methylcellulose, hydroxyethyl ethylcellulose, hydroxypropyl ethylcellulose, and hydroxypropyl methylcellulose phthalate. Suitable water soluble synthetic polymers include polyoxyethylene derivatives, such as polyethylene glycols and polyvinyl derivatives, such polyvinyl alcohol, polyvinylpyrrolidone and polystyrene sulfonate, and various copolymers of acrylic acid, such as carbomer. Suitable hydroxy acids include citric acid, malic acid, lactic acid, and tartaric acid and others known to those of ordinary skill in the art.

Buffering agents include, by way of example and without limitation, the following acids and their sodium and potassium salts: acetic acid, adipic acid, citric acid, maleic acid, lactic acid, tartaric acid, fumaric acid, succinic acid, phosphoric acid, and gluconic acid. Suitable tonicity modifiers include for example glycerol, lactose, mannitol, dextrose, sodium chloride, sorbitol, sucrose and trehalose. Stabilizing agents include, for example, albumin, glycine and other amino acids, glycerol, mannitol, polyethylene glycol, propylene glycol, sucrose and others known to those of ordinary skill in the art. Preservatives, antioxidants and chelating agents include, for example, benzoic acid, benzyl alcohol, chlorhexidine gluconate, chlorobutanol, edetate (EDTA), pentetate, phenylethyl alcohol, sorbic acid, methyl, ethyl and propyl parabens, ascorbic acid, ascorbyl palmitate, retinyl palmitate, butylated hydroxyanisole, butylated hydroxytoluene, monothioglycerol, and propyl gallate. Cryoprotectants include for example glycerol, trehalose, propylene glycol, and polyethylene glycol.

Solubilizing agents include, by way of example and without limitation, alginic acid, carboxymethylcellulose, cellulose, glycerol, ethylene glycol, and propylene glycol. Suitable fillers include for example calcium carbonate, dibasic calcium phosphate, lactose, magnesium carbonate, magnesium oxide, lactose anhydrous, microcrystalline cellulose and mannitol. Examples of suitable binders include alginic acid, methylcellulose, and polyvinylpyrrolidone. Suitable lubricants are for example stearic acid, talc, sodium stearyl fumarate, glyceryl behenate, magnesium silicate, magnesium trisilicate and hydrogenated castor oil, and a mixture thereof. As the disintegrator, there are mentioned, for example, croscarmellose codium, crospovidone, starch, sodium starch glycolate, carboxymethyl cellulose, and microcrystalline cellulose. A glident can be for example colloidal anhydrous silica and talc. As coating agents, there are mentioned, for example, carboxymethylcellulose, copovidone, titanium dioxide.

It is obvious that many auxiliary substances or excipients serve more than one function and many other substances not mentioned here are known to those of ordinary skill in the art and can be used in the formulations of the present invention.

Diseases and clinical conditions, which can be treated with the pharmaceutical formulations containing the cyclodextrin complex of the present invention, include life- threatening diseases and clinical conditions such as various forms of cancer and leukemias, cardiovascular diseases such as myocardial infarction, stroke, sepsis, acute lung injury, acute liver failure, acute tubular necrosis, acute pancreatitis, graft versus host disease and graft rejection, and radiation injury.

The pharmaceutical compositions of the present invention can be further used for treatment or reduction of oral and gastrointestinal mucositis in a patient undergoing or preparing to undergo chemotherapy or radiotherapy

The pharmaceutical formulations of the present invention can be further used in the prevention and treatment of ischemia/reperfusion injury, which takes place in clinical conditions characterized by temporary decrease or complete stop of blood flow to one or several organs (ischemia) followed by restoration of blood flow (reperfusion). These clinical conditions include organ transplantations, thrombolytic therapy and other revascularization procedures, cardiovascular surgery such as cardiac surgery with or without cardiopulmonary bypass and angioplastic surgery, hemorrhagic shock and other forms of shock.

Further clinical conditions, which can be treated with the pharmaceutical formulations containing the cyclodextrin complex of the present invention include, but are not limited to, autoimmune diseases and inflammatory diseases such as rheumatoid arthritis, vasculitis and connective tissue disorders, inflammatory bowel diseases, nephropaties, hepatitis, liver injury and fibrosis, skin diseases such as psoriasis, scleroderma and skin cancers, lung injury and fibrosis, chronic obstructive pulmonary disease, asthma, degenerative and autoimmune diseases of the central nervous system such as Parkinson's disease, Alzheimer's disease and multiple sclerosis.

The administration of the pharmaceutical formulations of the present invention can be combined with other therapeutic treatments; for example, they can be combined with chemotherapy and radiation therapy of cancer and leukemias, as studies with cultured cells and animal models have demonstrated that curcumin may potentate the anticancer efficacy of chemotherapy and radiation therapy, while protecting normal tissues and cells from treatment-related toxicity.

