Simultaneous determination of unbound cefoperazone in rat blood and brain using microdialysis

A sensitive microbore HPLC method was developed for the simultaneous determ ination of unbound cefoperazone in rat blood and brain using microdialysis. Two microdialysis probes were inserted into the jugular vein/right atrium a nd brain striatum of Sprague-Dawley rats, Cefoperazone (50 mg kg(-1), i.v.) was then administered via the femoral vein. Blood and brain dialysates wer e collected and eluted with a mobile phase containing methanol-100 mM monos odium phosphoric acid (30:70, v/v, pH 5.5). The wavelength of the UV detect or was set at 254 nm. The detection limit of cefoperazone was 20 ngmL(-1) I socratic separation of cefoperazone was achieved within 10 min. The intra- and inter-assay accuracy and precision of the analyses were less than or eq ual to 10% in the range of 0.05-10 mu g mL(-1). The ratio of the area under the concentration curve of cefoperazone in rat brain and blood was estimated to be about 7.8%. It is concluded that cefope razone is capable of penetrating the blood-brain barrier.