title: Analysis of drug contamination from parabens in theophylline olamine.
abstract: Contaminants in a commercial enema sample of theophylline olamine were found to be derived from parabens and ethanolamine. These contaminants, whose presence was characterized by the loss of preservatives and solubilizing agent, were isolated directly from the drug sample and identified. A high-performance liquid chromatographic (HPLC) system was developed to separate completely and to measure quantitatively theophylline, the two impurities, 4-hydroxybenzoic acid and N-(2-hydroxyethyl)-4-hydroxybenzamide, and the remaining parabens. The material balance obtained from the results of quantitative HPLC indicated the formation of these impurities at the expense of parabens. TLC, IR, and UV spectrophotometry and NMR and mass spectrometric analyses were used for identification or for comparisons of the new compound and the known N-(2-hydroxyethyl)benzamide.
mesh_terms: D001565:Benzoates / Q000138:chemical synthesis; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002855:Chromatography, Thin Layer / Q000379:methods; D004340:Drug Contamination / Q000032:analysis; D004983:Ethanolamines / Q000032:analysis* / Q000138:chemical synthesis; D007536:Isomerism; D010226:Parabens / Q000032:analysis*; D013806:Theophylline / Q000032:analysis*
chemical_list: D001565:Benzoates; D004983:Ethanolamines; D010226:Parabens; C031059:theophylline olamine; D013806:Theophylline