Automated determination of amisulpride by liquid chromatography with column switching and spectrophotometric detection

A fully automated chromatographic method including on-line blood serum or plasma clean-up, isocratic high-performance liquid chromatography (HPLC) and spectrophotometric detection was developed for quantitative analysis of the new antipsychotic drug amisulpride. After injection of serum or plasma onto the HPLC system and clean-up on a pre-column (10x4.0 mm I.D.) filled with Silica CN 20 micrometer (pore size 10 nm) by an eluent consisting of 8% acetonitrile in deionized water, the chromatographic separation was performed on Lichrospher CN (5 micrometer; 250x4.6 mm I.D.) by an eluent consisting of 50% acetonitrile and 50% aqueous potassium phosphate buffer (0.008 M, pH 6.4). The UV detector was set at 254 nm. The limit of quantification was about 10 microgram/l. The method revealed linearity between 10 and 600 microgram/l (correlation coefficients R(2)>0.9996). The inter-assay reproducibility (coefficient of variation) of quality control samples was between 2.8 and 11.3%. Inaccuracy was between -0.6 and +9.1%. The performance of daily calibration standards revealed an imprecision always below 15% and maximum inaccuracy of 7.7%. The method can be applied to therapeutic drug monitoring as well as pharmacokinetic studies of amisulpride.     

Automated determination of clomipramine and its major metabolites in human and rat serum by high-performance liquid chromatography with on-line column-switching

A fully automated method including column-switching and isocratic high-performance liquid chromatography (HPLC) was developed for simultaneous determination of the tricyclic antidepressant clomipramine and its metabolites demethylclomipramine, 2-, 8-, and 10-hydroxyclomipramine, 2-, and 8-hydroxydemethylclomipramine and didemethylclomipramine in serum. After serum injection into the HPLC system and on-line sample clean-up on a clean-up column (Hypersil CN; 10×4.6 mm) by an eluent consisting of 35% acetonitrile and 65% deionized water, the chromatographic separation was performed on an analytical column (LiChrospher CN; 250×4.6 mm I.D.) by an eluent consisting of 38% acetonitrile and 62% aqueous sodium perchlorate (0.02 M, pH 2.5). The UV detector was set at 260 nm. The limit of quantification was about 15 ng/ml for all analytes. The coefficients of variation ranged between 3 and 12% with recovery rates between 64 and 110%. Linear regression analyses revealed coefficients of correlation between 0.98 and 0.99. The method could be applied to therapeutic drug monitoring as well as metabolism studies in man and rat.     

Automated analysis of quetiapine and other antipsychotic drugs in human blood by high performance-liquid chromatography with column-switching and spectrophotometric detection

An automated HPLC method with column switching is described for the determination of quetiapine, clozapine, perazine, olanzapine and metabolites in blood serum. After clean-up on silica C8 material (20 microm particle size) drugs were separated on ODS Hypersil C18 material (5 microm; column size 250 mm x 4.6 mm i.d.) within 25 min and quantified by ultraviolet (UV) detection at 254 nm. The limit of quantification ranged between 10 and 50 ng/ml. At therapeutic concentrations of the drugs, the inter-assay reproducibility was below 10%. Analyses of drug concentrations in serum of 75-295 patients treated with therapeutic doses of the antipsychotic drugs revealed mean+/-S.D. steady state concentrations of 139+/-136 ng/ml for quetiapine, 328+/-195 ng/ml for clozapine, 48+/-27 ng/ml for olanzapine and 71+/-52 ng/ml for perazine. The method was thus suitable for routine therapeutic drug monitoring and may be extended to other drugs.