PubMed Health⌕ Search

Biomedical subjects

D C Tsilifonis

Publications and source records attributed to D C Tsilifonis.

8 recordsLinked to original sources
PubMed1980

High-pressure liquid chromatographic assay of quinestrol tablets.

A specific assay for quinestrol was developed using high-pressure liquid chromatography. The estrogen was separated from tablet excipients on a chemically bonded hydrocarbon column utilizing acetonitrile-water as the mobile phase. Linearity studies were carried out using peak height measurements, and the detector response to the concentration of the steroid was confirmed. This procedure was rapid, accurate precise, and specific for the assay of the synthetic estrogen in the presence of formulation excipients and structurally similar estrogens.

Chromatography, High Pressure Liquid↗
PubMed1977

Selective photometric determination of betamethasone benzoate and other 21-hydroxycorticosteroids.

Condensation of the glyoxal obtained by cupric acetate oxidation of 21-hydroxycorticosteroids with acetous phenylhydrazine reagent affords a near UV chromophore. All of the tested corticosteroids, including triamicinolone acetonide, which gives low color yields in the Porter-Silber reaction and its Lewbart-Mattox modification, gave similar absorption maxima (362-370 nm) and molar absorptivities (epsilon = 17,000-20,500). Since corticosteroid 21-esters and oxidation products do not undergo the reaction, the assay method based on it is stability indicating for betamethasone benzoate and the other test compounds. Procedures are described for the assay of two topical betamethasone benzoate preparations and hydrocortisone and prednisolone tablets; recovery and precision data are given.

Betamethasone↗