Development and Validation of UHPLC/ESI-Q-TOF-MS Method for Terbutaline Estimations in Experimental Rodents: Stability Effects and Plasma Pharmacokinetics

An ultra high performance liquid chromatography-electrospray ionization-tandem mass spectrometric method (UHPLC/ESI-Q-TOF-MS) for the analysis of terbutaline (TB) in Wistar rat plasma has been developed and validated. The chromatographic separation was achieved on a Waters ACQUITY UPLCTM BEH C18 (100.0 mmx2.1 mm; 1.7 μm) column using isocratic mobile phase, consisting of 2 mM ammonium acetate and acetonitrile (90: 10; v/v), at a flow rate of 0.25 mL min-1. The transitions occurred at m/z 226.19→152.12 for TB, and m/z 260.34→183.11 for the internal standard. The recovery of the analytes from Wistar rat plasma was optimized using liquid- liquid extraction technique (LLE) in ethyl acetate. The total run time was 3.0 min and the elution of TB occurred at 1.85±0.05 min. The linear dynamic range was established over the concentration range 1–1000 ng mL-1 (r2; 0.9938±0.0005) for TB. The intra-assay and inter-assay accuracy in terms of % CV was in between 1.8–3.5. The lower limit of quantitation (LLOQ) for TB was 1.0 ng mL-1. Analytes were stable under various conditions (in autosampler, during freeze–thaw, at room temperature, and under deepfreeze conditions). The developed method was successfully applied for pharmacokinetic profiling in rodents.