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Biomedical subjects

G Schwartzman

Publications and source records attributed to G Schwartzman.

9 recordsLinked to original sources
PubMed1978

Ambiguities in IR and X-ray characterization of amphotericin B.

Two distinct IR spectra of amphotericin B have been reported. These differences can be obtained from the same sample by surprisingly small changes in the method of sample preparation. Type I spectra (hand-ground samples) are characterized by a sharp C = O stretching band at 1692 cm-1, and Type II spectra (vibrator-ground samples) are characterized by a broad C = O stretching band near 1710 cm-1. X-ray powder diffraction demonstrates that vibrator grinding promotes a transition from a crystalline to an amorphous phase. The two phases are not bioequivalent. Differential thermal analysis reveals a transition near 157 degrees and samples heated to 158 degrees give only Type II IR spectra. However, a marked color change accompanies such heating (i.e., structural changes affecting the chromophore have been thermally induced), while X-ray spectra show an increase of only about 30% in amorphous content. Furthermore, hand-ground samples heated to 120 degrees still display only Type I IR spectra. Thus, the vibrator-induced transition is not solely a static thermal effect. Many observed spectral lines can be assigned to specific functional groups.

Amphotericin B↗
PubMed1976

Infrared identification of maleic acid in pharmaceutical maleate salts.

Difficulties are encountered in the USP melting point identification test for maleic acid extracted from chlorpheniramine maleate. A general procedure is described for the isolation and infrared identification of the maleic acid moiety of pharmaceutical salts from drug substances or dosage forms. This procedure permits the concurrent infrared identification of the amine moiety.

Amines↗
PubMed1976

Infrared spectrophotometric analysis of medicinal gases for trace impurities.

The feasibility of examining medical gases for trace impurities, using an infrared spectrophotometer in conjunction with a 10 m gas cell, was investigated. Many of the impurities for which the USP includes limits were detected and measured at concentrations at or below those permitted by the USP; these include sulfur dioxide, carbon dioxide, carbon monoxide, and water. However, others (hydrogen sulfide, nitric oxide, and nitrogen dioxide) were not detected at these levels by this technique. Methane was found at low levels in some samples.

Carbon Dioxide↗
PubMed1975

The analysis of pharmaceuticals by combined gas chromatography-mass spectrometry. I. The analysis of a medicated aerosol spray.

A medicated aerosol product was qualitatively analyzed by combined gas chromatography-mass spectrometry. The data were processed by a minicomputer. Ten of the 11 peaks in the gas chromatogram were identified with the assistance of the National Institutes of Health/Division of Computer Research and Technology/Chemical Information System mass spectral search system. The unidentified peak is probably a member of the terpene class. The aerosol propellants were also partially analyzed by infrared spectrophotometry.

Aerosol Propellants↗