Pharmaceutical composition with improved storage stability and method for preparing the same

1. A method for preparing a pharmaceutical composition, comprising

(a) purifying an amphiphilic block copolymer comprising a hydrophilic block (A) and a hydrophobic block (B);

(b) dissolving one or more poorly water-soluble drugs selected from the group consisting of paclitaxel and docetaxel, and the purified amphiphilic block copolymer obtained in step (a) in an organic solvent; and

(c) adding an aqueous solvent to the solution obtained in step (b) to form polymeric micelles,

wherein the amphiphilic block copolymer is purified by sublimation,

wherein the sublimation is conducted at a temperature condition of from 80° C. to 100° C. and under a pressure condition of a vacuum degree of 10 torr or less,

wherein the hydrophilic block (A) is polyethylene glycol or monomethoxy polyethylene glycol, and the hydrophobic block (B) is polylactide, polyglycolide or a combination thereof; and

wherein the pharmaceutical composition contains, when stored at 40° C. for 6 months, a related compound represented by the following Formula 1 in an amount of less than 0.58 part by weight, based on 100 parts by weight of the initial amount of the poorly water-soluble drug:

wherein

R 1 is H or COCH 3 , and R 2 is phenyl or OC(CH 3 ) 3 .

2. The method according to claim 1 , wherein the purified amphiphilic block copolymer consists of a hydrophilic block (A) in an amount of 40 to 95% by weight and a hydrophobic block (B) in an amount of 5 to 60% by weight; and the hydrophobic block (B) has a number average molecular weight of 200 to 10,000 Daltons.

3. The method according to claim 1 , wherein the compound of Formula 1 is a compound of the following Formula 1a and/or a compound of the following Formula 1b:

wherein R 1 and R 2 are the same as defined in claim 1 .

4. The method according to claim 1 , wherein the compound of Formula 1 is the compound of the following Formula 1c:

5. The method according to claim 4 , wherein the compound of Formula 1c is the compound of the following Formula 1d and/or the compound of the following Formula 1e:

6. The method according to claim 1 , wherein the organic solvent is a water-miscible organic solvent.

7. The method according to claim 6 , wherein the water-miscible organic solvent is selected from the group consisting of alcohol, acetone, tetrahydrofuran, acetic acid, acetonitrile, dioxane and combinations thereof.

8. The method according to claim 1 , wherein the pharmaceutical composition does not contain ether solvent.

9. The method according to claim 1 , wherein the amphiphilic block copolymer has a number average molecular weight of 1,000 to 50,000 Daltons.

10. The method according to claim 1 , wherein the amphiphilic block copolymer comprises an A-B type diblock copolymer consisting of a hydrophilic block (A) and a hydrophobic block (B), or a B-A-B type triblock copolymer.

11. The method according to claim 1 , wherein the amphiphilic block copolymer comprises the hydrophilic block in an amount of 20 to 95% by weight, and the hydrophobic block in an amount of 5 to 80% by weight.