ABSTRACT
A Simple, rapid, specific, accurate, economical and precise UV spectrophotometric and RP-HPLC methods (inaccordance with ICH guidelines) were developed and validated for determination of Nortriptyline hydrochlorideand Pregabalin in tablet dosage form. The first method was based on Q - absorbance ratio, and absorbances ofboth drugs were determined at 239 nm (λmax of Nortriptyline Hydrochloride) and 235 nm (Iso-absorptive Point)when dissolved in methanol. It is found that Pregabalin does not have chromophoric group. To be UV-sensitive,it was compulsory to introduce chromophoric group in Pregabalin structure and make it UV-sensitive. This wasachieved by converting the primary amine group of Pregabalin through reaction with benzoyl chloride to formbenzoylated derivative of Pregabalin. Benzoylated Pregabalin was determined at 225 nm using UV-visiblespectrophotometer. The second method was based on RP-HPLC. The chromatographic separation was performedon an Inertsil ODS C18 column (250 x 4.6mmx 5 μm) with a mobile phase of 0.56 %w/v Sodium hexane sulphonicacid dissolved in water acetonitrile (50:50 %v/v, pH 4.5 adjusted with Glacial Acetic Acid) at flow rate of 1.0mL/min with DAD detection wavelength at 210 nm. Retention times of Nortriptyline Hydrochloride andPregabalin were 7.3894 min and 4.0506 min, respectively. Beer-Lambert’s law obeyed the concentration rangeof 2-12 μg/mL for Nortriptyline Hydrochloride and 10-60 μg/mL for Pregabalin. The results indicated that bothspectrophotometric and RP-HPLC methods were linear, accurate, precise and robust with RSD values less than0.2% and % recovery was within the standard limits (99 - 102%).