title: Calcium alginate microparticles for oral administration: I: Effect of sodium alginate type on drug release and drug entrapment efficiency.
abstract: The natural polymers alginate and chitosan were used for the preparation of controlled release nicardipine HCl gel microparticles. The effect of the mannuronic/guluronic acid content and the alginate viscosity on the prolonged action of the microparticles, which were prepared with different types of alginates, were investigated. The mean particle sizes and the swelling ratios of the microparticles were also determined. The in vitro release studies were carried out with a flow-through cell apparatus in different media (pH 1.2, 2.5, 4.5, 7 and 7.5 buffer solutions). The release of nicardipine was extended with the alginate gel microparticles prepared with guluronic acid rich alginate. After the determination of the most appropriate alginate type, the effect of alginate-chitosan complex formation was studied on the release pattern of drug incorporated. It was observed that the alginate-chitosan complex formation reduced the erosion of the alginate-chitosan matrix at pH 7-7.5. The release of drug from the chitosan-alginate gel microparticles took place by both diffusion through the swollen matrix and relaxation of the polymer at pH 1.2-4.5.
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmacy, Gazi University, Ankara, Turkey.
authors.forename: S
authors.initials: S
authors.lastname: Takka
authors.forename: F
authors.initials: F
authors.lastname: Acartürk
mesh_terms: D000464:Alginates / Q000737:chemistry* / Q000494:pharmacology*; D002118:Calcium / Q000032:analysis; D002686:Chitin / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D048271:Chitosan; D003692:Delayed-Action Preparations; D004058:Diffusion; D004337:Drug Carriers; D004339:Drug Compounding / Q000379:methods; D016503:Drug Delivery Systems; D020723:Glucuronic Acid; D006603:Hexuronic Acids / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D009529:Nicardipine / Q000008:administration & dosage; D010316:Particle Size; D014783:Viscosity
chemical_list: D000464:Alginates; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D006603:Hexuronic Acids; D002686:Chitin; C007896:guluronic acid; D020723:Glucuronic Acid; D048271:Chitosan; C008324:mannuronic acid; D009529:Nicardipine; D002118:Calcium