title: Determination of trimethoprim in biological fluids by high-performance liquid chromatography.
abstract: A rapid, sensitive, and specific high-performance liquid chromatographic assay was developed for the determination of trimethoprim in blood, plasma, and urine using normalphase (adsorption) chromatography on a microparticulate silica column and UV monitoring at 280 nm. Trimethoprim is selectively extracted from the biological sample matrix at alkaline pH with chloroform, providng nearly quantitative extraction (greater than 95%) and a sensitivity limit of 0.01 to 0.02 microgram/ml blood or plasma, without interference from sulfonamides.
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004338:Drug Combinations; D006801:Humans; D013420:Sulfamethoxazole / Q000494:pharmacology; D014295:Trimethoprim / Q000097:blood* / Q000494:pharmacology / Q000652:urine
chemical_list: D004338:Drug Combinations; D014295:Trimethoprim; D013420:Sulfamethoxazole