Method for obtaining a natural mixture of conjugated equine estrogens depleted in non-conjugated lipophilic compounds

1. A method for obtaining a natural mixture of conjugated equine estrogens depleted in non-conjugated lipophilic compounds selected from the group consisting of non-conjugated flavonoids, non-conjugated isoflavonoids and non-conjugated norisoprenoids, said method comprising:

a) subjecting an aqueous initial phase, selected from the group consisting of

(i) an aqueous solution of a natural mixture of conjugated estrogens from pregnant mares' urine already depleted in phenolic urine contents comprising phenol, cresol and dihydro-3,4-bis[(3-hydroxyphenyl)methyl]-2(3H)-furanone and obtained by solid-phase or liquid-liquid extraction;

(ii) an aqueous concentrate of a natural mixture of conjugated estrogens from pregnant mares' urine already depleted in phenolic urine contents comprising phenol, cresol and dihydro-3,4-bis[(3-hydroxyphenyl)methyl]-2(3H)-furanone and obtained by solid-phase or liquid-liquid extraction;

(iii) a concentrate of pregnant mares' urine liquid, and

(iv) pregnant mares' urine concentrate, freed from mucilaginous substances and solids by mechanical separation methods, or a concentrated urine retentate obtained by filtration,

to a liquid-liquid extraction with a sufficient quantity of an organic solvent extracting agent which is at most only slightly miscible with water thereby extracting non-conjugated lipophilic compounds, and subsequently separating a resulting aqueous phase, whereby the organic solvent extracting agent is selected from the group consisting of straight-chained, branched or cyclic C 4 -C 10 alcohols, C 2 -C 10 esterified acids, C 3 -C 10 aldehydes, C 4 -C 10 ketones, C 2 -C 10 ethers, C 3 -C 6 nitriles and C 1 -C 3 haloalkanes and mixtures of the aforementioned solvents;

b) optionally repeating method step (a) with the resulting aqueous phase;

c) recovering an aqueous phase containing the natural mixture of conjugated estrogens depleted in non-conjugated lipophilic compounds selected from the group consisting of non-conjugated flavonoids, non-conjugated isoflavonoids and non-conjugated norisoprenoids;

d) distilling the recovered aqueous phase to remove residue of the organic solvent extracting agent; and

e) retaining the distilled aqueous phase from step d) as a starting material for the preparation of medicaments.

2. A method according to claim 1 , wherein said extracting agent is immiscible with water.

3. A method according to claim 1 , wherein the aqueous initial phase in method step a) comprises (i) an aqueous solution of a natural mixture of conjugated estrogens from pregnant mares' urine already depleted in phenolic urine contents, or (ii) an aqueous concentrate of a natural mixture of conjugated estrogens from pregnant mares' urine already depleted in phenolic urine contents.

4. A method according to claim 1 , wherein the extracting agent is selected from the group consisting of C 1 -C 4 -alkyl acetates, hexanol, diethyl ether, methylene chloride, methyl tert.-butyl ether and mixtures of two or more of the aforementioned solvents.

5. A method according to claim 4 , wherein the extracting agent comprises a C 1 -C 4 -alkyl acetate.

6. A method according to claim 5 , wherein the extracting agent is ethyl acetate.

7. A method according to claim 1 , wherein in method step (a) the aqueous initial phase is adjusted to a pH value in the range from 4 to 12.

8. A method according to claim 7 , wherein the pH value in step (a) is in the range from 4.0 to 7.0.

9. A method according to claim 8 , wherein the pH value in step (a) is in the range from 4.0 to 6.0.

10. A method according to claim 9 , wherein the pH value in step (a) is in the range from 4.7 to 5.3.

11. A method according to claim 1 , wherein in method step (a) the volume ratio of the aqueous initial phase to the extracting agent lies in the range from 5:1 to 1:3.

12. A method according to claim 11 , wherein the volume ratio of the aqueous initial phase to the extracting agent lies in the range from 2:1 to 1:2.

13. A method according to claim 1 , wherein in method step (b) the volume ratio of the aqueous initial phase obtained from step (a) to the extracting agent lies in the range from 20:1 to 1:1.

14. A method according to claim 13 , wherein in step (b) the volume ratio of the aqueous initial phase obtained from step (a) to the extracting agent lies in the range from 10:1 to 2:1.

15. A method according to claim 3 , wherein the depletion in phenolic urine contents is obtained by solid-phase extraction on a non-ionic semipolar adsorption resin or on a hydrophobized silica gel.