A validated HPTLC method for determination of terbutaline sulfate in biological samples: Application to pharmacokinetic study

Abstract Terbutaline sulfate (TBS) was assayed in biological samples by validated HPTLC method. Densitometric analysis of TBS was carried out at 366 nm on precoated TLC aluminum plates with silica gel 60F254 as a stationary phase and chloroform–methanol (9.0:1.0, v/v) as a mobile phase. TBS was well resolved at RF 0.34 ± 0.02. In all matrices, the calibration curve appeared linear (r^2 P 0.9943) in the tested range of 100–1000 ng spot^-1 with a limit of quantifica-tion of 18.35 ng spot ^-1. Drug recovery from biological fluids averaged P95.92%. In both matrices, rapid degradation of drug favored and the T0.5 of drug ranged from 9.92 to 12.41 h at 4 °C and from 6.31 to 9.13 h at 20 °C. Frozen at 20 °C, this drug was stable for at least 2 months (without losses 10%). The maximum plasma concentration (Cpmax) was found to be 5875.03 ± 114 ng mL ^-1 , which is significantly higher than the maximum saliva concentration (Csmax, 1501.69 ± 96 ng mL ^-1). Therefore, the validated method could be used to carry out pharmacoki- netic studies of the TBS from novel drug delivery systems.