title: Dexamethasone-pDMAEMA polymeric conjugates reduce inflammatory biomarkers in human intestinal epithelial monolayers.
abstract: The mucoadhesive polymer, poly(dimethylamino)ethyl methacrylate, (pDMAEMA), was synthesised by living radical polymerisation and subsequently conjugated by quaternisation reaction to a functionalised anti-inflammatory corticosteroid dexamethasone, to separately yield two conjugates with either 9:1 or 18:1 molar ratios of dexamethasone:polymer respectively. The hypothesis was to test whether the active agent maintained in vitro bioactivity when exposed to the apical side of human intestinal epithelial monolayers, Caco-2 and mucus-covered HT29-MTX-E12 (E12). HPLC analysis indicated high conjugate purity. Similar to pDMAEMA, fluorescently-labelled dexamethasone-pDMAEMA conjugates were bioadhesive to Caco-2 and mucoadhesive to E12. Apical addition of conjugates suppressed mRNA expression of the inflammatory markers, NURR1 and ICAM-1 in E12 following stimulation by PGE(2) and TNF-alpha, respectively. Conjugates also suppressed TNF-alpha stimulated cytokine secretion to the basolateral side of Caco-2 monolayers. Measurement of dexamethasone permeability from conjugates across monolayers suggested that conjugation reduced permeability compared to free dexamethasone. LDH assay indicated that conjugates were not cytotoxic to monolayers. Anti-inflammatory agents can therefore be successfully conjugated to polymers and they retain adhesion and bioactivity and have potential to be formulated for topical administration.
authors.affiliation: School of Agriculture, Food Science and Veterinary Medicine, and UCD Conway Institute, University College Dublin, Dublin 4, Ireland.
authors.forename: Simon
authors.initials: S
authors.lastname: Keely
authors.forename: Sinéad M
authors.initials: SM
authors.lastname: Ryan
authors.forename: David M
authors.initials: DM
authors.lastname: Haddleton
authors.forename: Adam
authors.initials: A
authors.lastname: Limer
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mantovani
authors.forename: Evelyn P
authors.initials: EP
authors.lastname: Murphy
authors.forename: Sean P
authors.initials: SP
authors.lastname: Colgan
authors.forename: David J
authors.initials: DJ
authors.lastname: Brayden
mesh_terms: D000893:Anti-Inflammatory Agents / Q000008:administration & dosage* / Q000494:pharmacology; D015415:Biomarkers / Q000032:analysis; D018938:Caco-2 Cells; D002448:Cell Adhesion; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000096:biosynthesis* / Q000276:immunology; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000276:immunology; D003907:Dexamethasone / Q000008:administration & dosage* / Q000494:pharmacology; D004337:Drug Carriers / Q000737:chemistry*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis / Q000276:immunology; D007378:Interleukins / Q000096:biosynthesis / Q000276:immunology; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D008689:Methacrylates / Q000737:chemistry*; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D009757:Nylons / Q000737:chemistry*; D013997:Time Factors; D014157:Transcription Factors / Q000096:biosynthesis / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000276:immunology
chemical_list: D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D016207:Cytokines; D004268:DNA-Binding Proteins; D004337:Drug Carriers; D007378:Interleukins; D008689:Methacrylates; C539882:NR4A2 protein, human; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D009757:Nylons; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; C407037:poly(2-(dimethylamino)ethyl methacrylate); D018799:Intercellular Adhesion Molecule-1; D003907:Dexamethasone