title: Developing the potential ophthalmic applications of pilocarpine entrapped into polyvinylpyrrolidone-poly(acrylic acid) nanogel dispersions prepared by γ radiation.
abstract: The aim of this study was to improve the stability and bioavailability of pilocarpine in order to maintain an adequate concentration of the pilocarpine at the site of action for prolonged period of time. Thus, pH-sensitive polyvinylpyrrolidone-poly(acrylic acid) (PVP/PAAc) nanogels prepared by γ radiation-induced polymerization of acrylic acid (AAc) in an aqueous solution of polyvinylpyrrolidone (PVP) as a template polymer were used to encapsulate pilocarpine. Factors affecting size and encapsulation efficiency were optimized to obtain nanogel suitable for entrapping drug efficiently. The PVP/PAAc nanogel particles were characterized by dynamic light scattering (DLS), zeta potential, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM), and their size can be controlled by the feed composition and concentration as well as the irradiation dose. Pilocarpine was loaded into the nanogel particles through electrostatic interactions where the AAc-rich nanogels exhibited the highest loading efficiency. The transmittance, mucoadhesion, and rheological characteristics of the nanogel particles were studied to evaluate their ocular applicability. The in vitro release study conducted in simulated tear fluid showed a relatively long sustained release of pilocarpine from the prepared PVP/PAAc nanogel particles if compared with pilocarpine in solution.
authors: Department of Polymers, National Center for Radiation Research and Technology, Nasr City, Cairo 11371, Egypt. ha_rehim@hotmail.com
authors: Hassan A
authors: HA
authors: Abd El-Rehim
authors: Ahmed E
authors: AE
authors: Swilem
authors: Anke
authors: A
authors: Klingner
authors: El-Sayed A
authors: el-SA
authors: Hegazy
authors: Ashraf A
authors: AA
authors: Hamed
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D001672:Biocompatible Materials / Q000493:pharmacokinetics; D001682:Biological Availability; D005720:Gamma Rays; D005901:Glaucoma / Q000188:drug therapy; D006863:Hydrogen-Ion Concentration; D046529:Microscopy, Electron, Transmission; D009077:Mucins / Q000378:metabolism; D000080385:Nanogels; D010316:Particle Size; D010862:Pilocarpine / Q000737:chemistry / Q000493:pharmacokinetics*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011094:Polyethyleneimine / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D011205:Povidone / Q000737:chemistry*; D012212:Rheology; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; D009077:Mucins; D000080385:Nanogels; D011108:Polymers; C413692:polyethylene glycol polyethyleneimine nanogel; D010862:Pilocarpine; D011092:Polyethylene Glycols; C006903:carbopol 940; D011094:Polyethyleneimine; D011205:Povidone