Serum concentrations of paliperidone versus risperidone and clinical effects.

Purpose: The major aim of this multicenter retrospective analysis was to examine the relationship between paliperidone serum concentrations and clinical effects in patients treated with this new antipsychotic drug. Intra-individual variability in trough serum concentrations was also analyzed in patients under treatment with either the paliperidone-extended release (ER) formulation or the risperidone immediate-release formulation.

Methods: Data were obtained from 217 patients of four medical centers who were being followed by therapeutic drug monitoring (TDM).

Determination of citalopram and escitalopram together with their active main metabolites desmethyl(es-)citalopram in human serum by column-switching high performance liquid chromatography (HPLC) and spectrophotometric detection.

We established a method for automated quantitative analysis of (es-)citalopram and desmethyl(es-)citalopram in serum using column-switching high performance liquid chromatography (HPLC). For sample clean-up serum was injected onto a LiChrospher CN 20 microm precolumn using 8% acetonitrile in deionized water. Drugs were eluted by back-flush flow onto the analytical column (LiChrospher CN 5 microm) at a flow rate of 1.