Details for Patent: 6,849,628

Title:	Optically active compounds
Abstract:	The present invention relates to the preparation of substantially pure diastereoisomers of derivatives of tetrahydrofolate and the use of such diastereoisomers. More particularly the present invention provides a process for the preparation of a desired substantially pure (6R or 6S) diastereoisomer of a derivative of tetrahydrofolic acid or salt or ester. The process comprises the steps of: attaching a chiral auxiliary group at either N-5 or N-10 of a mixture of 6R and 6S diastereoisomers of tetrahydrofolic acid, separating the new diastereoisomers, recovering the desired new diastereoisomer (6R or 6S) corresponding to the desired (6R or 6S) diastereoisomer, and converting the substantially pure new diastereoisomer recovered into the corresponding diastereoisomer.
Inventor(s):	Wood; Hamish Christopher Swan (Glasgow, GB), Suckling; Colin James (Glasgow, GB), Rees; Lilias Gilmour (Glasgow, GB)
Assignee:	The University of Strathclyde (Glasgow, GB)
Filing Date:	Aug 27, 2002
Application Number:	10/228,820
Claims:	1. A pharmaceutical composition for therapeutic use which consists essentially of a therapeutically effective amount, sufficient for the treatment in conjunction with 5-fluorouracil of human beings for colorectal cancer, of a pharmaceutically acceptable compound which is a (6S) diastereoisomer selected from the group consisting of (6S) leucovorin (5-formyl-(6S)-tetrahydrofolic acid) and pharmaceutically acceptable salts and esters of (6S) leucovorin; wherein the compound consists of a mixture of (6S) and (6R) diastereoisomers and consists of at least 92% by weight of the (6S) diastereoisomer, the balance of said compound consisting of the (6R) diastereoisomer; in combination with a pharmaceutically acceptable carrier; and in conjunction with a therapeutically effective amount of 5-fluorouracil. 2. The pharmaceutical composition according to claim 1 which consists essentially of about 92% by weight of the (6S) diastereoisomer. 3. The pharmaceutical composition according to claim 1 which consists essentially of 92% to 95% by weight of the (6S) diastereoisomer. 4. The pharmaceutical composition according to claim 1 which consists of greater than 95% by weight of the (6S) diastereoisomer. 5. The pharmaceutical composition according to claim 1 which consists essentially of 200 to 2000 mg of the mixture of (6S) and (6R) diastereoisomers. 6. The pharmaceutical composition according to claim 1 wherein the 5-fluorouracil is present in a therapeutically effective amount of 200 to 2000 mg. 7. The pharmaceutical composition according to claim 1 wherein the mixture of (6S) and (6R) diastereoisomers is present in the composition in an amount of at least about 10 grams. 8. The pharmaceutical composition according to claim 1 the form of divided doses. 9. The pharmaceutical composition according to claim 1 wherein said composition is present in a form selected from the group consisting of injectable solutions, powders for injection which can be reconstituted shortly before use by addition of water for injection, and tablets. 10. The pharmaceutical composition according to claim 1 wherein the mixture of (6S) and (6R) diastereoisomers is produced as a result of separation by differential solubility in a polar solvent of a (6S) diastereoisomer from an initial mixture containing equal amounts of (6S) and (6R) diastereoisomers.