Determination of Ciprofloxacin (Bay o 9867) in Biological Fluids by High-Performance Liquid Chromatography

Abstract

A high-performance liquid chromatographic method for the analyses of ciprofloxacin (BAY o 9867) (1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinoline carboxylic acid hydrochloride) in human serum, plasma and urine samples is described. Diluted serum, plasma, and urine samples are injected onto a RP-18 column without prior extraction or clean-up procedure. Ciprofloxacin is separated from the ballast by an eluent consisting of an 0.025M H₃PO₄ solution adjusted to pH=3 with tetrabutylammonium hydroxide and acetonitrile. Ciprofloxacin is detected fluorimetrically giving a detection limit of 8ng/ml in plasma and serum and of 50ng/ml in urine. A statistical evaluation of the assay showed acceptable accuracy and precision for 10 to 500ng of BAY o 9867 per ml in serum and plasma and for 50ng to 600ng of BAY o 9867 per ml of diluted urine specimens. This method was used to monitor the concentrations of BAY o 9867 in serum, plasma and urine of volunteers after oral administration of ciprofloxacin.