title: Film coatings for oral colon delivery.
abstract: Oral colon delivery is pursued through a number of formulation strategies with the aim of enabling effective and well-tolerated treatments for large bowel pathologies or enhancing the intestinal absorption of peptide and protein drugs. According to such strategies, coated dosage forms for colonic release may be provided with microbiota, pH, pressure or time-dependent polymeric films. Microbiota-activated coatings are mostly obtained from polysaccharides of natural origin mixed with insoluble structuring excipients. Alternatively, synthetic azo compounds have been employed, generally requiring organic solvents for use as spray-coating agents. On the other hand, pH-sensitive films show responsiveness to pH changes in the lower gut, such as the rise generally observed in the terminal ileum and distal colon or the slight acidification of caecal contents by bacterial fermentation products. Pressure-sensitive coatings are intended for rupturing because of the relatively elevated pressure that may affect solid dosage forms in the large bowel. Finally, time-dependent films are expected to undergo timed erosion, break-up or permeabilization processes irrespective of the aforementioned physiological variables. In this review, the differing films applied for colon delivery purposes are surveyed, and details on their composition, manufacturing and performance are reported.
authors.affiliation: Università degli Studi di Milano, Dipartimento di Scienze Farmaceutiche, Sezione di Tecnologia e Legislazione Farmaceutiche "Maria Edvige Sangalli", Via G. Colombo 71, 20133 Milan, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Maroni
authors.forename: Maria Dorly
authors.initials: MD
authors.lastname: Del Curto
authors.forename: Lucia
authors.initials: L
authors.lastname: Zema
authors.forename: Anastasia
authors.initials: A
authors.lastname: Foppoli
authors.forename: Andrea
authors.initials: A
authors.lastname: Gazzaniga
mesh_terms: D000818:Animals; D003106:Colon / Q000378:metabolism*; D004339:Drug Compounding; D016503:Drug Delivery Systems; D006863:Hydrogen-Ion Concentration; D004364:Pharmaceutical Preparations / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism; D011312:Pressure
chemical_list: D004364:Pharmaceutical Preparations
keywords: Coated dosage forms; Colon delivery; Film-coating; Oral drug delivery