Claims for Patent: 6,441,168

Summary for Patent: 6,441,168

Title:	Stable crystalline salts of 5-methyltetrahydrofolic acid
Abstract:	This invention relates to stable crystalline salts of 5-methyl-(6R,S)-, -(6S)- and -(6R)-tetrahydrofolic acid, to methods of producing these salts and to the use thereof use as a constituent for the production of drugs or as a food additive, and to preparations containing these salts.
Inventor(s):	Muller; Rudolf (Schaffhausen, CH), Moser; Rudolf (Schaffhausen, CH), Egger; Thomas (Effretikon, CH)
Assignee:	Eprova AG (Schaffhausen, CH)
Application Number:	09/551,405
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 6,441,168
Patent Claims:	1. A crystalline salt of 5-methyl-(6R,S)-, -(6S)- or -(6R)-tetrahydrofolic acid said crystalline salt having a water of crystallization of at least one equivalent per equivalent of 5-methyltetrahydrofolic acid. 2. A crystalline salt according to claim 1, of 5-methyl-(6S)- or -(6R)-tetrahydrofolic acid. 3. A crystalline calcium salt according to claim 1, of 5-methyl-(6S)- and -(6R)-tetrahydrofolic acid having .gtoreq.3 equivalents of water. 4. A crystalline calcium salt of 5-methyl-(6S)-tetrahydrofolic acid with 2 theta values of 6.5, 13.3, 16.8 and 20.1 (Type I) said crystalline salt having a water of crystallization of at least one equivalent per equivalent of 5-methyltetrahydrofolic acid. 5. A crystalline calcium salt according to claim 1, of 5-methyl-(6S)-tetrahydrofolic acid with 2 theta values of 5.3, 6.9, 18.7 and 21.1 (Type II). 6. A crystalline calcium salt according to claim 1, of 5-methyl-(6S)-tetrahydrofolic acid with 2 theta values of 6.8, 10.2, 15.4 and 22.5 (Type III). 7. A crystalline calcium salt according to claim 1, of 5-methyl-(6S)-tetrahydrofolic acid with 2 theta values of 6.6, 15.9, 20.2 and 22.5(Type IV). 8. A method of producing crystalline salts of 5-methyl-(6R,S)-, -(6S)- and 5-methyl-(6R)-tetrahydrofolic acid, comprising subjecting a salt of 5-methyl-(6R,S)-, -(6S)- or -(6R)-tetrahydrofolic acid in a polar medium to a thermal treatment, at a temperature above 60.degree. C., and thereafter crystallizing said salt from the resultant heated solution. 9. A method according to claim 8, wherein the crystallisation is effected after thermal treatment at a temperature above 85.degree. C. 10. A method according to claim 8, wherein the crystallisation is effected from a solution. 11. A method according to claim 8, wherein the crystallisation is effected from a suspension. 12. A method according to claim 10, characterised in that crystallisation is effected from water or from a mixture of water and an organic solvent which is miscible with water. 13. A method according to claim 8, wherein said salt is an alkaline earth salt. 14. A method according to claim 8, wherein said salt is calcium. 15. A method of producing 5-methyl-(6S)-tetrahydrofolic acids with 2 theta values of 5.3, 6.9, 18.7 and 21.1 (Type II) comprising drying sufficiently 5-methyl-(6S)-tetrahydrofolic acid with 2 theta values of 6.5, 13.3, 16.8 and 20.1 (Type I). 16. A method of producing 5-methyl-(6S)-tetrahydrofolic acid with 2 theta values of 6.8, 10.2, 15.4 and 22.5 (Type III) comprising subjecting to sufficient thermal treatment at above 90.degree. C., a crystalline calcium salt of 5-methyl-(6S)-tetrahydrofolic acid with 2 theta values of 6.5, 13.3, 16.8 and 20.1 (Type I). 17. A method of producing 5-methyl-(6S)-tetrahydrofolic acid with 2 theta values of 6.6, 15.9, 20.2, 22.5 (Type IV) comprising subjecting to sufficient thermal treatment at above 95 .degree. C., a crystalline calcium salt of 5-methyl-(6S)-tetrahydrofolic acid with 2 theta values of 6.5, 13.3, 16.8 and 20.1 (Type I).