A Rapid High Performance Liquid Chromatographic Procedure for the Analysis of Cloxacillin and/or Nafcillin in Serum: PDF OnlyA Rapid High Performance Liquid Chromatographic Procedure for the Analysis of Cloxacillin and/or Nafcillin in SerumSoldin, Steven J.; Tesoro, Angel M.; MacLeod, Stuart M.Author Information Departments of Clinical Biochemistry and Pharmacology, University of Toronto, and Departments of Biochemistry and Pharmacology, Hospital for Sick Children, Toronto, Canada Address correspondence and reprint requests to Dr. Soldin at the Department of Biochemistry, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8. Therapeutic Drug Monitoring: Volume 2 - Issue 4 - p 417-422 Buy Abstract Summary: A rapid, reliable procedure for the analysis of cloxacillin and/or nafcillin in 100 μl of serum or plasma is described. Percentage analytical recovery of cloxacillin, nafcillin, and internal standard (5-(p-hydroxyphenyl)-5-phenylhydantoin) were 95, 91, and 85%, respectively. The between-day precision of the method at cloxacillin concentrations of 2, 8, and 20 mg/liter was 14.7, 11.6, and 10.3%, respectively. At identical serum concentrations, the values obtained for nafcillin were 15.3, 12.4, and 12.2%, respectively. The method will be used to study the pharmacokinetics of both drugs in patients with cystic fibrosis who are on long-term therapy. Preliminary data providing the i.v. half-life, clearance, and volume of distribution are presented for two normal individuals. © Lippincott-Raven Publishers.