Objective: The present work aims to develop and validate stability indicating a novel liquid chromatography method with applicability i.e. to study the pharmacokinetics factor as well as estimate Tamoxifen (TMX) in bio-analytes, using Ultra High Pressure Liquid Chromatography/ Mass Spectrometry (UPLC-ESI-Q-TOF-MS/MS) in plasma. Methods: A bioanalytical method based on UPLC-ESI-Q-TOF-MS/MS has been developed and validated for the quantitative determination of TMX in female mice plasma using Clomiphine as an Internal Standard (IS). After Liquid-liquid extraction (LLE), analyte and IS, chromatographic separation was achieved on ACQUITY UPLC BEH C18 Waters column with dimensions; 100 mm × 2.1 mm; 1.7 μm, isocratic mobile phase (Acetonitrile:2 mM ammonium formate: 90:10; v/v), and a flow rate of 0.25 mL min-1. Results: The transitions occurred at m/z 372.1→178.1 and m/z 407.1 → 100.1 for TMX and IS, respectively. Liquidliquid extraction technique (LLE) using ethyl acetate was applied in order to optimize the recovery of analytes in mice plasma. The run and retention time of TMX were 6.0 and 2.63 minutes, respectively while the linear dynamic range established was 1.002-4001.07 ng/ml (r2>0.998 ± 0.0003). Intra-assay and inter-assay accuracy (% RSD) was found in the range; 2.43- 3.49. Conclusion: The proposed LC–MS/MS assay method is simple, rapid and sensitive for the determination of TMX in mice plasma for pharmacokinetic studies. Analytes were stable under various conditions i.e. autosampler, freeze–thaw, at room temperature, and under deep freeze conditions.
Key words Tamoxifen, Breast Cancer, UPLC/ESI-Q-TOF-MS/MS method Validation, Polymeric nanoparticles, Pharmacokinetics.