Green HPLC Determination of Phenytoin and Method Validation

Abstract

Objective: In this study, the chromatographic behavior of the antiepileptic drug phenytoin was determined by the green HPLC method. The optimization of the developed method was based on the capacity factor values of phenytoin in varying water-ethanol binary mixtures and the ethanol concentration in the mobile phase where the compound was analyzed. Material and Method: Ethanol-water binary mixtures containing 35%, 40%, and 45% (v/v) ethanol were used in the optimization for the determination performed by the RPLC method. Retention times of the compound were determined with the Zorbax SB-CN (150x4.6 mm, 3.5 µm ID) column. Analyzes were performed at a constant flow rate (0.3 ml/min) and column temperature (37°C). The optimum condition for quantitative analysis was determined as an ethanol-water binary mixture containing 40% (v/v) ethanol with a pH of 6.5. Result and Discussion: In this study, the hydrophobicity of phenytoin was calculated using the logk-φ relationship. The optimum condition was determined using the obtained chromatographic data, and the quantitative determination of phenytoin in the commercial tablet formulation was made by the internal standard method. Under these conditions, excellent linearity (r>0.99) was obtained in the concentration range of 0.8-2.8 μg/ml. The detection limit of the developed method is 0.021 μg/ml; the limit of quantitation was calculated as 0.064 μg/ml. The recovery value of the method was determined as 99.61%. It was concluded that the parameters of precision, accuracy, and method robustness were appropriate for the validation procedures.