title: Modulation of gel formation and drug-release characteristics of lidocaine-loaded poly(vinyl alcohol)-tetraborate hydrogel systems using scavenger polyol sugars.
abstract: Polyol sugars, displaying a plurality of hydroxyl groups, were shown to modulate tetrahydroxyborate (borate) cross-linking in lidocaine hydrochloride containing poly(vinyl alcohol) semi-solid hydrogels. Without polyol, demixing of borate cross-linked PVA hydrogels into two distinct phases was noticeable upon lidocaine hydrochloride addition, preventing further use as a topical system. d-Mannitol incorporation was found to be particularly suitable in circumventing network constriction induced by ionic and pH effects upon adding the hydrochloride salt of lidocaine. A test formulation (4% w/v lidocaine HCl, 2% w/v d-mannitol, 10% w/v PVA and 2.5% w/v THB) was shown to constitute an effective delivery system, which was characterised by an initial burst release and a drug release mechanism dependent on temperature, changing from a diffusion-controlled system to one with the properties of a reservoir system. The novel flow properties and innocuous adhesion of PVA-tetrahydroxyborate hydrogels support their application for drug delivery to exposed epithelial surfaces, such as lacerated wounds. Furthermore, addition of a polyol, such as d-mannitol, allows incorporation of soluble salt forms of active therapeutic agents by modulation of cross-linking density.
authors.affiliation: School of Pharmacy, Queens University Belfast, Belfast, UK.
authors.forename: Ryan G
authors.initials: RG
authors.lastname: Loughlin
authors.forename: Michael M
authors.initials: MM
authors.lastname: Tunney
authors.forename: Ryan F
authors.initials: RF
authors.lastname: Donnelly
authors.forename: Diarmaid J
authors.initials: DJ
authors.lastname: Murphy
authors.forename: Mark
authors.initials: M
authors.lastname: Jenkins
authors.forename: Paul A
authors.initials: PA
authors.lastname: McCarron
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage*; D001881:Borates / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D006245:Hardness Tests; D020100:Hydrogels; D006863:Hydrogen-Ion Concentration; D008012:Lidocaine / Q000008:administration & dosage*; D008353:Mannitol / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011142:Polyvinyl Alcohol / Q000737:chemistry; D013696:Temperature; D014783:Viscosity
chemical_list: D000779:Anesthetics, Local; D001881:Borates; D003692:Delayed-Action Preparations; D020100:Hydrogels; D011108:Polymers; C024617:polyol; D008353:Mannitol; C021755:tetraborate; D011142:Polyvinyl Alcohol; D008012:Lidocaine