Preparation, identification, and quantitative NMR determination of silyl derivatives of 6-aminopenicillanic acid, 7-amino-3-methyl-delta3-cephem-4-carboxylic acid, and 7-amino-3-acetoxymethyl-delta3-cephem-4-carboxylic acid.

A rapid and accurate method for the quantitative determination of the extent and ratio of amino and carboxyl group trimethylsilylation of 6-aminopenicillanic acid, 7-amino-3-methyl-delta3-cephem-4-carboxylic acid, and 7-amino-3-acetoxymethyl-delta3-cephem-4-carboxylic acid is presented. The method utilizes NMR spectroscopy and is based on the difference in chemical shifts between N-trimethylsilyl and O-trimethylsilyl groups or, in cephalosporin derivatives, between the methyl group in the 3-position and free amino resonances. The spectra of the N,O-bis(trimethylsilyl) derivatives are discussed.

High-performance liquid chromatographic determination of cephacetrile.

A rapid and accurate quantitative determination of cephacetrile in finished bulk and dosage forms is reported. The high-performance liquid chromatographic method is free of interference by acetyl hydrolysis products and synthesis by-products. The assay can be performed in about 15 min, affording less than 0.7% coefficients of variation within and between days. The chromatographic results are in good agreement with the microbiological assay requested by the "Code of Federal Regulations" for certification of cephacetrile sodium.