More particularly, the present invention relates to a liquid composition for use in soft capsule preparations, which contains various surfactants for solubilization and oils, and also to a method for producing the same.

Cyclosporin is a specific macromolecular cyclic oligopeptide compound (molecular weight: 1202.64) in which 11 poly-N-methylated amino acids are bonded with each other to form a cyclic peptide structure. Cyclosporin is known as showing useful pharmacological activities, particularly immuno-suppressive activity and anti-inflammatory activity.

Cyclosporin, which was first discovered, is a spontaneous fungus metabolite isolated from Tolypocladium inflatum Gams, which is generally known as cyclosporin A and most frequently used. Currently, cyclosporin is produced in large quantities by a synthetic or semi-synthetic process.

Cyclosporin has been used to inhibit biological immune responses, which often occur upon the transplantation of tissues or organs, such as the heart, lungs, liver, kidney, pancreas, marrow, skin and cornea, and particularly the transplantation of exogenous tissues or organs. Moreover, cyclosporin is effective in inhibiting hematological disorders, such as anemia, various autoimmune diseases, such as systemic lupus erythematosus and idiopathic malabsorption, and inflammatory disorders, such as arthritis and rheumatic disorders. In addition,

cyclosporin is also useful for treatment of protozoal disorders, such as malaria and schistosomiasis, and particularly recently, it is used in anticancer therapy.

In spite of the usefulness of cyclosporin for the inhibition of the biological immune response caused by the transplantation of tissues or organs and for the treatment of autoimmune disorders, cyclosporin has been used in a very limited manner. This is because cyclosporin shows high lipophilicity and thus very low solubility in water so that it has a property in that it is well dissolved in organic solvents, such as alcohol, ether, chloroform and the like. Cyclosporin is known as showing a very low bioavailability of about 10-60% upon oral administration due to solubility in water. Furthermore, since the bioavailability of cyclosporin may greatly vary depending on the conditions of each patient, it is difficult to maintain the effective therapeutic concentration of cyclosporin, and also cyclosporin shows side effects, such as nephrotoxicity. As a result, many studies have been actively conducted in an attempt to discover a preparation suitable for the effective oral administration of cyclosporin, which can provide a suitable uniform dosage and increased bioavailability.

Background Art As methods for the formulation of cyclosporin difficultly soluble in water into a preparation for oral administration, methods of formulating cyclosporin into an emulsion are most frequently used, of which typical method is disclosed in U. S. patent No. 4,388, 307 which describes a liquid composition of cyclosporin containing ethanol.

According this US patent, cyclosporin is formulated with a carrier comprising an ethanol as a co-surfactant, olive oil as a vegetable oil, and a trans-esterification product of natural vegetable oil triglyceride and polyalkylene glycol as a surfactant, thereby producing a liquid composition.

However, the produced liquid composition is administered as an aqueous dilution, which makes it very difficult to adapt the subject to its administration and to provide a uniform dosage for oral administration. Thus, in order to overcome the inconvenience of diluting the liquid composition in water prior to its administration, the liquid composition of an emulsion state is formulated as a soft capsule preparation before marketing. In this case, the soft capsule preparation of cyclosporin contains ethanol because of the solubility requirement of cyclosporin, in which the ethanol is volatile even at room temperature and thus may permeate the gelatin shell of the capsule preparation. In order to prevent volatilization of the ethanol from the soft capsule preparations during storage and distribution, the soft capsule preparations can be packed in a special packing material, such as an aluminum foil blister package.

Recently, it has been possible to develop a cyclosporin preparation, which is stable during the storage period and further shows little or no change in biological availability and its difference between individual subjects, so that the biological effect of cyclosporin can be uniformly maintained. One of preparations developed for this purpose is disclosed in Korean patent laid-open publication No. 93-113, and this preparation is sold under the trademark Sandimmun Neoral. However, in this preparation, since ethanol is also added, changes in storage stability and ethanol content are caused in the

same manner as in the prior ethanol-containing preparation so that the soft capsule is depressed or an emulsion phase becomes unstable, and thus, recrystallization of main components can occur. Moreover, Korean patent laid-open publication No. 90-12625 discloses a cyclosporin galen preparation comprising cyclosporin, fatty acid monoester, a diluent and a carrier, but this preparation is disadvantageous in that it shows reduced stability since the surfactant used in this preparation has very strong hygroscopicity. Japanese patent No. 193129/1987 discloses a technique of producing a solid dispersion using sucrose, sorbitol, urea, cellulose acetate phthalate as an enteric <BR> soluble base, and hydroxypropylmethylcellulose, etc. , but this is also insufficient to solve the problems. Moreover, Korean patent publication No. 93-6430 discloses a method of solubilizing cycrosporin by liposome. However, in this method, it may be impossible to formulate cyclosporin due to an increased dosage of cyclosporin, and also in mass production, various problems can occur.

