Biomedical subjects

I Quintens

Publications and source records attributed to I Quintens.

3 recordsLinked to original sources

PubMed1997

Bioavailability of different artemisinin tablet formulations in rabbit plasma--correlation with results obtained by an in vitro dissolution method.

The demonstration of a good overall correlation with in vivo data is the ultimate proof of qualification for any dissolution-rate test. For artemisinin, a very hydrophobic compound at a high content in oral solid dosage forms, all official dissolution apparatus were estimated unsuitable. A modified two phase partition-dissolution method was applied to solve this problem. This study reports on the bioavalability of three different formulations of artemisinin tablets in rabbit plasma. Artemisinin concentrations in plasma were determined by liquid chromatography. A linear correlation between results obtained by the partition-dissolution method described and the obtained in vivo data confirmed the validity of the dissolution method.

Animals↗

PubMed1994

Quantitative analysis of quaternary ammonium antiseptics using thin-layer densitometry.

A thin-layer chromatography method for quantitative analysis of quaternary ammonium antiseptics is described. Silanized silica gel was used as the stationary phase. The mobile phase consisted of methanol-25% (m/v) sodium acetate solution-acetone (65:35:20). The method is able to separate the chain homologues of benzalkonium chloride, cetylpyridinium chloride and cetrimide. Detection was performed using a colour reaction with potassium triiodide solution. The different homologues were quantified using UV densitometry at 400 nm. A number of commercial samples was analysed using this method. From the results it appears that it is worthwhile to have a limit test for the composition of quaternary ammonium antiseptics in pharmacopoeial monographs, the more so as the antibacterial activity depends on it.

Acetates↗

PubMed1993

Quantitative analysis of tylosin by column liquid chromatography.

A column liquid chromatographic method suitable for the quality control of tylosin A is described. The determination can be carried out on different C8 or C18 columns, using a mobile phase containing acetonitrile, 0.2 M tetrabutylammonium hydrogensulphate, 0.2 M phosphoric acid and water. The flow-rate is 1 ml/min and detection is performed at 280 nm. The method shows good selectivity towards the major components tylosin A, B, C and D and demycinosyltylosin. Minor degradation products, mainly observed in solutions, are also separated. The compositions of several standards are compared and results for a number of commercial samples are presented.

Calibration↗