Forced Degradation Study of Expired and Marketed Tablets of Amlodipine by RP-HPLC
The objective of the current study was to develop simple, accurate, sensitive and stability indicating RP-HPLC method for the determination of per cent drug remained of Amlodipine besylate in the presence of its degradation products in bulk drug, expired tablets and tablets whose expiry date has not been exceeded. Drug was subjected to all stress conditions such as hydrolysis (acidic and alkaline), oxidation (3% H2O2 v/v), photolysis, thermal degradation and humidity study. All stressed samples were successfully analysed on C18 column using mobile phase Phosphate buffer pH 3.5 (50mM): Methanol: Acetonitrile in the ratio of 30:60:10 v/v/v. A flow rate was maintained at 1.5 ml/min and detection was made at 240 nm. The proposed methods were validated with regard to linearity, sensitivity, and intermediate accuracy and precision. This drug was found to be degraded 30-35% in 0.1 N HCl and in 0.1 N NaOH almost 95% and 88-90% degraded when exposed to oxidation, whereas 36-46% degradation in the solid state photostability study. In all stressed samples majorly 1 peak of degradation products were seen and 2 degradation peaks were observed in case of alkaline hydrolysis, both were observed in between 1 to 3.5 min of retention time.