Development and validation of an LC method for simultaneous determination of ascorbic acid and three phenolic acids in sustained release tablets at single wavelength

A simple, rapid and sensitive column liquid chromatographic method was developed and validated to measure simultaneously the amount of ascorbic acid and phenolic acids at single wavelength (240 nm) in order to assess drug release profiles and drug-excipients compatibility studies for a new sustained release tablet formulation and its subsequent stability studies. A combined isocratic and linear gradient reversed-phase LC method was carried out at 240 nm. Quantification was achieved with reference to the external standards. The linearity for concentrations between 0.042 and 0.150 mg mL(-1) for ascorbic acid, 0.084-0.250 mg mL(-1) for chlorogenic acid, 0.053-0.360 mg mL(-1) for caffeic acid, and 0.016-0.250 mg mL(-1) for ferulic acid (r > 0.99 for all analytes) were established. The recovery of the active ingredients from the samples was at the range of 92.3-102.9%. Intra- and inter-day precisions were less than 2.5%. The limits of detection and quantification were 8 and 24 mu g mL(-1) for ascorbic acid, 18 and 54 mu g mL(-1) for chlorogenic acid, 37 and 112 mu g mL(-1) for caffeic acid, and 11 and 34 mu g mL(-1) for ferulic acid. The determination of the four active ingredients was not interfered by the excipients of the products. Samples were stable in the release mediums (37 degrees C) at least for 12 h.