Stability‑Indicating RP‑HPLC Method for Determination of Pirfenidone and force degradation in Pharmaceutical Formulations

Abstract

Background: Pirfenidone is an antifibrotic drug widely used in the treatment of idiopathic pulmonary fibrosis. Due to its therapeutic importance, the development of a reliable analytical method is essential for routine quality control, assay determination, and stability evaluation in pharmaceutical dosage forms. Methods: A rapid and economical reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the quantitative determination of pirfenidone in active pharmaceutical ingredient (API) and tablet formulations. Method validation was performed according to ICH Q2(R1) guidelines, and forced degradation studies were conducted following ICH Q1A(R2) recommendations to establish the stability-indicating capability of the method. Results: Chromatographic separation was achieved on an Inert Sustain C18 column (4.6 × 250 mm, 5 µm). The mobile phase consisted of Methanol and 0.1%OPA (90:10 v/v), delivered at a flow rate of 1.0 mL/min. Detection was carried out at 317 nm using a PDA detector. Pirfenidone eluted at approximately 3.8 minutes. The method showed good linearity over the concentration range of 5–50 µg/mL with a correlation coefficient of 0.999. The limits of detection (LOD) and quantification (LOQ) indicated sufficient sensitivity of the method. Forced degradation studies under acidic, basic, oxidative, thermal, and photolytic conditions demonstrated that pirfenidone was well separated from its degradation products. Conclusion: The developed RP-HPLC method is simple, rapid, cost-effective, and stability-indicating. It is suitable for routine quality control analysis and stability testing of pirfenidone in pharmaceutical formulations.