title: A rapid HPLC method for monitoring plasma levels of caffeine and theophylline using solid phase extraction columns.
abstract: A simple HPLC method for the determination of caffeine and theophylline in plasma is described. Separation of theobromine, paraxanthine, theophylline, beta-hydroxyethyltheophylline and caffeine is obtained using a mobile phase of 1% acetic acid/methanol (83:17, v/v) and a Waters Associates NOVA-PAK C18 column protected by a Guard-PAK precolumn module containing a Guard-PAK CN cartridge. Rapid sample preparation is achieved by solid-phase extraction columns (Bond-Elut C18, 1 mL capacity) which provide excellent recovery values for both drugs. The cost per sample using this approach can be minimised by column regeneration and re-use. Results obtained for theophylline are in good agreement with values determined by other techniques.
mesh_terms: D002110:Caffeine / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005069:Evaluation Studies as Topic; D005454:Fluorescence Polarization; D006801:Humans; D007118:Immunoassay; D007124:Immunoenzyme Techniques; D011786:Quality Control; D013806:Theophylline / Q000097:blood*
chemical_list: D002110:Caffeine; D013806:Theophylline