Quantification of triamcinolone acetonide in ocular tissues after intravitreal injection to rabbit using liquid chromatography-tandem mass spectrometry.

A sensitive and selective liquid chromatographic-tandem mass spectrometric method was developed for quantification of triamcinolone acetonide (TA) in rabbit ocular tissues. After a simple liquid-liquid extraction using tert-butyl methyl ether, TA and internal standard methylprednisolone were separated on a C₁₈ column with a mobile phase of acetonitrile:water:formic acid (60:40:0.1, v/v/v) and quantified by the use of selected reaction monitoring mode with a total run time of 4 min. The method was validated in tissue homogenates with a daily working range of 1-1000 ng/mL with correlation coefficient of more than 0.99 and a sensitivity of 1 ng/mL as lower limit of quantification, respectively. The mean intra-day and inter-day precisions were less than 10% and accuracy values were higher than 90%. This method was fully validated for the accuracy, precision and stability studies. The method proved to be accurate and specific, and was applied to an in vivo biodistribution study of TA after intravitreal injection to rabbits. Values of mean residence time in vitreous humor, crystalline lens and aqueous humor were 27.7, 35.8 and 20.0 days, respectively.