Quantitative proton magnetic resonance spectroscopic determination of nifedipine and its photodecomposition products from pharmaceutical preparations.

A rapid (5 min), accurate, and precise (SD 0.51%) analytical method involving 1H NMR spectroscopy for determination of nifedipine and its photodecomposition products in pharmaceutical preparations is described. Analysis of commercial samples by 1H NMR and USP NF XVII procedures has indicated a maximum difference of 1.0%. The 1H NMR method is recommended for analysis of nifedipine since it provides sufficiently accurate results, together with a unique spectrum as a confirmatory identification of nifedipine, its photodecomposition products, and other impurities.