Quantitation of tigecycline, a novel glycylcycline [corrected] by liquid chromatography.

An ion-paired HPLC assay was developed to determine tigecycline (GAR-936) concentrations in Hank's balanced salts solution, tigecycline intra-cellular concentrations in human polymorphonuclear neutrophils (PMNs) and tigecycline concentrations in human serum. Minocycline was used as internal standard, 5% trichloroacetic acid was added to lyse PMNs and also precipitate proteins in PMNs and serum. The top aqueous layer was aspirated for HPLC assay. The chromatograms were performed with a reversed-phase C18 column with UV detector. The mobile phase consisted of acetonitrile, phosphate buffer (pH 3) and 1-octanesulfonic acid at a flow rate of 1 ml/min. Good linearity and recovery were achieved over the range of standard curves. The relative standard deviations of three quality controls for intra- and inter-day precision were less than 6.4%, and the relative errors of the intra- and inter-day accuracy were less than 7.0%. Tigecycline in Hank's buffer, PMNs and serum was stable under different test conditions. This new liquid chromatography assay is a simple, accurate and reproducible method for determining tigecycline in different matrix.