Disclosure of Invention Accordingly, the present inventors have conducted many studies in an attempt to provide a composition where cyclosporin is pharmaceutically highly stable. As a result, we have found that when cyclosporin is formulated with a suitable mixture of various surfactants and oils and particularly co-surfactants, the above-mentioned stability requirement can be satisfied. On the basis of this point, the present invention was perfected.

The present invention provides a soft capsule preparation containing a self-emulsifying liquid

composition having a HLB value of 6-10, in which the composition comprises cyclosporin as an active ingredient, polyethylene glycol and propylene glycol as hydrophilic components, a mixture of an esterified compound of fatty acid and monovalent alkanol, middle-chain fatty acid triglyceride and fatty acid monoglyceride, as an oil component, and a surfactant having a hydrophilic lipophilic balance (HLB) value of 10-17. In another aspect, the present invention provides a method of producing the soft capsule preparation.

More specifically, the present invention provides a soft capsule preparation comprising cyclosporin as an active ingredient, hydrophilic component polyethylene glycol and propylene glycol serving as main solvent components, an oil component, and Cremophor as a hydrophobic surfactant, and also provides a method of producing the same.

The present invention is to produce a self-emulsified liquid cyclosporin preparation, which shows a reduced change in composition according to the passage of time and also excellent storage stability, and contains cyclosporin as an active ingredient, polyethylene glycol and propylene glycol as hydrophilic components, an oil component and a surfactant. In order to formulate this cyclosporin- containing liquid composition into a soft capsule preparation, a specially designed gelatin shell needs to be used. If the composition is formulated using a gelatin shell containing glycerin as a plasticizer, glycerin present in the shell of the capsule will be introduced into the liquid composition, so that an emulsified state of the composition will be changed to remarkably reduce the solubility of cyclosporin, thereby causing the problem of

the precipitation of cyclosporin.

For this reason, the self-emulsifying composition produced in the present invention utilizes a gelatin capsule shell containing no glycerin while ethanol as a volatile solvent is not used in the present invention, so that there is produced a soft capsule preparation which shows high stability and thus little or no aging during its storage period.

More specifically, the present invention relates to a cyclosporin-containing soft capsule preparation, which contains a composition containing cyclosporin as an active ingredient, hydrophilic polyethylene glycol and propylene glycol as main solvent components, a mixture of an esterified compound of fatty acid and monovalent alkanol, fatty acid monoglyceride and medium-chain fatty acid, as an oil ingredient, and a surfactant with a HLB value of 10-17.

As described above, cyclosporin used as pharmaceutically active ingredient is a cyclic oligo- peptide compound having immunosuppressive and anti- inflammatory activities. Examples of cyclosporin that can be used in the present invention include cyclosporin A, B, C, D and G. Among these substances, it is most preferred to use the cyclosporin A whose clinical utility and pharmacological properties were most well established in the prior art.

As the co-surfactant that is the second essential component of the liquid composition according to the present invention, there are used hydrophilic component polyethylene glycol and propylene glycol, which show reduced permeability to a gelatin capsule shell and also high solubility in cyclosporin, which is difficultly soluble in water. As the hydrophilic component

polyethylene glycol, although there may be used any polyethylene glycol which can be liquefied, it is preferred to use polyethylene glycol with a molecular weight of 200- 600, and most preferably, polyethylene glycol 400 with a molecular weight of 400.

The weight ratio between cyclosporin, polyethylene glycol and propylene glycol is advantageously 1: 1-10: 1-10 in view of the solubility of the active ingredient.

The third essential component of the liquid composition according to the present invention is an oil component. As the oil component that can be used in the present invention, there is an oil mixture of an esterified compound of fatty acid and monovalent alkanol, medium-chain fatty acid triglyceride (if any) and fatty acid monoglyceride. Preferred examples of the esterified compound of fatty acid and monovalent alkanol include an esterified compound of fatty acid with 8-20 carbon atoms and monovalent alkanol with 2-3 carbon atoms, for example, isopropyl myristate, isopropyl palmitate, ethyl linolate, ethyl oleate, with an esterified compound of linoleic acid and ethanol being particularly preferable. Also, the medium-chain fatty acid triglyceride includes saturated fatty acid triglyceride having 8-10 carbon atoms, and preferably, caprylic/caprylic acid triglyceride as vegetable oil triglyceride of saturated fatty acid.

Meanwhile, fatty acid monoglyceride that can be used as the oil component of the composition according to the present invention includes fatty acid monoceride having 18-20 carbon atoms, and more preferably, oleic acid monoglyceride.

In addition, the third essential component includes vegetable oil, such as soybean oil, olive oil, corn oil, coconut oil or a mixture of two or more thereof.

