title: Verapamil hydrochloride release characteristics from new copolymer zwitterionic matrix tablets.
abstract: The aim of this study was to synthesize stable copolymer (vinyl acetate-co-3-dimethyl[methacryloyloxyethyl] ammonium propane sulfinate) zwitterionic latex with different compositions for the first time by emulsifier-free emulsion copolymerization. Throughout the course of the study, a proposal was made for the explanation of the relationship between the "overshooting" phenomenon (a swelling kinetics with a maximum) and the specific self-association of the zwitterionic copolymers. The zwitterionic monomer unit mole fraction, pH, and ionic strength effects on this relationship, on the swelling kinetics of the zwitterionic copolymers, and on the sustained verapamil hydrochloride release from the model tablets were established by the study's authors.
authors.affiliation: Faculty of Pharmacy, Department of Pharmaceutical Technology and Biopharmacy, Medical University, Sofia, Bulgaria.
authors.forename: Bistra
authors.initials: B
authors.lastname: Kostova
authors.forename: Elena
authors.initials: E
authors.lastname: Kamenska
authors.forename: Ivo
authors.initials: I
authors.lastname: Ivanov
authors.forename: George
authors.initials: G
authors.lastname: Momekov
authors.forename: Dimitar
authors.initials: D
authors.lastname: Rachev
authors.forename: George
authors.initials: G
authors.lastname: Georgiev
mesh_terms: D002121:Calcium Channel Blockers / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004337:Drug Carriers / Q000737:chemistry*; D004655:Emulsions; D006863:Hydrogen-Ion Concentration; D008689:Methacrylates / Q000737:chemistry; D009994:Osmolar Concentration; D011108:Polymers / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013607:Tablets; D014700:Verapamil / Q000737:chemistry*; D014753:Vinyl Compounds / Q000737:chemistry
chemical_list: C530265:3-dimethyl(methacryloyloxyethyl)ammonium propane sulfonate; D002121:Calcium Channel Blockers; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004655:Emulsions; D008689:Methacrylates; D011108:Polymers; D000644:Quaternary Ammonium Compounds; D013607:Tablets; D014753:Vinyl Compounds; D014700:Verapamil; C011566:vinyl acetate