Abstract
The present study was conducted to develop therapeutically effective controlled release formulation of pirfenidone (PFD) and explore the possibility to reduce the total administered dose and dosing regimen. For this purpose, pH-sensitive biomaterial was prepared by inducing carboxymethyl group on pullulan by Williamson ether synthesis reaction, and further, interpenetrating polymeric network microspheres were prepared by glutaraldehyde-assisted water-in-oil (w/o) emulsion cross-linking method, which showed higher swelling ratio in acidic and basic pH. The formation of microspheres was confirmed by different spectral characterization techniques, and thermal kinetic study indicated the formation of thermally stable microspheres. Cell viability and biocompatibility studies on hepatocellular carcinoma (HepG2) cell showed the polymeric matrix to be biocompatible. In vitro dissolution of optimized formulation (F5) showed releases of 54.09 and 76.37% in 0.1 N HCl after 2 h and phosphate buffer (pH 6.8) up to 8 h, respectively. In vivo performances of prepared microsphere and marketed product of PFD were compared in rabbit. T (max) (time taken to reach peak plasma concentration) was found to be achieved at 0.83 h, compared to 0.5 h for Pirfenex with no significant difference complementing the immediate action, while area under curve was significantly greater for optimized formulation (9768 ± 1300 ng h/mL) compared to Pirfenex (4311 ± 110 ng h/mL), complementing the sustained action. In vivo pharmacokinetic study suggested that the prepared microsphere could be a potential candidate for therapeutically effective controlled delivery of PFD used in dyspnea and cough management due to idiopathic pulmonary fibrosis.