In the self-emulsifying micro-emulsion according to the present invention, the oil component is used at the ratio of 0.1-2 parts by weight, and preferably 0.1-1 part by weight, relative to one part by weight of cyclosporin.

In the oil mixture used as the oil component according to the present invention, the mixing ratio between monovalent alkanol and medium-chain triglyceride (if any) is generally 1: 0.1-1, and preferably 1: 0.1-0. 5, on the basis of weight.

The weight ratio between cyclosporin, medium-chain fatty acid and monovalent alkanol is preferably 1: 0.1-1 : 0.1-1, in view of the formation of an emulsion.

The fourth essential component contained in the composition according to the present invention is a surfactant. Among pharmaceutically acceptable surfactants allowing formation of a stable micro-emulsion by emulsifying of the lipophilic component cyclosporin- containing hydrophilic component consisting of the oil component and the co-surfactant, in water, any surfactant having a HLB value of 10-17 may be used in the present invention. Preferred surfactants include a polyoxyethylene product of hydrogenated vegetable oil, namely, polyoxyl hydrogenated castor oil, polyoxyethylene-sorbitan-fatty acid ester and the like, for example, NIKKOL HCO-50, NIKKOL HCO-40, NIKKOL HCO-60, TWEEN 20, TWEEN 21, TWEEN 40, TWEEN 60, TWEEN 80, and TWEEN 81, etc. The surfactants that is particularly preferable for use in the composition of the present invention include the trademark Cremophor RH40 having an acid value of less than 1, a saponification value of about 50-60, a hydroxyl value of about 60-80, and a pH (5%) of 6.0-7. 0, the trademark Cremophor-EL having an acid value of less than 2, a saponification value of about 65-70, a hydroxyl value of about 65-78, and a pH (5%) of 6.0-8. 0,

polyoxyethylene 20 sorbitan monolaurate commercially available under the trademark Tween 20, and polyoxyethylene 80 sorbitan monooleate commercially available under the trademark Tween 80. Although these surfactants may be used alone, they are preferably used in the form of a mixture of two or more thereof. In the composition of the present invention, the surfactant is present at the weight ratio of 1-10 parts by weight, and preferably 2-8 parts by weight, relative to one part by weight of cyclosporin. When a mixture of two surfactants consisting of polyoxyethylene 40 hydrogenated castor oil and polyoxyethylene 20 sorbitan monolaurate is used, the mixing ratio of polyoxyethylene 40 hydrogenated castor oil to polyoxyethylene 20 sorbitan monolaurate is preferably 1: 0.1-5, and more preferably 1: 0.5-2.

In view of the stability of the composition, it is particularly preferred that cyclosporin, polyoxyl hydrogenated caster oil 40, polyoxyl hydrogenated caster oil EL, polyoxyethylene 20 and polyoxyethylene 80 are present at the weight ratio of 1: 1-10: 1-10: 0.1-1 : 0.1-1 in the composition of the present invention.

In the composition of the present invention, the cyclosporin, the solvent component, the oil component, and the surfactant are present at the weight ratio of 1: 1- 10: 0.1-10 : 1-10, and preferably at the weight ratio of 1: 1- 5: 0.1-0. 6: 2-8. The cyclosporin, polyethylene glycol, propylene glycol, the oil component and the surfactant are present at the weight ratio 1: 1-10: 1-10: 0.1-1 : 0.1-10, and preferably 1: 1-2: 1-5: 0.1-0. 6: 0.1-7, in view of the stability of the preparation. In addition, compositions according to the present invention, which are illustrated in Examples below, can be regarded as preferred additional

compositions.

Since the soft capsule preparation according to the present invention contains no ethanol as a volatile solvent of low boiling point, it is pharmaceutically stable and also allows achievement of the desired end, such as the improvement of the bioavailability of cyclosporin. However, it cannot be produced with productivity by a shell formulation and producing method of conventional soft capsule preparations. In other words, when a general capsule shell containing glycerin and liquid sorbitol as plasticizers are used in the capsule formulation as in the prior art, there is caused a serious problem in that an emulsified state of the emulsion pre-concentrate is changed due to the inflow of glycerin and liquid sorbitol so that the solubility of cyclosporin is significantly reduced, thereby occurring the precipitation of cyclosporin from the emulsion. For this reason, in the present invention, a capsule shell composition containing a mixture of polyethylene glycol and propylene glycol as a plasticizer was used in preparing the self-emulsified content without using glycerin and sorbitol, so that there could be obtained a more stable soft capsule preparation showing no precipitation.

