QUANTITATIVE PROTON MAGNETIC-RESONANCE ANALYSIS OF KETOPROFEN IN CAPSULES

A rapid and specific proton magnetic resonance (PMR) spectroscopic met hod was developed for determining ketoprofen in capsules. Mandelic aci d was used as the internal standard and DMSO-d(6) served as the PMR so lvent. Undeuterated DMSO was also used as a solvent and good results w ere obtained since the resonance signals of ketoprofen and mandelic ac id used in the analysis did not interfere with the signal and side ban ds of DMSO. The concentration of drug per unit dose was calculated fro m the integral values for the resonance signals of ketoprofen at 1.40 ppm and mandelic acid at 5.10 ppm. The average recovery value for keto profen in synthetic samples was 100.16 +/- 0.03% (SD) with a coefficie nt variation of 0.03%. The method using commercial products gave compa rable results to those obtained by the method of BP 1993.