DETERMINATION OF DEXAMETHASONE SODIUM PHOSPHATE AND DEXAMETHASONE BASE IN ONE SAMPLE OF HORSE PLASMA OR/AND SYNOVIAL FLUID USING HIGH RESOLUTION LIQUID CHROMATOGRAPHY. TECHNICAL NOTE Determinación de la dexametazona fosfato sódica y la dexametazona base en una muestra de plasma o líquido sinovial de equino utilizando la cromatografia líquida de alta resolución. Nota técnica

This trial describes a simple and fast procedure for the determination and quantification of dexamethasone sodium phosphate (DSP) and dexamethasone base (DB) using one small sample of horse synovial fluid. The objective was to use High Resolution Liquid Chromatography (HPLC) for the determination of DSP and DB in synovial fluid. For this purpose, a HPLC method was developed by using standard curves using known concentrations of DSP and DB. The method was further tested using synovial fluid and blood plasma from horses treated with dexamethasone. With the results obtained it was observed that the linearity of the method had a correlation coefficient of 0.990. The minimum detection limit (LD) for synovial fluid was 0.350 µg/mL. The minimum quantification limit (LC) was computed with the formula LC = LD volume of Injection/Volume of Sample, 0.35 µg/mL* 25 µL/1000 mL = 1.4 µL. In conclusion the described method is adequate for the determination of DSP and DB in one sample of horse plasma and/or synovial fluid. The method probed to be reliable and adequate for the determination of DSP and its DB in blood and synovial fluid of horses treated with the anti inflammatory drug.