Measurement Of Doxycycline Plasma Concentrations By Calibration Curve Method With Aid Of Hplc-Esi-Ms/Ms

Abstract

The validated protein precipitation method was applied for the estimation of Doxycycline in human plasma with Doxycycline-d₃ as an internal standard by using HPLC-ESI-MS/MS. The chromatographic separation was achieved with Methanol: Acetonitrile(pH: 6.5 Adjusted with diluted ammonia solution) (20:80%, v/v) using the Discovery^® C18 HPLC Column, 2 cm × 2.1 mm, 5 μm. The total analysis time was 3.0 min and the flow rate was set to 0.7 ml/min. The mass transitions of Doxycycline and Doxycycline-d3  obtained were m/z 445.20 ®428.10 and 895.11®428.23.  Using the linear regression model, the standard curve shows a correlation coefficient (r2) greater than 0.9983 with a range of 6.00-768.00 pg/ml.