Study on transport of sophocarpine in millicell system by LC-MS

Objective: To establish LC-MS method for determination of sophocarpine (SC) and investigate its transport in millicell system. Method: Separation of SC was carried out by an extend-C₁₈ column (2.1 mm x 50 mm, 5 μm, agilent technologies, USA). The mobile phase was acetonitrile-water containing 10 mmol·L^-1 ammonium acetate (15:85) at the flow rate of 0.2 mL· min^-1. The ESI ion source was set in the positive ion polarity mode for acquiring all mass spectrometry data. The selective ion monitoring (SIM) was used, and protonated molecules [M + H]⁺ were detected at m/z 247.3 for SC. This LC-MS method was applied to determine SC concentration in millicell system. Result: The linearity of SC ranged from 5 to 2 000 μg·L^-1 (r = 0.998 5). The quantification limit of SC was 5 μg·L^-1. SC transport in Caco-2 cells was time and concentration dependent, and SC transport complied with the passive diffusion. Its average apparent permeability coefficient (P_app) is 3.159 × 10^-5 cm·s^-1. Conclusion: This assay was highly sensitive and specific enough for determining concentrations of SC in millicell system, and SC showed good transport in millicell system.