IE904088A1 - "Process for the production of aqueous mixed micelle solutions" - Google Patents

Abstract

Described is a method of producing aqueous solutions containing mixed micelles formed from lipids and salts of gallic acids and in which active substances insoluble or only slightly soluble in water may, if required, be solubilized. The method is characterized in that mixtures of (a) solutions containing, in a water-soluble organic solvent, the lipids, the free gallic acids and, optionally, the active substances which are insoluble or only slightly soluble in water and (b) solutions containing 0.05-3 equivalents, relative to the gallic acids, of bases and, optionally, isotonizing additives and/or water-soluble active substances are prepared, the organic solvent removed by ultrafiltration, freeze-drying, vacuum distillation or reverse osmosis and the mixture thus obtained diluted, if required, with aqueous phase.

Description

PROCESS FOR THE PRODUCTION OF AQUEOUS MIXED MICELLE SOLUTIONS Background of the Invention The invention relates to a process for the production of aqueous mixed micelle solutions, containing mixed micelles formed from lipoids and salts of bile acids, in which slightly water-soluble or water-insoluble active ingredients are optionally solubilized.

Processes for the production of such mixed micelle 10 solutions are previously known, for example, from German patent specification 27 30 570.

In the previously known processes, the mixed micelle solutions are produced by the lipoids, salts of bile acids and optionally slightly water-soluble or water-insoluble active ingredients being dissolved in an organic solvent (e.g. ethanol), and the solutions being concentrated by evaporation so that a lipid film forms on the vessel walls which is dissolved by aqueous solutions (Biochemistry 12, 1980, 602 ff. and 615 ff.; Naturforsch. 32c, 1977, 748 it.).

But this process is quite complex and can be transferred on an industrially usable scale only with considerable equipment.

In addition to this preferred process, a process is known, for example, from example 3 of patent specification 27 30 570 which was already mentioned, in which such mixed S0d Tfltt 0TF9-£t?2-£02<:ON Ί31 0NU13Z 31ΙΗΠ N3TUW:QI 8t?:fT 06,-60-(ΊΟΝ IE 904088 - 2 micelle solutions are produced by mixing components and stirring the mixture.

But this process not only has the drawback that it takes several days but it is seen in the reworking of this example — without active ingredient — that only greatly clouded solutions, which contain mixed micelles with an average diameter of about 340 nm, are obtained in this way.

Clear solutions with mixed micelles of an average diameter of about 10 nm cannot be obtained in this way. io summary of the Invention It has now been found that such clear aqueous solutions of mixed micelles can be produced in a simple way and in a short time by a process which is characterized in that mixtures are prepared from a) solutions, which contain lipids, free bile acids and optionally slightly water-soluble or water-insoluble active ingredients in a water-soluble organic solvent and b) solutions, which contain 0.05 to 3 equivalent bases and optionally isotonized additives and/or water-soluble active ingredients relative to the bile acids, the organic solvent is removed by ultrafiltration, freeze-drying, vacuum distillation or reverse osmosis, and the mixture obtained optionally is diluted with aqueous phase.

The process according to the invention can be performed by using the same bile acids as the previously known processes. Suitable bile acids are 5fl-cholanic-24-acid derivatives of the general formula in which R1 and R? as well as R3 and R4 jointly mean an oxo group, two hydrogen atoms, or a hydrogen atom and a hydroxy group, and X represents a hydroxy group or a grouping of the formula -NH-CH2-CO2H or -NH-(CH2)2-SO3H.

As suitable bile acids, there can be mentioned, for example: cholic acid, glycocholic acid, taurocholic acid, deoxycholic acid, glycodeoxycholic acid, taurodeoxycholic acid, chenodeoxycholic acid, glycochenodeoxycholic acid and taurochenodeoxycholic acid.

For the production of aqueous mixed micelle solutions, preferably 1 to 30 g and especially 2 g to 15 g of bile acid per 100 g of the aqueous solution containing optionally isotonized additives and water-soluble active ingredients is used.

For the production of aqueous mixed micelle solutions, the same lipoids can be used in the process according to the invention as in the previously known processes.

