A new HPLC/UV method for the determination of clindamycin in dog blood serum

A new HPLC method for the quantitative determination of clindamycin in dog blood serum at levels down to 80 ng/ml has been developed. Samples were deproteinised with acetonitrile and clindamycin was extracted with dichloromethane. Chromatographic analysis was carried out on a C(18) reversed-phase analytical column in the presence of tetra-n-butylammonium hydrogen sulfate (TBA), as an ion-pairing agent. UV detector wavelength was set at 195 nm. The assay was validated for a concentration range from 80 to 6000 ng/ml serum. Good linearity was observed in the entire concentration range. The limit of quantification (LOQ) was 80 ng/ml and the limit of detection (LOD) was 60 ng/ml. Regression of accuracy data yielded an overall mean recovery value (+/-S.E.M.) of 93.98+/-0.42%, while precision data revealed coefficient of variation (CV (%)) values lower than 4.41%. The method was successfully applied to determine drug concentrations in serum samples from dogs that had been orally administered clindamycin hydrochloride.