Nuclear magnetic resonance spectroscopic determination of dicyclomine hydrochloride in tablet, capsule, and injection dosage forms

Abstract

A rapid and specific nuclear magnetic resonance (NMR) spectroscopic method was developed for determining dicyclomine hydrochloride in tablet, capsule, and injection dosage forms. The method consists of an extraction step with chloroform, evaporation of the solvent, addition of maleic acid as an internal standard, dissolution of the mixture in deuterated chloroform-deuterated acetone (40 + 60), NMR spectral determination, and integration of the peaks of interest. The concentration of dicyclomine hydrochloride in the dosage form was calculated from the integral values for the peaks of the test compound and the internal standard. The average recovery value +/- the standard deviation (n = 5) of dicyclomine hydrochloride added to synthetic samples was 99.7 +/- 0.9% (coefficient of variation 0.9%). The assay values for various commercial tablets, capsules, and injectables analyzed by using the proposed method differed in all cases by less than 1% from those obtained by using the USP XX titrimetric method. There was no interference from stearate, an excipient found in tablets and capsules, or from chloral hydrate, a preservative found in injectables .