Quantitative determination of imipramine and desipramine in human blood plasma by direct densitometry of thin-layer chromatograms

Imipramine and desipramine have been estimated in the plasma of patients receiving therapeutic doses of imipramine. The compounds were extracted as bases into n-heptane, separated by thin-layer chromatography and transferred into coloured spots by an oxidative procedure. The quantification was made with a new densitometric technique of high sensitivity. The coefficient of variation was 11–16% at concentrations of 20 μg litre−1 (71ṁ2 nmol and 75ṁ0 nmol litre−1 for imipramine and desipramine respectively) and the recovery was 70–81%.