Suitable lipoids include, for example, monoglycerides, sulfatides, and especially phospholipids, such as sphingomyelins, plasmalogons, phosphatidylcholines, phosphatidylethanolaroinea, phosphatidylserines, phosphatidylinosites and cardiolipins, and also mixtures of - 4 these lipoids (Dr. Otto-Albert Neumueller: Roempps CheraieLexikon; Franck'sche Verlagshandlung, Stuttgart (DE) 2665, 3159, 3920 and 4045).

For the production of aqueous mixed micelle solutions, preferably 3 to 40% and especially 5 to 20% of lipoid per 100 g of the aqueous solution containing optionally isotonized additives and/or water-soluble active ingredients is used. The weight ratio between lipoid and bile acid is preferably 0.1;1 to 2:1 and especially 0.8:1 to 2:1.

Suitable bases for the production of aqueous mixed micelle solutions according to the process of the invention include alkali hydroxides, such as lithium hydroxide, potassium hydroxide and especially also sodium hydroxide, and organic nitrogen bases which form physiologically acceptable salts. Such nitrogen bases include, for example, ammonia, primary, secondary or tertiary amines, ethanolamine, diethanolamine, piperazine, morpholine, lysine, ornithine, arginine, Ν,Ν-dimethylglucamine, choline and especially N-methylglucamine and tris(hydroxymethyl)aminomethane. These bases are used according to the invention in an amount so that the solutions contain 0*05 to 3 equivalent of base and especially 0.5 to 2 equivalent of base relative to the bile acids.

Suitable water-soluble organic solvents include, for example, lower alcohols, such as methanol, ethanol, propanol or isopropanol, or acetone. These solvents are preferably used in amounts so that the resulting mixtures are also solutions. The known solvents can be removed both by vacuum distillation and by reverse osmosis (T. H. Heltzer, Advances in Parenteral Science 13, Filtration in the Pharmaceutical Industry, Marcel, Dekker Verlag New York, etc., 1st edition, - 5 72-74, 483-488 and 838-854; Chem.-Ing. Tech. (Chem. Eng. Tech.] £1, 1989, 535-544).

If the solvent is removed by freeze-drying, it is advisable to add 20 to 300 mg of a monosaccharide or disaccharide, such as glucose or galactose or a sugar alcohol, such as sorbitol or mannitol, to the solution ahead of time.

If the solvent is removed by ultrafiltration, a filter with an exclusion size of a maximum of 300,000 daltons is suitably used.

When the solvent is removed by reverse osmosis, which is already used industrially for water processing, the liquid to be removed, as is known, is removed through an asymmetrical membrane, which has no pores. Suitable membranes are, for example, those made from poly(dimethylsiloxane) or poly(vinyl alcohol) of about a 0.1 to 2 micron thickness which are applied to a sponge-like or tissue-like supporting layer. Suitable membrane modules are also capillary and tube modules or also plate modules or spirally wound modules. Relative to the development of solvent-selective membranes and their mode of operation, reference is made to the publication already mentioned in the journal Chem. Ing. Techn. 60, 1988, 590 ff.

The reverse osmosis can be used not only for removing solvents from aqueous dispersions, which have a higher vapor pressure than water, but it is also suitable for removing solvents with a lower vapor pressure than water, such as, for example, dimethyl formamide, dimethyl sulfoxide or acetonitrile.

After the removal of the solvent has been performed, the mixture obtained can optionally be diluted with an aqueous phase. In this case, it can be advisable to use an aqueous phase which contains a maximum of 10 ml of a neutralized bile acid and optionally additionally also isotonizing additives.

Suitable slightly water-soluble or water-insoluble active ingredients are preferably those whose watersolubility does not exceed 2% at room temperature. Such active ingredients are, for example, plant protecting agents, such as, poorly soluble insecticides or herbicides and especially poorly soluble pharmaceutically active ingredients.

