Validation of HPLC-UV assay of caffeic acid in emulsions

An accurate, sensitive, precise and rapid reversed-phase high-performance liquid chromatographic method was successfully developed and validated for the determination of caffeic acid (CA) in emulsions. The best separation was achieved on a 250 × 4.6 mm, 5.0 µm particle size RP18 XDB Waters column using ethanol and purified water (40:60 v/v) adjusted to pH 2.5 with acetic acid as the mobile phase at a flow rate of 0.7 mL/min. Ultraviolet detection was performed at 325 nm at ambient column temperature (25°C). The method was linear over the concentration range of 10-60 µg/mL (r(2) = 0.9999) with limits of detection and quantification of 1.44 and 4.38 µg/mL, respectively. CA was subjected to oxidation, acid, base and neutral degradation, as well as photolysis and heat as stress conditions. There were no interfering peaks at or near the retention time of CA. The method was applied to the determination of CA in standard and pharmaceutical products with excellent recoveries. The method is applicable in the quality control of CA.