Simultaneous HPLC determination of nitrendipine and impurities of the process of synthesis

A method has been developed for separation of nitrendipine and its impurities of reaction partners and side reaction products by high-performance liquid chromatographic method on a RP-18 column and detection at 238 nm. The mobile phase composition that provided an acceptable nitrendipine resolution, in large excess and possible impurities, in a short elution time, is methanol:water (70:30) and pH 3. Linearity (r> or =0.999), reproducibility (RSD=0.8--1.4%), determination limit (0.5--2%) and recovery (99.8--102.3) were validated and found to be satisfactory. This method enables monitoring of the process of synthesis, as well as the choice of the synthetic design.