Showing papers by "Juan A. Squella published in 1982"
TL;DR: 2-Hydroxy-3-phenyl-6-methylpyrazine is identified as the product obtained by acidic degradation of cephalexin in the presence of formaldehyde and gives a well-defined reduction wave with a half-wave potential in 5M hydrochloric acid.
19 citations
01 Jan 1982
TL;DR: On etudie la reduction polarographique de l’2-hydroxi-3-phenyl-6-methylpyrazine dans un acide dilue as mentioned in this paper.
Abstract: Le 2-hydroxi-3-phenyl-6-methylpyrazine est un produit de degradation acide de l’ampicilline.On etudie la reduction polarographique de l’2-hydroxi-3-phenyl-6-methylpyrazine dans un acide dilue.Dans un milieu fortement acide, la reduction se produit par une onde irreversible a deux electrons, trois protons qui correspondent a la reduction du groupe — C = N —.La reaction se fait au moyen d’une diffusion controlee avec un coefficient de temperature de 1.83 °C —1 et une energie d’activation de 3.51 kcal mol —1 .
2 citations
TL;DR: Hydrolysis of cloxacillin at pH 4.0 yields an electroactive product which can be determined by polarography, and individual capsule and composite assays as well as interference tests are described.
Abstract: Hydrolysis of cloxacillin at pH 4.0 yields an electroactive product which can be determined by polarography. Depending on the concentration of cloxacillin, one of 2 peaks was obtained: The potential ac peaks for a 4.36 mM cloxacillin solution were peak I, -0.23 V and peak II, -0.13 V. For analytical purposes, the first peak was used. A linear relationship was established for levels of cloxacillin between 2.2 X 10(-5) and 2.2 X 10(-3)M. Average recovery was 98.8% (SD 1.8), indicating satisfactory accuracy for the method. Individual capsule and composite assays as well as interference tests are described.
1 citations