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Biomedical subjects

P De Backer

Publications and source records attributed to P De Backer.

42 records · Page 3Linked to original sources

Pharmacokinetics and bioavailability of erythromycin in pigeons (Columba livia).

Tissue and plasma concentrations were determined after intravenous and oral administration of erythromycin to pigeons to establish the pharmacokinetics and bioavailability of the drug. A short mean half-life of elimination of 0.9 h was found. The relative bioavailability after direct crop administration of erythromycin thiocyanate or erythromycin ethylsuccinate at a dosage rate of 100 mg/kg was less than 10%. At a drug concentration in drinking water of 1 g/l, erythromycin plasma levels were barely detectable, whilst lung and trachea concentrations reached a maximum of 1.6 micrograms/ml. Even after crop administration of 100-mg/kg erythromycin thiocyanate, low plasma levels were obtained, whilst lung and trachea concentrations were substantially higher. Prescribed drinking-water regimens seemed unable to yield therapeutic tissue concentrations. Only individual crop administration seemed an appropriate medication method. The use of erythromycin ethylsuccinate did not present any advantage in comparison with erythromycin thiocyanate.

Administration, Oral↗

Pharmacokinetics and bioavailability of ronidazole from a prolonged release tablet in the homing pigeon (Columba livia).

The pharmacokinetics of ronidazole and the bioavailability of a prolonged release tablet were studied in the homing pigeon. After intravenous administration of 5 mg ronidazole, the drug plasma concentration profile fitted a one-compartment open model. The mean half-life of the drug was 11 h and the volume of distribution was 0.86 l/kg. Total body clearance was 0.056 l/h/kg. A sustained release matrix tablet exhibited prolonged drug release in vitro. After oral administration of the matrix tablet to pigeons drug absorption was nearly complete. When given on an empty stomach, the tablet failed as a prolonged release system. Administration to previously fed pigeons resulted in an increase in tmax and a decrease in Cpmax.

Administration, Oral↗

Pharmacokinetics of sulfamerazine and antipyrine in neonatal and young lambs.

The disposition of sulfamerazine after oral and after IV administrations was studied in lambs at different times after birth. There was a gradual increase in systemic clearance and plasma binding until the 9th week. After sulfamerazine was given orally, there was a marked evolution in the shape of the concentration-time curves in function of age, strongly suggesting a defective absorption rate in the first weeks after birth. For antipyrine, too, the clearance increased gradually during the period of study, but absorption seemed to be rapid in the very young animals.

Administration, Oral↗

Selected ion monitoring assay for bromhexine in biological fluids.

A method has been developed for quantification of bromhexine in plasma using gas chromatography mass spectrometry with selected ion monitoring. A deuterium labelled analogue was synthesized and used as the internal standard. To evaluate the gas chromatographic electron capture detection method described earlier, 23 plasma samples have been analysed by both techniques. Although a good correlation was shown, selected ion monitoring was superior to the electron capture detection method for levels below 3 ng ml-1. The mass spectrometric method has also been used to set up a pharmacokinetic study of bromhexine in horses. Urine extracts were subjected to gas chromatographic mass spectrometric analysis to identify the different metabolites of bromhexine. Three groups of metabolites were detected and identified.

Animals↗