First Derivative Spectrophotometric Determination of Phenytoin

The first derivative curve (D1) of absorption spectrum of Phenytoin in buffer pH 10 develos negative peaks at 244, 263 and 270 nm. D1 at 244 nm was found linearly related to concentration over a range 0.4 − 1.4 mg per 100 ml and highly reproducible (C.V. %=0.62). Tablets and capsules have been analyzed using D1 at 244 nm and the mean percentage found were 99.7 ± 0.81 and 103.3 ± 0.44, respectively. The B.P. method gave 100.9 and 103.8 %, respectively.