DETERMINATION OF FAMOTIDINE IN HUMAN PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH COLUMN-SWITCHING

A rapid, sensitive and robust reverse-phase high performance liquid ch romatographic (HPLC) method with column switching and an internal stan dard for the quantitative determination of famotidine in human plasma is described. Famotidine and the internal standard were isolated from plasma samples by cation exchange solid phase extraction with SCX cart ridges. The chromatographic separation was accomplished by an Inertsil C4 column with a mobile phase of acetonitlile/phosphate aqueous solut ion, connected by a switching valve to a BDS Hypersil C8 column with a mobile phase of acetonitrile/sodium dodecyl sulfate and phosphate aqu eous solution. UV detection was set at 267 nm. The standard curve was linear in the concentration range of 1-100 ng ml(-1). The intraday coe fficients of variation at all concentration levels were less than 10%. The interday consistency was assessed by running QC samples during ea ch daily run. The limit of quantification for famotidine in human plas ma was 1 ng ml(-1). The method has been utilized to support clinical p harmacokinetic studies in healthy volunteers who received famotidine 1 0 mg orally. (C) 1998 Elsevier Science B.V. All rights reserved.