Determination of clomipramine and desmethylclomipramine in plasma by means of liquid chromatography.

A method is presented for the determination of clomipramine and its major metabolite desmethylclomipramine in plasma. After extraction with n-hexane, the components are separated by high performance liquid-solid chromatography on silica gel and detected with a UV detector. The detection limits are 2 ng/ml for clomipramine and 10 ng/ml for desmethylclomipramine. Recoveries from plasma exceed 95% for both drugs. In routine analysis, 30-40 samples can be handled in one day. The practical use of the method is shown in plasma concentration-time curves after oral and intramuscular administration of clomipramine.