Preparation and in-vitro Release of Smart Nanoparticles Containing Indomethacin for Use in Ophthalmic Anti Inflammatory Formulations

The potential of polymeric nano particles as an ocular drug delivery system has been explored by a colloidal system consisting of an aqueous suspension of nano particles. These nanoparticles can be rapidly fabricated under extremely mild conditions with their ability to incorporate bioactive compounds. In present study the preparation and characterization of the novel crosslinked poly N-isopropylacrylamide-based micellar nano particles have been reported. Poly Nisopropylacrylamide- acrylic acid-hydroxyethyl methacrylate (NIPAAM-AA-HEM) copolymer was prepared by free radical copolymerization of monomers in 1, 4-dioxane under N2 atmosphere. Triethylene glycol dimethacrylate (TEGDM) was used as a novel cross-linking agent. For preparation of drug-loaded nano particles, indomethacin got directly loaded into the hydrophobic core of micelles. Drug incorporation efficiency was expressed as drug content (DL %). In-vitro indomethacin release rate was tested, too. The chemical structures of cross linked polymers were confirmed by FT-IR and 1H- NMR spectroscopies. The particl size analyzer data represented that the particles has mean sizes between 200-470 nm. The maximum swelling ratio of hydrogel occurred at 10 min at 37 ˚C and pH 1.0 and at 125 min at 20 ˚C and pH 1.0. For both synthesized co-polymeric preparations, a progressive increase of drug release rate was observed as a function of drug-polymer ratio. The prepared nano particles were stable in an aqueous solution and maintained their physical characteristics such as particle size and drug loading content during seven days of storage. The results clearly demonstrated that developed poly N-isopropylacrylamide based formulation showed suitable type of release behavior over 24 h periods. The developed system is thus a viable alternative to conventional ocular drop formulations because it prevents the rapid drainage as in case of mucoadhesive property of the copolymer.