In the prevention and treatment of diseases and clinical conditions, an effective dose of the cyclodextrin complex of curcumin is administered to the human or animal subject. Effective doses vary widely depending on the disease and clinical condition, route of administration, and dosage form. The doses are generally 0.1 - 300 mg/kg/day. Doses in oral administration are generally higher than in parenteral administration, such as 1 - 300 mg/kg/day. Intravenous doses are generally 0.5 - 100 mg/kg/day. Higher doses may be used in some clinical conditions (10, 11), while in some conditions, like sepsis (12) and muscle regeneration after traumatic injury (13), even lower doses of curcumin may be effective. In topical administration the doses vary depending on the surface area to be treated, and doses below 0.1 mg/kg/day may be used.

The present invention further provides a method for the protection of organs, tissues and cells during hypothermic preservation and perfusion, which comprises contacting the organs and cells with a preservation solution containing a cyclodextrin complex of curcumin. Curcumin protects organs and cells during hypothermic storage and perfusion from ischemia, hypothermic injury and oxidative stress. During rewarming and reperfusion curcumin protects the organs against reperfusion injury. The present invention makes it possible to add curcumin in a stable and water-soluble form to aqueous preservation and perfusion solutions, which is a prerequisite for the exploitation of curcumin's protective effects in the preservation of organs and cells.

By definition, "hypothermia" as used herein refers to temperatures below the body temperature, particularly below 35 ⁰ C. Organ transplants are typically stored between 10 ⁰ C and 0 ⁰ C. Within the scope of the present invention, "hypothermia" also refers to temperatures used in cryopreservation, i.e. preservation of cells and tissues in a frozen or vitrous state at temperatures below 0 ⁰ C.

According to the present invention, organs for transplantation are flushed with an aqueous solution containing a cyclodextrin complex of curcumin during harvesting. During preservation ex vivo, organs may be continuously perfused or, alternatively, maintained in cold after initial flush with a preservation solution containing the cyclodextrin complex of curcumin. Organs may be flushed before implantation with rinse solutions, such as

Ringer's solution, containing the cyclodextrin complex of curcumin. Tissues and cells are immersed in an aqueous solution containing the cyclodextrin complex of curcumin. Organs may also be perfused in situ with blood or a blood-free solution containing the cyclodextrin complex of curcumin, particularly for preservation of the heart during temporary cardiac arrest and heart surgery.

Curcumin concentrations effective in the protection of organs and cells are generally 0.5 to 250 μmol/1. A solution composition, which is added to the preservation, perfusion and storage solutions, contains similar auxiliary substances as the solution for intravenous administration. A powder formulation may be also used, which is reconstituted before use.

The present invention also comprises kits consisting of a first solution or powder formulation containing a cyclodextrin complex of curcumin and a second solution which are combined before use. The complex may be incorporated in medical devices, such as in a bag set used for preparation or treatment of blood cells, where it is can be stored in liquid or solid form and reconstituted before use.

A composition containing the cyclodextrin complex of curcumin can be added to conventional organ preservation and perfusion solutions. Such commercially available preservation solutions are exemplified by ViaSpan® (Barr Laboratories, Inc., NJ, and Bristol-Myers Squibb, NY, USA), Celsior® (SangStat, Inc.,CA, USA), KPS-1® (Organ Recovery Systems, Inc., IL, USA), Perfadex® (Vitrolife AG, Sweden), Custodiol® (Dr. Franz Kόhler Chemie GmbH, Germany, and Essential Pharmaceuticals, LLC, PA, USA), IGL-1® (Institut Georges Lopez, France), Polysol® (Doorzand Medical Innovations B.V., The Netherlands), SCOT (MacoPharma, France) and Plegisol® (Abbott Laboratories, IL, USA). Other substances, such as albumin, can be also added.

Methods used in the examples:

The concentration of curcumin was measured by reverse phase HPLC (high pressure liquid chromatography). 50 μl of the diluted sample was added to 450 μl acetonitrile and 500 μl of 0.5% potassium citrate, pH 3.0, was added. The separation was performed on a 4 μm Nova-Pak Cl 8 column, 150 x 3.9 mm (Waters, Milford, MA, USA). The mobile phase was composed of 0.5% citric acid adjusted to pH 3 with KOH and acetonitrile (55:45). A flow rate of 1.0 ml/min was used. UV was monitored at 256 nm. 4-Hydroxybenzophenon (Fluka) was used as an internal standard. The retention times of curcumin, demethoxycurcumin and bisdemethoxycurcumin were approximately 7.4, 6.8, and 6.2 min. Endotoxins were determined by the gel-clot method and the chromogenic turbidimetric method according to Ph. Eur. 2.6.14.

