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Y A Beltagy

Publications and source records attributed to Y A Beltagy.

17 recordsLinked to original sources
PubMed1992

A rapid first-derivative spectrophotometric analysis of cephalexin and cephradine in human urine.

A rapid, simple, and accurate first-derivative spectrophotometric method has been established for the determination of either cephalexin or cephradine in urine. Quantitative analysis of each antibiotic was achieved by measuring the peak amplitude at 268 nm. The relative and absolute recoveries ranged from 98.90 to 104.00% for cephalexin and from 97.85 to 105.10% for cephradine. The within-day coefficient of variation varied from 3.27 to 6.45%. The applicability of the method for the determination of the cumulative amount of either cephalexin or cephradine excreted unchanged in urine, following an oral dose containing 500 mg of the drug to a human male volunteer, is demonstrated.

Adult↗
PubMed1981

Oxidative degradation of 6-selenoguanosine in aqueous solutions.

The degradation of 6-selenoguanosine (NSC 137679) (I) in water and in various buffer systems was investigated. Drug degradation in aqueous media was monitored by high-pressure of I in various chromatography. Some kinetic aspects of the degradation of I in various buffer systems at 25 degrees also were studied spectrophotometrically. The degradation, which requires oxygen, involves autoxidation of I to the corresponding diselenide, which produces a selenide and metallic selenium in the presence of oxygen. This degradation pathway differs from that reported fro the oxidation of related thio compounds.

Chemistry, Pharmaceutical↗
PubMed1980

Antioxidants in purification, stabilization, and formulation of the antineoplastic agent 6-selenoguanosine.

6-Selenoguanosine (NSC 137679) was stablized and formulated as a lyophilized parenteral paroduct using ascorbic acid as an antioxidant. In addition to preventing the oxidation of 6-selenoguanosine to the corresponding diselenide in aqueous solution, ascorbic acid reduced the diselenide already in the bulk drug. Dithioerythritol and sodium bisulfite also were evaluated as antioxidants. Dithioerythritol had effects similar to ascorbic acid, while sodium bisulfite reacted rapidly with 6-selenoguanosine.

Antineoplastic Agents↗