Pyrolysis gas chromatographic-mass spectrometric study of medicinal sulphonamides

Simple methods for the qualitative identification and quantitative determination of macrolide antibiotics

Pyrolysis-gas chromatography is shown to be a rapid straightforward method for the qualitative differentiation of the macrolide antibiotics erythromycin, oleandomycin, troleandomycin, spiramycin and tylosin. Organic salts do not interfere and identification of erythromycin and troleandomycin in commercial products is viable. Spectrophotometric quantitation of these same five antibiotics after reaction with concentrated sulphuric acid is studied at about 470 nm. Reaction conditions such as acid concentration, time and temperature are provided. The sugar moieties of the antibiotics are proposed as the reactive sites. Detection limits are about 0.2-1.0 microg ml-1 [corrected] and analysis of pharmaceutical products should be possible.

Determination of trimethoprim, sulphamethoxazole and its N4-acetyl metabolite in biological fluids by high-performance liquid chromatography

A normal-phase high-performance liquid chromatographic method was developed to determine therapeutic concentrations of trimethoprim, sulphamethoxazole, and its N4-acetyl derivative in biological fluids. The compounds are extracted at pH 6.2 using ethyl acetate--chloroform in a single extraction. The detection limit is 15 ng/ml for trimethoprim, 20 ng/ml for sulphamethoxazole, and 10 ng/ml for its N4-acetyl metabolite. The method is rapid, sensitive, precise, and well suited to clinical pharmacokinetic investigations.

The identification of ibuprofen and analogues in urine by pyrolysis gas chromatography mass spectrometry

The pyrolysis gas chromatography mass spectrometry of Ibuprofen, Fenoprofen, Naproxen and Ketoprofen, a series of anti-inflammatory propionic acid derivatives, is shown to proceed via decarboxylation and elimination to yield characteristic ethyl and vinyl fragments. The pyrogram enables the identification of the drug to be achieved as the pure compound, in a formulated dosage form or excreted in urine. The presence of metabolites derived from Ibuprofen causes four new fragments to be observed in the urine pyrogram. The identification of 16 components of the control urine pyrogram is presented.

Determination of trimethoprim and sulfamethoxazole (co-trimoxazole) in body fluids of man by means of high-performance liquid chromatography

A high-performance liquid chromatographic method for the determination of trimethoprim, sulfamethoxazole and its metabolite and a series of structurally related sulfonamides is described. The half-life time of elimination of sulfamethoxazole and its metabolite N4-acetylsulfamethoxazole is 9 h for both compounds. The renal excretion rate of sulfamethoxazole depends strongly on the urinary pH. The renal excretion rate of the metabolite N4-acetylsulfamethoxazole is not dependent on the urinary pH.