RESUMO
Object To study the pharmacokinetics of cinnamic acid in BAOXIN PILL * in rat. Methods Plasma concentration of cinnamic acid was determined by HPLC under the following conditions: column: Hypersil ODS C 18 (150 mm?4.6 mm, 5 ?m); column temperature 30 ℃; mobile phase methanol-1% acetic acid (45∶55); flow rate 0.5 mL/min; detection wavelength 273 nm; aliquot injected 10 ?L. Results A method for the determination of plasma cinnamic acid concentration by HPLC was established. Regression equation of cinnamic acid peak area (Y) and plasma concentration (X) was found to be: Y= 4 973.534 8 +42 867.96 678 X; correlation factor r=0.999 8; rate of cinnamic acid recovery from plasma=97.50% and RSD=1.33%; detection limit=0.15 ng; minimal dectable concentration in rat plasma=75 ng/mL. Absorption pattern of cinnamic acid after ig does showed linearity, corresponding to a first order absorption and elimination of open chamber model. The t 1/2 (K a)=7.12 min; t max =53.29 min, C max =0.20 ?g/mL, and t 1/2 (Ke)=340.74 min. Conclusion The pharmacokinetic parameters obtained in this study may be attributed to the combined action of cinnamic acid and other constituents in the compound preparation of BAOXIN PILL.