title: Determination of cimetidine in human plasma by high-performance liquid chromatography following liquid-liquid extraction.
abstract: A new method is described for the determination of cimetidine in human plasma. The drug and internal standard (ranitidine) were separated on a Nucleosil C18 5 microns (25 x 4.6 mm I.D.) column using a mobile phase of acetonitrile-phosphate buffer, pH 6.2 (25:75, v/v) containing 2.5 g/l heptane sulphonic acid. The mobile phase was delivered at a flow-rate of 0.9 ml/min, detection was by ultraviolet absorption at 228 nm and concentrations were calculated on the basis of peak areas. The drugs were extracted from alkaline plasma into ethyl acetate using a salting out procedure which involved the addition of 100 ml of a saturated solution of K2CO3 to each 250-microliters plasma aliquot. The method was validated over the concentration ranges 50-3000 ng/ml and 100-7000 ng/ml for two separate studies. Mean coefficients of variation were less than 6% for both intra- and inter-assay in both studies and recoveries varied between 71 and 81%. The method was successfully applied to the determination of cimetidine in plasma for a pharmacokinetic study.
authors.affiliation: Department of Chemistry, Royal College of Surgeons in Ireland, Dublin.
authors.forename: M T
authors.initials: MT
authors.lastname: Kelly
authors.forename: D
authors.initials: D
authors.lastname: McGuirk
authors.forename: F J
authors.initials: FJ
authors.lastname: Bloomfield
mesh_terms: D000293:Adolescent; D000328:Adult; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002927:Cimetidine / Q000097:blood* / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002927:Cimetidine