Determination of benperidol and its reduced metabolite in human plasma by high-performance liquid chromatography and electrochemical detection.

An isocratic high-performance liquid chromatographic method with electrochemical detection for the quantification of benperidol and its suggested reduced metabolite TVX Q 5402 in human plasma is described. The method included a two-step solid-phase extraction on reversed-phase and cation-exchange material, followed by separation on a cyanopropyl silica gel column (5 microns; 250 mm x 4.6 mm I.D.). The eluent was 0.15 M acetate buffer (pH 4.7) containing 25% acetonitrile (w/w). Spiperone served as internal standard. The inclusion of the cation-exchange step provided sample purity higher than those achieved with other methods. After extraction of 1 ml of plasma, concentrations as low as 0.5 n…

Diurnal Variations of Plasma Interleukin-6 in Man: Methodological Implications of Continuous Use of Indwelling Cannulae

Pharmacokinetics and bioavailability of benperidol in schizophrenic patients after intravenous and two different kinds of oral application

Pharmacokinetics and bioavailability of benperidol were determined in 13 schizophrenic patients after acute administration of 6 mg benperidol as an intravenous (i.v.) bolus injection, orally as liquid, and orally as tablets using a partially randomized cross-over design. Drug plasma levels were determined by high performance liquid chromatography with electrochemical detection and subjected to model independent pharmacokinetic analyses. After i.v. dosing the geometric means (mean-g) were 3.2 min for the distribution half-life, 5.80 h for the elimination half-life (t1/2 beta), 4.21 l/kg for the distribution volume, 7.50 h for the mean residence time (MRT), and 0.50 l/(h*kg) for the clearance…

Determination of Homovanillic Acid in Human Plasma Using HPLC with Electrochemical Detection and Automated Solid Phase Extraction

Abstract An isocratic HPLC method with electrochemical detection for the quantification of homovanillic acid (HVA) is described. The method included automated solid phase extraction on C-18-reversed phase material, followed by separation on a 3-μm Nucleosil 100 C18 column (250 mm × 4.6 mm I. D.) with a 100 mM citric acid solution (pH 6.6) containing 4% acetonitrile (v/v) as eluent at a flow rate of 0.6 ml/min. Isovanillinic acid served as internal standard. Extractability of both analytes was ca. 80 %. After extraction of 1 ml of plasma, coefficients of variation of replicate analyses were below 10 % in the naturally occuring concentration range.

Interleukin-6 in plasma collected with an indwelling cannula reflects local, not systemic, concentrations.

Plasma levels of benperidol, prolactin, and homovanillic acid after intravenous versus two different kinds of oral application of the neuroleptic in schizophrenic patients

Plasma levels of prolactin (PRL) and the butyrophenone neuroleptic benperidol (BPD) were closely followed 0 to 48 h after acute application of 6 mg BPD as intravenous injection, orally as liquid, and orally as tablets in 12 schizophrenic patients using a partially randomized cross over design. Drug concentrations showed application specific pharmacokinetic behavior with complete elimination within 48 h. All three applications led to a biphasic PRL response with pronounced initial plasma PRL peaks returning to baseline levels within 48 h. The results suggest that after acute neuroleptic challenge BPD plasma levels as low as 2-3 ng/ml can be sufficient for complete depletion of pituitary PRL …