title: Evaluation of mucoadhesive polymers in ocular drug delivery. II. Polymer-coated vesicles.
abstract: Association of Carbopol 934P and Carbopol 1342 (a hydrophobic modified Carbopol resin) with phospholipid vesicles was assessed by photon correlation spectroscopy and microelectrophoresis at pH 7.4 and 5. The precorneal clearance of the polymer-coated vesicles was compared to that of uncoated vesicles by lacrimal dacryoscintigraphy in the rabbit. The mucoadhesive polymer-coated vesicles demonstrated significantly enhanced precorneal retention compared to noncoated vesicles only at pH 5 (P less than 0.005). The entrapment and subsequent release of tropicamide from Carbopol 1342-coated and uncoated liposomes were determined in vitro together with an in vivo evaluation of the vesicles formulated at the lower pH. Mucoadhesive polymer-coated vesicles failed to increase significantly the bioavailability of the entrapped tropicamide compared to uncoated vesicles and aqueous solution.
authors.affiliation: Welsh School of Pharmacy, University of Wales, College of Cardiff, U.K.
authors.forename: N M
authors.initials: NM
authors.lastname: Davies
authors.forename: S J
authors.initials: SJ
authors.lastname: Farr
authors.forename: J
authors.initials: J
authors.lastname: Hadgraft
authors.forename: I W
authors.initials: IW
authors.lastname: Kellaway
mesh_terms: D000180:Acrylic Resins; D000268:Adhesiveness; D000818:Animals; D001682:Biological Availability; D016503:Drug Delivery Systems; D005123:Eye / Q000378:metabolism; D008081:Liposomes / Q000737:chemistry*; D008297:Male; D009883:Ophthalmic Solutions / Q000737:chemistry*; D010316:Particle Size; D011145:Polyvinyls / Q000737:chemistry*; D011817:Rabbits; D013667:Technetium; D014331:Tropicamide / Q000008:administration & dosage / Q000493:pharmacokinetics
chemical_list: D000180:Acrylic Resins; D008081:Liposomes; D009883:Ophthalmic Solutions; D011145:Polyvinyls; C006912:carboxypolymethylene; D013667:Technetium; D014331:Tropicamide