METHOD FOR DETERMINING IMPURITY A IN DOSAGE FORMS OF GABAPENTIN Russian patent published in 2022 - IPC G01N24/08 A61K31/197 

FIELD: pharmaceuticals.

SUBSTANCE: group of inventions relates to medicine and pharmaceuticals and can be used for controlling the quality of substances or various dosage forms of gabapentin by identifying impurity A therein followed by quantification. Method for determining impurity A in substances of gabapentin by nuclear magnetic resonance spectroscopy on protons (¹H NMR), wherein impurity A constitutes 2-azaspiro[4,5]decane-3-one, is characterised by dissolving the substance of gabapentin in deuterated water (D₂O) and dimethyl sulphoxide (DMSO) while intensely shaking until complete dissolution, identifying the characteristic signals of gabapentin and impurity A thereof by recording the ¹H spectrum on an NMR spectrometer with a proton working frequency no less than 400 MHz at a temperature of 300 K, calibrating the chemical shift scales of 1H for a signal of the DMSO methyl group δ= 2.71wt. pts., and calculating the weight fraction of impurity A relative to gabapentin using the measured integral signal intensities. The group of inventions also relates to a variant of the method for determining impurity A in medicinal products of gabapentin in the form of capsules and to an application of said methods for determining impurity A in a substance of gabapentin or dosage forms thereof.

EFFECT: increase in the accuracy of determining impurity A without utilising standard samples or building a calibration function.

6 cl, 6 dwg, 1 tbl, 4 ex