Therapeutically Effective Controlled Release Formulation of Pirfenidone from Nontoxic Biocompatible Carboxymethyl Pullulan-Poly(vinyl alcohol) Interpenetrating Polymer Networks

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.

Extended wear therapeutic contact lens fabricated from timolol imprinted carboxymethyl chitosan-g-hydroxy ethyl methacrylate-g-poly acrylamide as a onetime medication for glaucoma

An extended wear therapeutic contact lens (TCL) for the sustained delivery of timolol maleate (TML) was fabricated based on molecular imprinting technique. The designed TCL comprised of a TML imprinted copolymer of carboxymethyl chitosan-g-hydroxy ethyl methacrylate-g-polyacrylamide (CmCS-g-HEMA-g-pAAm) embedded onto a poly HEMA matrix (pHEMA). Successful reloading of TML onto the lens was monitored using a simple and novel UV-Visible spectrophotometric method which showed an excellent reloading capacity of 6.53μgTML/TCL. The in vitro drug release profile in lacrimal fluid after each cycle was fitted onto Higuchi model of drug release suggesting diffusion release mechanism with no polymer degradation. Also, the TML release kinetics indicated a sustained drug delivery which can effectively achieve the therapeutic index of TML leading to a onetime medication for glaucoma. Biological activity of eluted drug after each cycle and cell viability of the TCL were verified using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,3-bis(2-methoxynitro-5-sulfophenyl)-5-(phenylaminocarbonyl)-2H-tetrazolium hydroxide (XTT) assay, respectively.