Determination of total alkaloids in plasma of rats after oral administration with Mahuang Decoction by acid dye colorimetry / 中草药

ABSTRACT

Objective: To propose the feasibility of the vortex method of acid dye colorimetry replacing extraction method to determine the content of total alkaloids in plasma of rats after oral administration with Mahuang Decoction. Methods: The contents of total alkaloids in plasma of rats orally administered with Mahuang Decoction extracted by traditional extraction method and vortex method were determined by acid dye colorimetry, and the results were contrasted and analyzed. Results: The extraction method and vortex method had good linear relationship in the range of 4-40 and 4-80 μg/mL with the average recovery rates of 95.63% (RSD = 1.92%) and 111.55% (RSD = 0.26%), respectively. The regression equations established were A = 0.0171 C + 0.2355, r = 0.9855 and A = 0.0068 C + 0.0102, r = 0.9964. The metabolic processes of total alkaloids in rats were both complied with the one-compartment model. The main pharmacokinetic parameters AUC, Cmax, tmax, and t1/2 were 5.30 × 105 min·μg/mL, 57.13 μg/mL, 37.20 min, 6403.78 min and 1.94 × 106 min·μg/mL, 663.20 μg/mL, 361.90 min, 1756.87 min. The Cmax and AUC of vortex method were 11.61 times and 3.66 times compared with those of extraction method. Conclusion: The vortex method is more rapid, accurate, sensitive, simple, stable, safe, and reproducible and has little harm to laboratory assistants, which can extract the total alkaloids in maximum, with the necessity, scientificity, and practicality of replacing traditional extraction method.