A Validated Stability-indicating HPTLC Method for the Determination of Roflumilast in Tablets and Application to Accelerated Stability Studies
Department of Pharmaceutical Analysis, College of Pharmacy, Sri Ramakrishna Institute of Paramedical Sciences, Dr. M. G. R. Medical University, Coimbatore-641 044, India
Department of Pharmaceutical Analysis, College of Pharmacy, Sri Ramakrishna Institute of Paramedical Sciences, Dr. M. G. R. Medical University, Coimbatore-641 044, India E-mail: [email protected]
A high performance thin layer chromatography method was developed for roflumilast on silica gel 60F254 thin layer chromatography plates using mobile phase comprising of toluene:ethyl acetate (7:3% v/v) with detection set at 254 nm on a densitometer. The Rf value of roflumilast was 0.54±0.02. Percent recovery of the drug from tablet formulation was carried out by standard addition method and was found to be close to 100 and percent relative standard deviation was less than 2%, which indicated good accuracy and precision of the method. Roflumilast was subjected to acid, alkali and neutral hydrolysis, oxidation and thermal and photolytic degradation. Degradation studies indicated roflumilast to be susceptible to acid and alkaline hydrolysis and oxidation. The degradation product was well resolved from the pure drug with significant differences in Rf values. The developed validated method was applied to formulation, content uniformity test and accelerated stability studies of roflumilast. The rate of hydrolysis was found to increase with increase in the strength of hydrochloric acid. It was observed that temperature had a major effect over acid hydrolysis of roflumilast compared to varying the strength of hydrochloric acid. Further this study can be extended for the determination of shelf life of roflumilast formulations.