MODIFIED LIQUID-CHROMATOGRAPHIC ASSAY FOR DILTIAZEM AND METABOLITES IN HUMAN PLASMA

Diltiazem (DTZ) is an anti-hypertensive and anti-anginal agent which i s also used clinically as a metabolic inhibitor to reduce cyclosporin- A metabolism The present communication describes an HPLC/UV method for measuring DTZ and 3 of its major metabolites. This method has a LOQ b elow 2.5 mu g/L and within run CV's ranging from 11.3 to 1.9% at conce ntrations of 2.5 and 100 mu g/L, and between-run CV's ranging from 10. 5 to 4.9% at concentrations of 75 and 350 mu g/L, respectively. The me thod has been applied successfully to 11 renal transplant recipients t aking a variety of other drugs.