Quantitative analysis of Codeine phosphate in preparations using 31 P-NMR Techniques

Abstract

Codeine phosphate was an active ingredient in various antitussive preparations. The assay methods of Codeine phosphate in preparations have been performed by extraction and titration with sulfuric acid or High Performance Liquid Chromatography or Gas Chromatography. The development of Nuclear Magnetic Resonance technique which has been used to study the phosphate in red blood cell, was used to assay codeine phosphate in various preparations. Effect of various conditions, pH, viscosity and concentration were studied. Quantitative analysis of codeine phosphate by ³¹P-NMR technique showed a reliable percent label amount comparable to the official method of U.S.P.