title: The simultaneous determination of theophylline, theobromine and caffeine in plasma by high performance liquid chromatography.
abstract: A high performance liquid chromatographic procedure for the stimultaneous micro-scale determination of theophylline, theobromine and caffeine in plasma is described. After a single dichloromethane extraction of 0.5--0.2 ml of acidified plasma, the evaporated residue is chromatographed on a reverse-phase gC-18) column. With a mobile phase of acetate buffer (pH 4)--acetonitrile (88:12) at a flow-rate of 2.0 ml/min., the three methylxanthines are separated within six minutes. Detection at xanthines are separated within six minutes. Detection at 276-280 nm enables quantitation of 0.1 mg/1 of drug in a 0.1 ml sample. The method is reproducible, correlates well with EMIT for plasma theophylline, and is applicable to the routine monitoring of both paediatric and adult patients as well as to metabolic studies.
mesh_terms: D000328:Adult; D002110:Caffeine / Q000097:blood*; D002648:Child; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D013805:Theobromine / Q000097:blood*; D013806:Theophylline / Q000097:blood*
chemical_list: D002110:Caffeine; D013806:Theophylline; D013805:Theobromine