Determination of 2-(Diethylamino)-N-(2,6- Dimethylphenyl) Acetamide in a Gel Pharmaceutical Formulation by High-Performance Liquid Chromatography

An isocratic reversed-phase high performance liquid chromatographic method is developed and validated for the determination of 2-(diethylamino)-N-(2,6-dimethylphenyl) acetamide (0.3%, w/w) in a gel formulation. The chromatographic separation is achieved with potassium phosphate buffer (pH 7.0)-acetonitrile (47:53, v/v) as mobile phase, a C(18) column, and UV detection at 254 nm. The calibration curve is linear (r(2) = 1.000) from 20-140% of the analytical concentration of 1.4 microg/mL. The mean percent relative standard deviation values for intra- and interday precision studies are < 1%. The recovery ranges 99.95-100.23% from a gel formulation. The method is specific and successfully routinely used in quality control for the analysis of bulk gel samples and final product release.