Biomedical subjects

D B Faber

Publications and source records attributed to D B Faber.

3 recordsLinked to original sources

PubMed1986

On the modulating effects of temperature, albumin, pH and calcium on the free fractions of phenobarbitone and phenytoin.

The effects of temperature, albumin, pH and Ca2+ on the binding of phenobarbitone and phenytoin to human serum albumin in buffer have been investigated using equilibrium dialysis. The free fractions of both anticonvulsants were much increased by raising the temperature. Lower free fractions were observed by increasing the albumin concentration from 5-8 g litre-1 and by raising pH from 6 to 9. No significant effect on the free fractions was observed by changing (at pH 7.4) the Ca2+ concentration from 0 to 5 mM. The observed differences in free fractions at 37 degrees C, as determined in phosphate, borate and Krebs-Ringer buffer at pH 7.4, indicate that great care is needed in the choice of dialysis fluid for dialysis of clinical samples.

Calcium↗

PubMed1977

Quantitation with high-performance thin-layer chromatography and programmed multiple development with high-performance micro-thin-layer material for drug analyses in biological fluids.

The programmed multiple development thin-layer chromatography (PMD-TLC) technique was compared with the conventional chromatographic technique on both normal and HPTLC plates. The potency of this high-performance TLC is illustrated and discussed by means of the data obtained with the determination of digitoxin in human serum. Improvement of the efficiency of TLC, resulting in a better resolution and sensitivity with PMD-TLC using using HPTLC plates, makes this high-performance TLC technique comparable to high-performance liquid chromatography. This TLC approach might lead to a sensitive, rapid, selective and simply assay for routine serial analyses and, because of its specificity and flexibility, it may facilitate drug interaction studies.

Chromatography, High Pressure Liquid↗

PubMed1977

Quantitative gas chromatographic analysis of flunitrazepam in human serum with electron-capture detection.

A rapid method for the determination of flunitrazepam and desmethylfflunitrazepam in human serum in the range 10-300 ng/ml is described. Both drugs are isolated from biological material by means of a single extraction, part of the organic phase is evaporated to dryness and the residue is dissolved in a small volume of benzene. Without further purification, the substance is determined gas chromatographically with an electron-capture detector configuration of 63Ni-type. The method permits the quantitative determination of at least 25-300 ng/ml with an overall recovery of flunitrazepam of 99.7 +/- 4.9% and of desmethylflunitrazepam of 98.6 +/- 7.8% from serum. All calculations were carried out by a data system that was programmed for this purpose. The limit of detection for flunitrazepam is of the order of 1 ng/ml in serum. The method is sufficiently sensitive and specific for therapy control purposes. The time needed for an analysis is less than 1 h.

Anti-Anxiety Agents↗