Liquid chromatography tandem mass spectrometry method for the quantification, pharmacokinetics and pharmacodynamics of triamcinolone acetonide and hydrocortisone in camel plasma

A sensitive, specific and rapid liquid chromatographic–tandem mass spectrometric (LC–MS/MS) method was developed and validated to quantify triamcinolone acetonide and hydrocortisone concentrations in camel plasma. Samples were prepared by solid-phase extraction using Oasis HLB cartridges. Separation was achieved with an Phenomenex Kintex C18 column (2.6 μm × 2.1 mm × 50 mm). The mobile phase was 0.1% formic acid (solvent A) and methanol with 0.1% formic acid (solvent B). A linear gradient was used at a flow rate of 0.3 ml/min with a run time of 7.5 minutes. The ionisation was optimised with positive electrospray source using multiple reaction monitoring transitions. The method was successfully applied to study the pharmacokinetic triamcinolone acetonide in camels (n = 5) following intramuscular administration of a dose of 50 µg/kg body weight. The data was analysed by non-compartmental analysis. The results obtained (median and ranges) were as follows: the terminal elimination half-life (t1 / 2) was 77.7 (42.9-120.2) h, AUC0-∞ was 747.7 + 383.4 (h*ng ml^-1), Cmax was 14.2 (11.8-26.1) ng/ml and Tmax was 3.0 (0.5-4.0) h. The plasma cortisol concentration was significantly lower than basal levels at time 1.5 h and remained significantly depressed until the last sampling day.