Development and Validation of an HPLC Method for the Determination of p-methoxycinnamic Acid in Rabbit Plasma

p-methoxycinnamic acid (pMCA) is an active compound obtained from the hydrolysis of ethyl p- methoxycinnamate acid (EpMC). It is isolated from Kaempferia galanga Linn with anti-inflammatory and analgesic effects. A simple, rapid, accurate and selective high performance liquid chromatography method was developed to determine the p-methoxycinnamic acid consentrations in rabbit plasma using a C18 reversed-phase analytical column. Ethanol was used for protein precipitation to prepare plasma samples, with chromatographic separation performed using a µ-Bondapak C18 (3.9 mm x 300 mm i.d). The mobile phase consists of methanol and water (30:70), with a flow rate 0.8 mL/min, maximum pressure of 300 bars and UV detection of 286 nm. The proposed method was validated by performing selectivity, linearity, accuracy, precision, LOD and LOQ for pMCA with no interfering peaks. Its overall analytical run time was 10 min, which is useful for in vivo studies of p-methoxycinnamic acid.