Liquid chromatography-mass spectrometry method for the determination of thiamphenicol in rabbit tears.

A simple and sensitive liquid chromatography-mass spectrometry (LC-MS) method was described for the determination of thiamphenicol in rabbit tears. Chromatographic separation of the analyte was achieved on a C18 column using a mobile phase of acetonitrile and 10 mmol/l ammonium acetate solution (60:40, v/v). Selected ion monitoring (SIM) in negative mode was used for analyte quantification at m/z 354.4 for thiamphenicol and at m/z 137.1 for salylic acid. The run time was less than 6 min. Linearity over the concentration range of 0.032-32.0 ng/ml for thiamphenicol was obtained and the lower limit of quantification was 0.032 ng/ml. For each level of QC samples, inter- and intra-day precisions (R.S.D.) were <or=5.2% and 8.3%, respectively, and the accuracy (RE) was +/-2.8%. The present LC-MS method was successfully applied to the pharmacokinetic studies of thiamphenicol in situ forming gel in rabbit tears.