Specific and sensitive high-performance liquid chromatographic determination of glyburide

A specific and sensitive high-performance liquid chromatographic method has been developed for the rapid determination of intact glyburide in dog serum. With butylparaben as an internal standard, 1 ml of acid-buffered serum was extracted with toluene and an aliquot of the toluene was evaporated to dryness. The redissolved residue was chromatographed on a microparticulate reversed-phase column, and quantitation was achieved by monitoring the UV absorbance of the eluate at 228 nm. The response was linear, and the lower detection limit was approximately 20 ng/ml. Assay precision, as estimated by analyzing replicate samples of a laboratory standard, was better than 6% (CV). The utility of the analytical methodology for the determination of this highly potent sulfonylurea in pharmacokinetic studies in the dog was demonstrated.