Back to results
US 5,670,655 AGranted
Method for analyzing isomers of enalapril and enalaprilat
AssigneeMerck & Co., Inc.
InventorsXue-Zhi Qin, Giuseppina Visentini, Qingxi Wang
Life of this patent
Estimating the term…
Abstract
The invention relates to a method for analyzing degenerates of enalapril maleate and enalaprilat, potent angiotensin converting enzyme inhibitors.
Claims4
A method for analyzing the degradates of enalapril comprising:
- (a) stressing a composition containing enalapfil;
- (b) chromatographing the stressed composition of enalapril;
- (c) comparing the chromatogram of stressed enalapril with all known enalapril degradates;
- (d) analyzing the stressed composition by liquid chromatography-mass spectrometry to detect a molecular ion and fragmentation pattern for the unknown degradates;
- (e) reacting a sample of enalaprilat with t-butyl lithium to form a mixture of diastereomers of enalaprilat;
- (f) chromatographing the diastereomers of enalaprilat;
- (g) comparing the chromatogram of stressed enalapril with the chromatogram for the mixture of diastereomers of enalaprilat;
- (h) identifying the unknown enalapril degradate as a diastereomer of enalapril;
- (i) synthesizing standards of enalaprilat SRS and SSR diastereomers;
- (j) chromatographing the SRS and SSR diastereomers of enalapril;
- and
- (k) comparing the chromatograms of the SRS and SSR diastereomers with the chromatogram of the stressed enalapril to identify which diastereomer of enalaprilat corresponds with the unknown degradate.
9 more elements
Dependencies are inferred from the claim text.