title: An in vitro model for investigating the gastric mucosal retention of 14C-labelled poly(acrylic acid) dispersions.
abstract: Polymers that bind from solution onto gastric mucosae can be used as a means of facilitating localised drug delivery, or act as therapeutic agents in their own right (e.g. by forming a protective layer or by inhibiting enzymes). Previous workers have used semi-quantitative methods to identify the ability of commercially available poly(acrylic acid)s to bind to gastric mucosa. In this study, the binding and retention of labelled poly(acrylic acid)s to sections of gastric mucosa from the pyloric region of pigs stomach were evaluated using 'static' and 'dynamic flow' test systems. Dispersions (3%) of 'low', 'high' and 'ultra high' (cross-linked) polymers were seen to adhere to porcine pyloric mucosa after exposure and rinsing in the 'static' system. The high molecular weight polymer showed the greatest retention in the 'dynamic' test system when washing continuously with simulated gastric acid. Changing the pH of the dispersions from 4.3 to 6.2 had little effect on polymer retention. It was concluded that polymers that were sufficiently mobile in solution to spread on, and interact with, the mucosal surface, but had a sufficiently high molecular weight to form viscous solutions and/or bioadhere to the mucosa, may be retained on the mucosal surface for the longest periods.
authors.affiliation: Biomaterials and Drug Delivery Group, School of Pharmacy and Biomedical Sciences, University of Portsmouth, St. Michael's Building, White Swan Road, PO1 2DT, Portsmouth, UK.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Riley
authors.forename: John D
authors.initials: JD
authors.lastname: Smart
authors.forename: John
authors.initials: J
authors.lastname: Tsibouklis
authors.forename: Simon A
authors.initials: SA
authors.lastname: Young
authors.forename: Frank
authors.initials: F
authors.lastname: Hampson
authors.forename: Alf
authors.initials: A
authors.lastname: Davis
authors.forename: Grant
authors.initials: G
authors.lastname: Kelly
authors.forename: Peter W
authors.initials: PW
authors.lastname: Dettmar
authors.forename: William R
authors.initials: WR
authors.lastname: Wilber
mesh_terms: D000180:Acrylic Resins / Q000378:metabolism* / Q000493:pharmacokinetics; D000818:Animals; D002250:Carbon Radioisotopes; D017220:Dentin-Bonding Agents / Q000378:metabolism* / Q000493:pharmacokinetics; D004353:Drug Evaluation, Preclinical / Q000295:instrumentation / Q000379:methods; D005753:Gastric Mucosa / Q000378:metabolism*; D008954:Models, Biological; D013552:Swine
chemical_list: D000180:Acrylic Resins; D002250:Carbon Radioisotopes; D017220:Dentin-Bonding Agents; C006903:carbopol 940