Mass fragmentographic analysis of clomipramine and its mono-demethylated metabolite in human plasma.

A mass fragmentographic method for the quantification of clomipramine (CIM) and monodemethyl-clomipramine (DCIM) in human plasma was developed. The deuterium labelled analogues of the compounds were used as internal standards. The sensitivity of the method allows the determination of CIM and DCIM in plasma after oral doses with a standard deviation less than 7% at concentrations of 25 ng/ml. The method was applied to the analysis of drug concentrations in plasma of clomipramine treated healthy volunteers and depressed patients. After acute treatment the level of DCIM in plasma was low as compared to chronical treatment.