Poorly water-soluble or water-insoluble pharmaceutical active ingredients of the following active ingredient groups are suitable, for example, for the production of the pharmaceutical agents according to the invention: Gestagenally effective steroid hormones such as, for example, 13-ethyl-17S-hydroxy-18,l9-dinor-17a-pregn-4-en-2yl-3-one (-levonorgestrel), i3-ethyl-17fi-hydroxy-18,19dinor-17tt-pregna-4,15-dien-20-yn-3-one (*gestodene) or 13ethyl-17fi-hydroxyll-methylene-l8,19-dinor-l7a-pregn-4-en20-yne (desorgestrel); estrogenically effective steroid hormones such as 3-hydroxy-l,3,5(10)-estratrien-17~one (-estrone) or l,9-nor-17e-pregna-l,3,5(10)-trien-20-yn3,17B-diol (ethinylestradiol).

Androgenically effective steroid hormones such as 176hydroxy-4-androsten-3-one (=testosterone) and its esters or 17B-hydroxy-lo-methyl-5a-androsten-3-one (=mesterolone).

Antiandrogenically effective steroid hormones such as 17a-acetoxy-6-chloro-lfl,2a-dihydro-3'H-cyclopropa[1,2]pregna-l,4,6-triene-3,20-dione (cyproterone acetate).

Corticoids such as 11B,17a,21-trihydroxy-4-pregnene3,20-dione (=hydrocortisone), llB,17a,21-trihydroxy-l,4pregnadiene-3,20-dione (-prednisolone), ιΐβ,ΐ7α-2ΐtrihydroxy-6a-methyl-1,4-pregnatriene-3,20-dione (-methylprednisolone) and 60-fluoro-llS,2i-dihydroxy-16aIE 904088 - 7 methyl-1,4-pregnadiene-3,20-dlone (=difluorocortolone).

Ergolines such as 3-(9,10-dihydro-6-methyl-8arergolinyl)-1,1-diethyl urea (=ergoline), 3-(2-bromo-9,10dihydro-6-methyl-8a-ergolinyl)-l,1-diethyl urea («bromoergoline) or 3-(6-methyl-8a-ergolinyl)-i,i-diethyl urea («terguride).

Antihypertensives such as 7a-acetylthio-17a-hydroxy-3oxo-4-pregnene-21-carboxylic acid- -lactone («spironolactone) or 7or-acetylthio-15fl, 16flmethylene-3-oxo-17a-pregna-l,4-diene-21,17-carbolactone («mespirenone).

Anticoagulants such as 5-[hexahydro-5-hydroxy-4-(3hydroxy-4-roethyl-l-octen-6-ynyl)-2(1H)-pentalenylidene))pentanoic acid (=iloprost).

Psychopharmaceutical agents such as 4-(3cyclopentyloxy-4-methoxy-phenyl-2-pyrrolidone («rolipram) and 7-chloro-l,3-dihydro-l-methyl-5-phenyl-2H-l,4benzodiazepin-2-one («diazepam).

Carotinoids such as α-carotene and β-carotene.

Liposoluble vitamins, such as vitamins of the vitamin A, vitamin D, vitamin E and vitamin K groups.

The β-carbolines are an especially preferred group, as they are described, for example, in European patent applications 234,173 and 239,667. As β-carbolines, there can be mentioned, for example, 6-benzoyloxy-4-methoxymethylB-carboline-3-carboxylic acid-isopropylester («becarnil) and -(4-chlorophenoxy)-4-methoxymethyl-fl-carboline-3carboxylic acid-isopropyl ester (=C1-Phocip).

The aqueous mixed micelle solutions produced according to the process of the invention can optionally contain isotonic additives to increase their osmotic pressure. Suitable additives are, for example, inorganic or organic salts or buffer substances, such as sodium chloride, - 8 phosphate buffer, citrate buffer, glycine buffer, citratephosphate buffer, TRIS-HCl buffer, maleate buffer, etc.; monosaccharides or disaccharides, such as glucose, lactose, saccharose; sugar alcohols, such as mannitol, sorbitol, xylitol or glycerine; or water-soluble polymers, such as dextran or polyethylene glycol.

These isotonized substances are usually added in concentrations so that the resulting aqueous mixed micelle solution exhibits an osmotic pressure of 5-1000 mosm, with Injection solutions of optimally 300 mosm.

Further, the aqueous mixed micelle solutions can contain additional water-soluble active ingredients to produce combination preparations. Examples of such combination preparations are mixtures of water-soluble and fat-soluble vitamins or preparations which contain watersoluble antibiotics, in addition to corticoids.