The following non- limiting examples illustrate the invention:

EXAMPLE 1. Manufacture of a water-soluble stable cyclodextrin complex of curcumin and a pharmaceutical formulation thereof

2-Hydroxypropyl-γ-cyclodextrin (CAVASOL W8 Pharma, Wacker Chemi, Germany) was dissolved to a concentration of 100 g/1 in 0.2 mo 1/1 sodium hydroxide solution at about 23 ⁰ C. Curcumin (Curcumin C3 Complex, Sabinsa, NJ, USA) was added to a concentration of 14 g/1. The solution was agitated and protected from light. After complete dissolution of curcumin, the pH was lowered to 6.1 by addition of a mixture of 0.62 mo 1/1 hydrochloric acid and 0.12 mo 1/1 citric acid. The solution was sterile filtered and filled aseptically into sterile vials. The composition of the product is shown in Table 1.

Table 1

EXAMPLE 2. Comparison of the cyclodextrin complex of the present invention with other cvclodextrin and gelatin complexes of curcumin.

Complex formation of curcumin with different cyclodextrins, including 2-hydroxypropyl- γ-cyclodextrin (HPγCD), 2-hydroxypropyl-β-cyclodextrin (HPβCD; CAVASOL W7 Pharma, Wacker Chemi), sulfobutylether-β-cyclodextrin (SBEβCD; CyDex, NJ, USA), and γ-cyclodextrin (γCD; Sigma Aldrich, Germany) was compared. First, 100 g/1 of HPγCD and HPβCD and 135 g/1 of SBEβCD were dissolved in 0.1 mo 1/1 sodium hydroxide, 8.8 g/1 of curcumin was added and the solutions were agitated. After complete dissolution of curcumin the pH was lowered to 7.0, and further to pH 5.0 in part of the solution, with 0.5 M citric acid. A 47 g/1 solution of γCD was also made in 0.1 mo 1/1 sodium hydroxide, curcumin was added to a concentration of 4.4 g/1 and agitated. After dissolution of curcumin, the pH was lowered to 7.0, and further to pH 5.0 in part of the solution, with 0.5 M citric acid. All solutions were clear and intense red at alkaline pH. During lowering of the pH, a considerable amount of yellow precipitate was formed in the other cyclodextrin solutions but not in the HPγCD solution. The precipitation was most extensive in the γCD solution. The other solutions turned orange yellow when pH was lowered below 8, whereas the HPγCD solution was red at pH 7.4. The solutions were sterile filtered and stored at room temperature for 1 week. The properties of the solutions are shown in Table 2.

A 2% gelatin solution (Sigma Aldrich) was adjusted to pH 10 with 1 mo 1/1 sodium hydroxide. Curcumin (C3) was dissolved in 0.1 mol/1 sodium hydroxide to a concentration of 9 mg/ml. The curcumin solution was added to the gelatin solution to provide a 5.5% loading of curcumin to gelatin (ratio of weight of curcumin to gelatin, US Pat. No. 4,999,205). A clear red solution was obtained. The pH was decreased to pH 7.0 and further to pH 5.0 in part of the solution with 0.1 M citric acid. A considerable amount of precipitate was formed when the pH was lowered. Yellow solutions were obtained, which were sterile filtered and stored at room temperature for 1 week. The properties of the solution are shown in Table 2.

Table 2

EXAMPLE 3. Stability of the cyclodextrin complex of curcumin

Curcumin complexes with HPγCD were made by dissolving different amounts of HPγCD in 0.1 mol/1 sodium hydroxide and adding different amounts of curcumin, thus giving different cyclodextrin/curcumin (CD/C) ratios. After dissolution of curcumin, the pH was lowered to different pH values with 0.5 mol/1 citric acid. The solutions were sterile filtered,

filled aseptically into vials and stored at room temperature protected from light. Curcumin concentration was determined by HPLC at the time points indicated in Table 3.

Table 3

* Storage time 2 months

EXAMPLE 4. Manufacture of a cyclodextrin complex of curcumin and a pharmaceutical formulation thereof containing 20 g/1 curcumin

2-Hydroxypropyl-γ-cyclodextrin was dissolved to a concentration of 205 g/1 in 0.2 mo 1/1 sodium hydroxide solution. Curcumin was added to a concentration of 25 g/1. The solution was agitated and protected from light. After complete dissolution of curcumin, the pH was lowered to 6.1 by addition of a mixture of 0.62 mol/1 hydrochloric acid and 0.12 mo 1/1 citric acid. The solution was sterile filtered and filled aseptically into sterile vials. The composition of the product is shown in Table 4.

Table 4

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