Determination of 2,6-dimethyl-4-(2'-nitrosophenyl)-3,5-pyridinedicarboxylic acid dimethylester in nifedipine by derivative UV-spectrophotometry in bulk material and pharmaceutical forms.

A method for the determination of 2,6-dimethyl-4-(2'-nitrosophenyl)-3,5-pyridinedicarboxylic acid dimethylester in nifedipine (bulk material and pharmaceutical formulations) by second-derivative ultraviolet spectrophotometry is described. The procedure is simple and rapid and gives accurate and precise results.