METHOD OF OBTAINING ANTIEMETIC MEDICATION Russian patent published in 2012 - IPC C07D209/88 C07D209/84 A61K31/403 A61P1/08 

FIELD: medicine, pharmaceutics.

SUBSTANCE: claimed invention relates to method of obtaining optically pure antiemetic medication, R-(+)-ondansetron, which includes the following stages: a) processing of ondansetron hydrochloride with base, which is selected from group, containing metal hydroxide and carbonate or bicarbonate; b) processing of free ondansetron base with R/S-(+)-n-toluyl tartrate acid in mixture of dimethylforamide and water obtaining salt of 3-R/S-ondansetron-n-toluene tartrate acid; c) fractional recrystallisation of salt of 3-R/S- ondansetron-n-di-toluene tartrate acid from mixture of dimethylformamide and water, if necessary, in presence of primer obtaining salt of 3-R-(+)- ondansetron-n-di-toluene tartrate acid of required enantiomer purity; and processing by base with obtaining free base of 3-R-(+)- ondansetron, and at first ondansetron salt is dissolved in water at room temperatute, after which dimethylformamide is added to solution, with further heating of mixture to 80-85°C, cooling to 60°C and filtration at that temperature, ratio of water and dimethylformamide volume in mixture constituting 2:1; d) processing of free base of R-(+)-ondansetron with hydrochloric acid in presence of alcohol as solvent obtaining 3-R-(+)-ondansetron hydrochloride.

EFFECT: claimed method is less time-consuming and ensures higher product purity in comparison with known methods-analogues.

4 cl, 9 ex