Best Mode for Carrying Out the Invention As polyethylene glycol serving as a plasticizer, there is preferably used polyethylene glycol having a molecular weight of 200-600, and more preferably, polyethylene glycol 300 or 400. The mixture of polyethylene glycol and propylene glycol, which is used as a plasticizer in the shell formulation of the soft capsule preparation according

to the present invention, is preferably used at the ratio of 0.1-0. 6 parts by weight, and more preferably 0.3-0. 5 parts by weight, and most preferably, 0.3-0. 4 parts by weight, relative to one part by weight of gelatin used in the shell. Moreover, in the mixture of polyethylene glycol and propylene glycol as the plasticizer, propylene glycol is preferably present at the ratio of 1-10 parts by weight, and more preferably 2-7 parts by weight, and most preferably 3-6 parts by weight, relative to one part by weight of polyethylene glycol.

In producing the soft capsule preparation according to the present invention, a main solvent (co-surfactant), an oil component and a surfactant are first uniformly mixed and then gently warmed to about 60 °C such that they are sufficiently mixed and dissolved. After lowering the temperature to 50 °C, cyclosporin is added to the resulting solution, and the mixture is stirred such that cyclosporin is dissolved. The resulting concentrate is introduced into a soft capsule encapsulation machine intact or after subjecting to a required treatment process.

The present invention will hereinafter be described in further detail by examples. It should however be borne in mind that the present invention is not limited to or by the examples.

Examples 1-4 and Comparative Example Components other than cyclosporin as an active ingredient and oils among components given Table 1 below are thoroughly mixed while warming to about 50-60 °C, and stirred until they become clear. Then, oils are added to the resulting solution and completely mixed with stirring

in the same manner. Then, cyclosporin is added slowly to the resulting mixture in such a manner that bubbles do not occur. At about 50 °C, the resulting material containing cyclosporin is stirred until it becomes a completely clear liquid. This gives a self-emulsifying liquid composition for use in the production of a soft capsule preparation.

Table 1: Self-emulsifying liquid compositions containing cyclosporin according to Examples 1-4 and Comparative Example Example Component Comparative 1 2 3 4 Example Cyclosporine A 25 25 25 25 25 polyethylene 35 50 125 125 105 glycol Cremophor RH4û 100 115 125 2û 105 Cremophor EL 50 50-105- TWEEN 20 10 25 10 5 10 TWEEN 80 10 15-5- Medium-chain 5 10 10 5 5 triglyceride isopropyl 15 15 5 5 myristate propylene glycol 50 25-5- ethanol---20 50 TOTAL 300 330 300 320 300 Test Example The soft capsule preparations produced according to

the present invention (see, Table 1) were stored at room temperature. During this storage period, whether the precipitation of its content occurs or not was observed.

The results are given in Table 2 below. As can be seen in Table 2, the content of the soft capsule preparation produced according to the present invention did not show its precipitation and a poorly emulsified state. On the other hand, when the emulsified state is poor as in Comparative Example, crystals started to be formed after about 3 days, and the content was mostly crystallized after about one month.

Table 2: Stability of content of capsule preparations according to shell formulation Shell Just after After 3 days After 10 After 30 After 60 After 180 formulation encapsulation days days days days Comparative ++ +++ ++++ +++++ Example Example 1 0 0 0 0 0 0 Example 2 0 0 0 0 0 0 Example3 0 0 0 ++ Example 4 0 0 0 + ++ ++ Note: 0: stable state of content; + : poorly emulsified state of content; ++: formation of fine precipitates; and +++: formation of precipitates Example 5 In order to produce a self-emulsifying soft capsule preparation containing cyclosporin, the composition of Example 1 was encapsulated with a shell formulation given in Table 3. A change in properties of the content of the soft capsule preparation caused by the inflow of glycerin

used as a placticizer in the encapsulation was observed.

The results are given in Table 4 below.

Table 3: Shell formulation of cyclosporin-containing soft capsule Component Control formulation Formulation of Example Gelatin 20 20 Purified water 20 20 Propylene glycol-5 Polyethylene glycol 3.2 1.5 Glycerin 6. 8 Preservative agent 0.08 0.08 Table 4: Stability of content of capsule according to shell component

Shell Just after After 3 After 10 After 30 After 60 After 180 formulation encapsulation days days days days days Control 0 0 0 + ++ +++ formulation Formulation 0 0 0 0 0 0 of Example

Industrial Applicability As described above, the present invention allows production of the self-emulsifying liquid composition having a HLB value of 6-10 without using ethanol, the self- emulsifying liquid composition comprising cyclosporin as an active ingredient, polyethylene glycol and propylene glycol

as hydrophilic components, an esterified compound of fatty acid and monovalent alkanol as an oil component, and a surfactant having a HLB value of 10-17. Moreover, according to the present invention, the cyclosporin- containing gelatin capsule preparation can be obtained by forming the gelatin capsule shell on the liquid composition without using glycerin. Furthermore, the soft capsule preparation of the present invention is a very stable preparation showing no formation of pharmaceutical precipitation therein and advantageous in that it is administered in a simple and easy way.