RESUMO
An improved HPLC method for the measurement of cimetidine and its major metabolite-cimetidine sulfoxide-is described. The mobile phase was a mixture of methanol-ammonium phosphate (20:80), and methanol was used to elute the drug avoiding the use of acetonitrile, a very hazardous solvent. A device has been developed to wash simultaneously ten or more cartridges and to reduce the time of analysis. With this procedure a plasma sample could be analyzed in less than 30 min. The limit of detection was 0.125 micrograms/ml for cimetidine and 1.00 micrograms/ml for cimetidine sulfoxide. The absolute recovery for cimetidine was 83% and 40% for its major metabolite; is greater than that reported by previous studies. The proposed method is rapid, accurate and precise, and it should be useful for clinical, bioavailability and pharmacokinetic studies of cimetidine.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cimetidina/sangue , Cromatografia Líquida de Alta Pressão/instrumentação , Cimetidina/análogos & derivados , Cimetidina/farmacocinética , Humanos , Metanol , SolventesAssuntos
Antipirina/antagonistas & inibidores , Cimetidina/administração & dosagem , Guanidinas/administração & dosagem , Fígado/metabolismo , Adolescente , Antipirina/análise , Antipirina/metabolismo , Criança , Cromatografia Líquida de Alta Pressão , Cimetidina/sangue , Cimetidina/metabolismo , Humanos , Saliva/análiseRESUMO
Ten patients (6 to 27 years of age) who had severe pancreatic exocrine insufficiency due to cystic fibrosis were studied to determine whether cimetidine would improve dietary fat and nitrogen absorption. When a constant diet was consumed and oral pancreatic enzymes were administered, the addition of cimetidine (150 or 200 mg taken orally one-half hour before meals) signficantly reduced fecal fat excretion from 25.3 +/- 2.9 to 17.3 +/- 2.1 gm/24 hours and fecal nitrogen excretion from 4.5 +/- 0.6 to 3.4 +/- 0.5 gm/24 hours (P less than 0.05). Lower doses of cimetidine resulted in less significant reductions of steatorrhea and azotorrhea. Cimetidine may be a useful adjunct to oral pancreatic enzyme therapy in patients with cystic fibrosis who continue to have steatorrhea and azotorrhea with enzyme therapy alone.