Objective: To develop a RP-HPLC method for determination of cinnamic acid in rat plasma.
Method: The plasma samples were acidified with acetic acid and extracted with chloroform. Cinnamic acid was separated on a Kromasil C18 column (250 mm x 4.6 mm, 5 microm) eluted with a mobile phase of methanol-acetonitrile-water-glacial acetic acid (25:20:55:0.3) at a flow rate of 1.0 mL x min(-1) and room temperature with UV detection at 278 nm, carbamazepine as internal standard.
Result: The standard curve was linear over the range of 4.0 to approximately 400 ng x mL (-1) r = 0..99 9. The LOQ was 4.0 ng x mL(-1), the mean extraction recovery of the spiked samples at low, middle and high levels was 86.4%, while the mean method recovery was 100.3%. The RSD of intra-day and inter-day were both less than 6.0%.
Conclusion: The method was sensitive, specific, accurate and precise, which was used to study the pharmacokinetic profile of cinnamic acid in rat plasma after oral administration of the Subing orally disintegrating tablets.