Analysis of diltiazem and desacetyldiltiazem in serum by high-performance liquid chromatography.

This paper describes a simple high-performance liquid chromatographic (HPLC) method for the determination of diltiazem and desacetyldiltiazem in human serum. After basic methyl-tert-butyl ether extraction and back-extraction with hydrochloric acid, the drug and its metabolite was injected into a Supelcosil LC-CN column and the absorbance of the eluate was measured at 240 nm. The sensitivity was 5 ng/ml and the obtained precision, selectivity and stability during storage were adequate for the performed clinical studies in patients therapeutically treated with diltiazem.