Multicenter studies on the pharmacokinetic profile of sustained-release oral diltiazem (300 mg) after once a day repeated administration: influence of age.

The influence of age on the pharmacokinetics of the oral sustained release diltiazem Mono-Tildiem LP 300 mg was investigated in 12 middle-aged (40-64 years), 12 elderly (65-80 years) patients and compared to a control group of 54 young healthy volunteers (18-36 years). Each subject received daily a single dose of diltiazem slow release (300 mg) in the morning for 5 consecutive days. On the fifth day of treatment, the pharmacokinetic parameters of diltiazem and of 2 of its circulating metabolites (N-monodemethyldiltiazem and deacetyldiltiazem) were evaluated.

Stereoselective determination of unchanged and glucuroconjugated eliprodil, a new anti-ischaemic drug, in human plasma and urine by precolumn derivatization and column-switching high-performance liquid chromatography with fluorescence detection.

An HPLC method was developed and validated for the determination in human plasma and urine of the enantiomers of eliprodil, (+/-)-alpha-(4-chlorophenyl)-4[(4-fluorophenyl) methyl]piperidine-1-ethanol hydrochloride, a new anti-ischaemic agent administered as a racemate. Both enantiomers are present in human plasma in unchanged and glucuroconjugated form, whereas only the glucuroconjugated form is excreted into urine; as a consequence, such metabolites in human plasma and urine should be submitted to enzymatic deconjugation with beta-glucuronidase (Escherichia coli) before being extracted. The general method involves a liquid-liquid extraction of eliprodil and internal standard from alkalinized plasma or urine with n-hexane, evaporation of the organic phase and derivatization with (S)-(+)-naphthylethyl isocyanate to give carbamate diastereoisomeric derivatives of (S)-(+)- and (R)-(-)-eliprodil and internal standard; after evaporation of the derivatizing mixture and dissolution of the residue in a small volume of phosphate buffer-acetonitrile (60:40, v/v), an aliquot is injected into a column-switching HPLC system.

Determination of amisulpride, a new benzamide derivative, in human plasma and urine by liquid-liquid extraction or solid-phase extraction in combination with high-performance liquid chromatography and fluorescence detection. application to pharmacokinetics.

Amisulpride (SOLIAN) belongs to the benzamide series and shows antischizophrenic and antidepressant (anti-dysthymic) properties in man. Two methods suitable for pharmacokinetic investigations are proposed for the determination of amisulpride in human plasma. For the liquid-liquid extraction (LLE) based method, the plasma, added with the internal standard (an amisulpride analogue) is alkalinised with NaOH and extracted with a diethyl ether-chloroform mixture.

Stereospecific determination of amisulpride, a new benzamide derivative, in human plasma and urine by automated solid-phase extraction and liquid chromatography on a chiral column. application to pharmacokinetics.

Amisulpride, a drug belonging to the benzamide series, demonstrates antischizophrenic and antidepressant (antidysthymic) properties in man. For the pharmacokinetic studies of the racemic drug in man, a method of determination based on solid-phase extraction (SPE) from plasma and HPLC on a stereoselective column was developed. For this aim, one millilitre of plasma, after the addition of the internal standard, tiapride or metoclopramide, is diluted with a borate buffer at pH 9, then automatically loaded onto a SPE C18 100-mg column.

Determination of diltiazem and its main metabolites in human plasma by automated solid-phase extraction and high-performance liquid chromatography: a new method overcoming instability of the compounds and interference problems.

An automated sample preparation method, based on solid-phase extraction (SPE) was developed on an ASPEC-Gilson device and combined with HPLC for the determination of diltiazem and three of its metabolites in human plasma (N-desacetylmonodesmethyldiltiazem, N-monodesmethyldiltiazem, O-desacetyldiltiazem). A 1-ml volume of plasma is diluted with 0.5 ml of 0.