The micelles of this invention can be used conventionally, e.g., for pharmaceutical purposes, e.g., in accordance with German Patent 27 30 570, Acta Anaeethesiol. Scand. 1986, 337-340 and J. Pharm. Pharmacol. 1988, 85-88.

The aqueous mixed micelle solutions of this invention contain mixed micelles with an average diameter of 2 to 100 nm, preferably 3 to 50 nm. Especially in the case of solutions suitable for injection, the mixed micelles will optimally have an average diameter of 3 to 20 nm.

Since the lipoids and also some active ingredients are sensitive to oxidation, the process is suitably performed under an inert gas atmosphere, such as nitrogen or argon, and the aqueous mixed micelle solutions obtained are stabilized by adding antioxidants, such as sodium ascorbate, tocopherol or sodium hydrogen sulfite.

The process according to the invention has the advantage that on an Industrial scale, it is substantially simpler to perform than the previously known processes. The dissolving, mixing and vacuum distillation or reverse osmosis process steps required in its performance are industrially continuously performable and not costly.

Moreover, the process according to the invention has the advantage that the thermal stress of the components is less than in the previously known processes, especially so if the process of reverse osmosis is used to remove the solvent. After the production has been performed, the aqueous mixed micelle solution obtained can be sterilized by filtration and/or heat-sterilized at 100° to l40°c.

The following embodiments are used to explain the process according to the invention in more detail.

Without further elaboration, it is believed that one 15 skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

In the foregoing and in the following examples, all temperatures are set forth uncorrected in degrees Celsius and unless otherwise indicated, all parts and percentages are by weight.

The entire disclosures of all applications, patents and publications, if any, cited above and below, and of corresponding application Federal Republic of Germany P 39 38 030.0, filed November 13, 1989, are hereby incorporated by reference. - 10 EXAMPLES Example 1 400 ml of an aqueous solution, which contains 2.138 of sodium hydroxide, is introduced in a round-bottom flask.

Then, it is mixed with 100 ml of an ethanol solution, which contains 45 g of phospholipid ((phospholipon 100 L, manufacturer A. Nattermann & Cie., DE-5000 Cologne) and 27.1 g of glycocholic acid. A clear mixture results slightly with yellowish coloring and a pH of 6.5.

The ethanol is removed by reverse osmosis, by the solution being concentrated from 500 ml to 250 ml in an apparatus for the reverse osmosis (Membra-Fil P-28. Buechi company, Goeppingen, Membrane DRC-1000). The pressure is 35 bars. In a second step, the concentrate is diluted with a 3.5 mM solution of neutralized glycocholic acid to the initial volume. The mixed micelle formulation obtained then contains less than 0.01 mg/ml of ethanol.

The composition is as follows: Phospholipon: Manufacturer Nattermann AG, DE-5000 Cologne 90.0 mg Glycocholic acid: 52.1 mg Sodium hydroxide: 4.3 mg Water to 1.0 ml pH: 6.6 Example 2 800 ml of an aqueous solution with 2.8 g of potassium hydroxide is mixed with 120 ml of an ethanol solution, which contains 45 g of phospholipon and 27 g of glycocholic acid.

A clear solution results whose pH is adjusted to 6.5 with 0.1 N potassium hydroxide solution. 18 g of sorbitol is added to this solution and stirred to complete dissolution.

The mixed micelle solution containing ethanol is - 11 converted in an ultrafiltration unit (Amicon GmbH, DE 8510 Witten; Type DC 2, Membrane: HIP 30-20). It is ultrafiltered at a membrane differential pressure of at most 1 bar. The volume of the removed ultrafiltrate is continuously replaced by 10 mM neutralized glycocholic acid solution. If the ultrafiltrate volume is 2.5 1, the continuous supply is interrupted and the mixed micelle solution is concentrated from 1 1 to 500 ml.

The formulation has the following composition: Phospholipon: 88.9 mg Glycocholic acid: 58.0 mg Potassium hydroxide: 6.4 mg Water: to 1.0 ml pH: 6.8 Example 3 Under the conditions of example 2, a mixed micelle solution is produced, with the difference, however, that the aqueous solution additionally contains 50 mg of sodium EDTA and the ethanol solution additionally contains 580 mg of active ingredients (Cl-Phocip).

