title: Use of beta-cyclodextrins to prevent modifications of the properties of carbopol hydrogels due to carbopol-drug interactions.
abstract: Carbomers are carboxyvinylic derivatives that are widely used in the manufacture of hydrogel dosage forms. Because of their anionic nature and large number of acid groups, they tend to interact with cationic substances, and with other hydrophilic polymers containing alcohol groups. Here, we report a study of interactions between the carbomer Carbopol and the cationic drug propranolol hydrochloride in the solid state and in solution, and of the effects of such interactions on the properties of the hydrogel. We found that the drug forms an insoluble ionic complex with the polymer, modifying all of the hydrogel properties studied (swelling, release, bioadhesion). The inclusion of beta-cyclodextrin in the formulation reduces polymer/drug interactions, so that hydrogel properties remain unchanged. This is probably attributable to formation of inclusion complexes of beta-cyclodextrin and the drug, so that the drug is prevented from interacting with the polymer.
authors.affiliation: Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, Santiago de Compostela, Spain.
authors.forename: Haydee
authors.initials: H
authors.lastname: Blanco-Fuente
authors.forename: Blanca
authors.initials: B
authors.lastname: Esteban-Fernández
authors.forename: José
authors.initials: J
authors.lastname: Blanco-Méndez
authors.forename: Francisco-Javier
authors.initials: FJ
authors.lastname: Otero-Espinar
mesh_terms: D000180:Acrylic Resins; D003505:Cyclodextrins / Q000737:chemistry*; D004304:Dosage Forms; D004337:Drug Carriers / Q000737:chemistry*; D004344:Drug Incompatibility; D020100:Hydrogels / Q000737:chemistry*; D007700:Kinetics; D011108:Polymers; D011145:Polyvinyls / Q000737:chemistry*; D011433:Propranolol / Q000737:chemistry; D012996:Solutions; D013696:Temperature; D013997:Time Factors; D047392:beta-Cyclodextrins
chemical_list: D000180:Acrylic Resins; D003505:Cyclodextrins; D004304:Dosage Forms; D004337:Drug Carriers; D020100:Hydrogels; D011108:Polymers; D011145:Polyvinyls; D012996:Solutions; D047392:beta-Cyclodextrins; C006912:carboxypolymethylene; D011433:Propranolol; C031215:betadex