title: Effects of the permeability characteristics of different polymethacrylates on the pharmaceutical characteristics of verapamil hyhdrochloride-loaded microspheres.
abstract: Microspheres containing verapamil hydrochloride (VRP) were prepared with various polymethacrylates, with different permeability characteristics (Eudragit RS 100, Eudragit RL 100, Eudragit L 100 and Eudragit L 100-55) and also with mixtures of these polymers in a 1:1 ratio using the solvent evaporation method. The aim was to investigate the effects of the permeability of the polymers on drug release rates and the characteristics of the microspheres. To achieve these aims, yield, incorporation efficiency, particle size and the distribution of microspheres were determined, and the influence of the inner phase viscosities prepared with different polymer and polymer mixtures on particle size and the distribution of microspheres were evaluated. Surface morphologies of microspheres were observed by scanning electron microscope. Drug release rates from microspheres were determined by the half-change method using a flow-through cell. The results indicate that microspheres with different surface morphologies and statistically different yields and incorporation efficiencies could be prepared and their particle size and distribution xariances resulted from the viscosity of the inner phase. Dissolution profiles showed that the drug release rate could be modified depending on the permeability characteristics of polymethacrylates.
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmacy, Ankara University, 06100 Tandoğan, Ankara, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Kiliçarslan
authors.forename: T
authors.initials: T
authors.lastname: Baykara
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D010539:Permeability; D011109:Polymethacrylic Acids / Q000737:chemistry*; D012997:Solvents; D013499:Surface Properties; D014700:Verapamil
chemical_list: D000180:Acrylic Resins; D011109:Polymethacrylic Acids; D012997:Solvents; C038300:methylmethacrylate-methacrylic acid copolymer; C050528:Eudragit RS; D014700:Verapamil