The mixed micelle formulation obtained has the following composition: Phospholipon: 89.2 mg Glycocholic acid: 52.3 mg Potassium hydroxide: 6.1 mg Cl-Phocip: 1.01 mg Water: to 1.0 ml pH: 6.7 The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples. - 12 From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.

Claims (27)

WHAT IS CLAIMED IS:

1. A process for the preparation of an aqueous solution of mixed micelles containing a lipid and a salt of a bile acid, comprising mixing (a) a solution comprising a lipid and a free bile acid in a water-soluble organic solvent with (b) a solution comprising 0.05 to 3 equivalents, relative to the bile acid, of a base, and removing said organic solvent.

2. A process of claim 1, wherein solution (a) further contains an active agent which is sparingly soluble or insoluble in water.

3. A process of claim 1, wherein solution (b) further contains an isotonizing additive and/or water soluble active agent.

4. A process of claim 2, wherein solution (to) further contains an isotonizing additive and/or water soluble active agent. - 14

5. A process of claim 1, wherein the organic solvent is removed by ultrafiltration, freeze-drying, vacuum distillation or reverse osmosis.

6. A process of claim 1, further comprising diluting with an aqueous phase the mixture obtained after removing the organic solvent.

7. A process of claim 1, wherein solution (a) is diluted such that the mixture obtained with solution (b) is also a solution.

8. A process for the preparation of an aqueous mixed micelle solution according to claim 1, wherein the bile acid is a 5B-cholanic-24-acid derivative of the formula wherein R 1 and R 2 R 3 and R 4 are two hydrogens, hydrogen jointly are oxo, are two hydrogens, hydrogen jointly are oxo, and is hydroxy, -NH-CH 2 -CO 2 H or and hydroxy, or and hydroxy, or -nh-(ch 2 ) 2 -so 3 h. - 15

9. A process of claim l, wherein the lipid is a phospholipid.

10. A process of claim 1, wherein the base is sodium hydroxide or potassium hydroxide.

11. A process of claim 2, wherein the active agent which is sparingly soluble or insoluble in water is a pharmaceutical active agent.

12. A process of claim 4, wherein the active agent which is sparingly soluble or insoluble in water is a pharmaceutical active agent.

13. A process of claim 11, wherein the pharmaceutical active agent is a β-carboline.

14. A process of claim 12, wherein the pharmaceutical active agent is a β-carboline.

15. A process of claim 2, wherein the resultant micelles have an average diameter of 3 to 50 nm.

16. A process of claim 11, wherein the resultant micelles have an average diameter of 3 to 50 nm.

17. A process for the preparation of an aqueous solution of mixed micelles containing a lipid and a salt of a bile acid, comprising removing organic solvent from a solution formed by mixing (a) a solution comprising a lipid and a free bile acid in a water-soluble organic solvent - 16 with (b) a solution comprising 0.05 to 3 equivalents, relative to the bile acid, of a base.

18. A solution of aqueous mixed micelles prepared by a process of claim 1.

19. A solution of aqueous mixed micelles prepared by a process of claim 2.

20. A solution of aqueous mixed micelles prepared by a process of claim 11.

21. A solution of aqueous mixed micelles prepared by a process of claim 13.

22. A solution of claim 21, wherein the β-carboline is 6-benzoyloxy-4-methoxymethyl-fi-carboline-3~carboxylic acidisopropyl ester or 5-(4-chlorphenoxy) -4-methoxymethyl-flcarboline-3-carboxylic acid-isopropyl ester.

23. suitable A solution of for injection. claim 19, which is in a form

24. A solution of claim 20, which is in a form suitable for injection.

25. A solution of aqueous mixed micelles containing a lipid and a salt of a bile acid, substantially free of thermally stressed components, wherein the mixed micelles have an average diameter of 3 to 20 nm. -16a

26. A process substantially as hereinbefore described with reference to the Examples.

27. A solution of aqueous mixed micelles whenever prepared by a process as claimed in any of claims 1 to 17 or 26.