On-line solid-phase extraction of ceftazidime in serum and determination by high-performance liquid chromatography.

A column-switching high-performance liquid chromatographic assay is described for the determination of ceftazidime (a third-generation cephalosporin) in human serum. The method does not require prior sample pretreatment. Serum is directly injected in a first chromatographic column for sample clean-up and extraction. Thereafter, using an on-line column-switching system, the drug is quantitatively transferred and separated on a second, analytical column followed by determination using ultraviolet absorption at 258 nm. The technique allows direct, rapid, precise, and simple determination of ceftazidime in serum over the range of 1-250 micrograms/ml using 12.5 microliters of serum. This method was applied to study the pharmacokinetics of the drug in patients undergoing vascular surgery.