KINETIC ESTIMATION OF GABAPENTIN AND ETORICOXIB IN PHARMACEUTICALS
Keywords:Etoricoxib, Gabapentin, Kinetic spectrophotometry, Constant time method, Rate constant method.
Kinetic spectrophotometric methods have been developed and validated for the determination of Analgesics drugs, Gabapentin and Etoricoxib in
their pharmaceutical dosage forms. The method is based on the oxidation of Gabapentin and Etoricoxib with alkaline and acidic potassium
permanganate respectively. In alkaline medium permanganate (Mn+7) oxidizes Gabapentin and undergoes one electron reduction to give a green
colored manganate ions (Mn+6) which has wavelength maximum at 610 nm, and unreacted permanganate at 526 nm. In acidic medium the course of
the reaction was conveniently followed by measuring the absorbance of permanganate at 526 nm, as the permanganate undergoes five electrons
reduction to give divalent manganese ions (Mn+2) . The calibration graphs for both drugs are linear in the concentration ranges from 17.2 – 86
µg/ml and 35.9 – 35 µg/ml for fixed time and rate constant methods respectively.