A Validated Stability Indicating HPTLC Method for Estimation of Mycophenolate Sodium

Intrduction: The present study reports validated stability indicating high performance thin layer chromatographic (HPTLC) method of analysis for estimation of an immunosuppressant drug; mycophenolate sodium in bulk drug and formulations. Method: Silica gel pre-coated aluminium plates 60F254 were used as stationary phase. Various mobile phases were tried, out of which chloroform: methanol and glacial acetic acid (9:0.3:0.1; v/v/v) provided best separation at 254 nm (Rf 0.66±0.03) by densitometric evaluation. Results: The linearity range was 100-2500 ng with R2 value 0.9977 while, % RSD of intra-day and inter- day precision was found to be less than 1.5% indicating that the method is precise. Limit of detection (LOD) and limit of quantification (LOQ) of mycophenolate sodium were found to be 30ng/spot and 90 ng/spot respectively. The recovery of mycophenolate sodium was found to be 100.2±0.011%. Inherent stability of mycophenolate sodium was studied by exposing it to various stress conditions as per ICH guidelines viz. acid, base, dry heat, oxidation, photolysis (sunlight, UV) and neutral hydrolysis. The peaks of the degradation products and pure drug exhibited different Rf values indicating significant resolution. Degradation studies revealed 11-20% degradation of mycophenolate sodium in 1-3 h by acidic (1 N HCl), alkaline (1N NaOH), dry heat, neutral hydrolysis and oxidative degradation by 3% H2O2. However it remained stable to photo-degradation. Conclusion: Proposed method was found to be more sensitive, precise, economic and less time consuming than the reported stability indicating HPLC method. Moreover, it is simple, accurate, and reproducible. It could be applied for analysis of bulk drug/formulation, dissolution study and stress degradation kinetics.