Optimization of Stability-Indicating HPLC Method for Analyzing Process Related Impurities of Penfluridol and Structural Elucidation of Stress Degradation Products by LCMS/MSucidation of Stress Degradation Products by LCMS/MS

Abstract

This study focused on the development of a simple and sensitive HPLC method for resolution and quantification of process-related impurities of penfluridol and further assessment of forced degradation behavior of penfluridol. The chromatographic separation was achieved on XTerra™ C18 (250×4.6 mm, 5.0μm) column and UV detection at 245nm. The mobile phase comprises of methanol and tetrahydrofuran in 55:45 (v/v) as solvent A and acetonitrile and tetrahydrofuran in 80:20 (v/v) as solvent B. The 60:40 (v/v) composition of solvent A and B were pumped isocratically at 1.0mL/min. In the proposed conditions, the retention time identified as 5.29 min for penfluridol, 4.51 min, 9.95 min and 7.64 min respectively for impurity 1, 2 and 3 with acceptable system suitability. The method produces sensitive detection limit of 0.008μg/mL for impurity 1, 2 and 0.004 μg/mL for impurity 3 with calibration range of 25-150 μg/mL for penfluridol and 0.025-0.150 μg/mL for impurities. The drug was exposed to different stressed conditions (acid, base, peroxide, thermal and UV light) according to ICH Q1A (R2) guidelines. The Degradation Products (DPs) formed during the stress study was characterized by LCMS/MS in ESI positive mode and the possible structures of five DPs with possible degradation pathways were proposed. The outcomes of other validation studies were likewise satisfactory and proven adequate for regular analysis of penfluridol and its process-related impurities in bulk drug and pharmaceutical dosage forms and can also applicable for evaluation of stress degradation mechanism of penfluridol.