Abstract

DEGRADATION AND KINETIC STUDY OF TRAMADOL HCL BY RP-HPLC

Dr. Dhrubo Jyoti Sen and Khushbu S. Patel*

Abstract

A simple, precise and accurate isocratic RP–HPLC method was developed. The method has shown adequate separation for Tramadol HCl and degradation products. Separation was achieved on a ACE C18 (150 mm×4.6 mm i.d., 5μm particle size) column using mobile phase consisting of Acetonitrile – Water (70:30v/v) at flow rate of 1mL/min and UV detection at 272nm. This drug was subjected to acid hydrolysis and alkali hydrolysis by applying stress conditions. The linearity was investigated in the range of 40–120μg/mL (r2 = 0.9996) for Tramadol HCl. The intraday and interday % RSD values were less than 0.9%. The LOD and LOQ were 0.24μg/mL and 0.72μg/mL Tramadol HCl was degraded in acid (1N HCl by Microwave) and alkali (1N NaOH) in different temperature conditions. Tramadol HCl was more degraded in alkaline condition compared to acidic. For the degradation kinetic in acidic and alkaline conditions the best fit was obtained for firstorder reaction rate. The rate constant (k) is in the alkaline medium, 0.0034min-1 for R.T. NaOH, 0.0149min-1 for 60°C NaOH, 0.4849min-1 for 80°C NaOH and in acid medium 0.0653min-1 by Microwave. The t1/2 was found to be less in alkaline condition compared to acidic conditions which shows, the drug has lower stability in alkaline medium. The t1/2 is 1.18mins for alkaline condition and 6.39mins for acidic condition. The activation energy of Tramadol HCl in alkaline medium was found to be 3.771KJ/mole.

Keywords: Tramadol HCl, Rate constant, Microwave, Alkali hydrolysis, Acid hydrolysis, Half life, Shelf life, RP – HPLC, Retention time, Chromatogram, Linearity, Correlation coefficient, Arrhenius plot, Calibration curve, Interday and intraday precision, LOD,