High-performance liquid chromatography with mass spectrometry detection for quantitating COL-3, a chemically modified tetracycline, in human plasma

COL-3, 6-deoxy-6-demethyl-4-dedimethylamino-tetracycline, is a matrix metal loproteinase inhibitor. A specific and sensitive analytical method was nece ssary to quantitate the analyte in human plasma. High-performance liquid ch romatography with atmospheric pressure chemical ionization mass spectrometr y detection was utilized to quantitate COL-3 from 30 to 10000 ng/ml in two calibration curves: 30-1500 and 400-10000 ng/ml. The sample preparation con sisted of acetonitrile precipitation for all plasma samples. COL-3 is separ ated on a Waters Symmetry(R) C-18 (2.1 x 150 mm) column with oxalic acid (0 .01 M, pH 2.2)-acetonitrile mobile phase. The total run time was 23 min. Id entification of COL-3 and the internal standard was through positive chemic al ionization and selective ion monitoring. A quantifying and qualifying io n for COL-3 is used to verify the presence of COL-3 in patient samples Inte r- and intra-run mean percent errors for all of the quality controls were l ess than 18.3% and relative standard deviations were all less than 14.9%. R ecovery of COL-3 and the internal standard was approximately 55 and 72%, re spectively. Freeze-thaw stability of COL-3 was variable. This method is sui table for quantifying COL-3 in patient samples and to further characterize the clinical pharmacology of this compound. (C) 2000 Elsevier Science B.V. All rights reserved.