Determination of morphine, codeine, thebaine, papaverine and noscapine in rat plasma by UPLC-MS/MS

In this work, a UPLC-MS/MS assay was established for the determination of morphine, codeine, thebaine, papaverine and noscapine in rat plasma. ACQUITY UPLC BEH C18 column was employed for chromatographic separation with the mobile phase comprised acetonitrile-10 mmol L−1 ammonium acetate aqueous solution (0.05% aqueous ammonia) using gradient elution. Midazolam was used as internal standard (IS). Electrospray ionization (ESI) in positive-ion mode with reaction monitoring (MRM) was used for quantitative analysis. The calibration curves for morphine, codeine, thebaine, papaverine and noscapine demonstrated good linearity (r > 0.995) in the range of 5–500 ng mL−1 for morphine and codeine, and 1–100 ng mL−1 for thebaine, papaverine and noscapine. The intra-day and inter-day precisions of morphine, codeine, thebaine, papaverine and noscapine were within 15%, the intra-day and inter-day accuracies were 89–114%, the recovery was better than 65%, and the matrix effects were 96–112%. The developed UPLC-MS/MS assay was successfully applied in the pharmacokinetics of papaverine and noscapine.