DEVELOPMENT AND VALIDATION OF RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF DICLOFENAC DIETHYLAMINE AND CURCUMIN IN TRANSDERMAL GELS

A reversed phase high performance liquid chromatographic (RP-HPLC) method using Symmetry C-18, 5.0-mu m column was developed for simultaneous determination of Diclofenac diethylamine (DDEA) and Curcumin (CRM). Mobile phase consisted of orthophosphoric acid 0.1% and acelonitrile (65:35), and the flow rate was 1.5 mL/min and elution was monitored initially at 425 nm for CRM, after 14.7 min wavelength was changed to 275 nm for detection of DDEA. Response was a linear function of concentration over the range 0.245-1.96 mu g/mL (R-2 = 0.9998) for DDEA and 55-445 ng/mL (R-2 = 0.9992) for CRM and the limits of detection were 245.5 ng/mL. for DDEA and 55.30 ng/mL for CRM. The limit of quantitation was 491.1 ng mL - 1 for DDEA and 165.87 ng ng mL - 1 for CRM. The method was validated in accordance with ICH guidelines. The method was used for simultaneous quantification of DDEA and CRM in transdermal gel formulations and to check content uniformity. The excipients present in the formulation did not interfere with the assay. The method is suitable for application in quality-control laboratories, because it is simple and rapid with good accuracy and precision.