Ion-Paired Liquid Chromatographic Determination of Cefazolin in Canine Serum and Tissues

Abstract

Abstract Cefazolin is commonly used as a prophylactic antibiotic in dogs undergoing total hip arthroplasty. A sensitive high-performance liquid chromatographic method was developed for the determination of cefazolin in canine serum and tissues. The tissues were those in contact with the hip prothesis; namely, the coxofemoral joint capsule, cancellous bone from the acetabulum and bone marrow from the femoral canal. The method involved filtration of diluted serum or tissue extracted with ethanol:acetonitrile:water (40:10:50) through a 30,000 molecular weight cut-off filter. Separation of cefazolin from other components was by ion-paired (dodecanosulfonate) high performance liquid chromatography using a reversed-phase column eluted with acetonitrile/water solution. The ultraviolet absorbance of the column effluent was monitored at 230 nm. Recovery of cefazolin spiked at 10 μg/ml from serum was 89.8% with a coefficient of variation (CV) of 5.3% (n=10). Recovery of cefazolin spiked at 5 μg/ml from tissue extracts of joint capsule, cancellous bone and bone marrow was: 93.9%, 98.2%, and 104.2% respectively, with a CV of 6.7%, 10.2% and 10.6% respectively (n=10). A correlation coefficient of 0.9999 occurred with cefazolin in aqueous solution (n=5). The limit of detection for cefazolin was approximately 10 ng/ml of serum or tissue extract.