High Performance HPLC-UV Method Development and Validation for Sulfadoxine from its Potential Interfering Impurities

To address the separation of interfering potential impurities associated with the drug is always a daunting task. We present the method validation and quantitative determination of sulfadoxine (SUL), an anti-malarial drug with most important interfering impurities present pharmaceutical dosages and in bulk samples using HPLC-UV method. The UV detection was obtained at 270 nm and SUL is separated on Sunfire C18 (25 cm x 4.6 mm x 5 µ m) column at 45°C with flow rate of 1.0 mL/min in a mobile phase (CH3COOH:CH3CN). The stress testing (acidic/basic/oxidative) was performed using HPLC for SUL and its impurities showing the highly efficient separation peaks between degradant and drug product. The developed method was found to be highly accurate and sensitive in regulation with ICH guidelines. Also, it was found to be free from interference from degradation products which allows the stability indicating capability of developed HPLC-UV method for SUL for validation in bulk drugs. The main advantages of the present method; (a) Separation achieved in 30 minutes, (b) MS compatible mobile phase renders this developed method can be directly adapted to LC-MS without any major modifications in near future, and (c) separation of twelve impurities on Sunfire C18 column. The CFs (correction factors) had been calculated for all the impurities. It was found to be 1.6 (IMP IX), 1.70 (IMP XI) and in between 0.8-1.3 for all other impurities. The LOD of the developed method for all the analytes were in the range of 0.05 to 0.11 μg/mL and the LOQ values were in the range of 0.17 to 0.36 μg/mL.