title: Preparation of alginate beads for floating drug delivery system: effects of CO(2) gas-forming agents.
abstract: Floating beads were prepared from a sodium alginate solution containing CaCO(3) or NaHCO(3) as gas-forming agents. The solution was dropped to 1% CaCl(2) solution containing 10% acetic acid for CO(2) gas and gel formation. The effects of gas-forming agents on bead size and floating properties were investigated. As gas-forming agents increased, the size and floating properties increased. Bead porosity and volume average pore size, as well as the surface and cross-sectional morphology of the beads were examined with Mercury porosimetry and Scanning Electron Microscopy. NaHCO(3) significantly increased porosity and pore diameter than CaCO(3). Incorporation of CaCO(3) into alginate solution resulted in smoother beads than those produced with NaHCO(3). Gel strength analysis indicated that bead strength decreased with increasing gas-forming agent from 9 to 4 N. Beads incorporating CaCO(3) exhibited significantly increased gel strength over control and NaHCO(3)-containing samples. Release characteristics of riboflavin as a model drug were studied in vitro. Release rate of riboflavin increased proportionally with addition of NaHCO(3). However, increasing weight ratios of CaCO(3) did not appreciably accelerate drug release. The results of these studies indicate that CaCO(3) is superior to NaHCO(3) as a gas forming agent in alginate bead preparations. The enhanced buoyancy and sustained release properties of CaCO(3)-containing beads make them an excellent candidate for floating drug dosage systems (FDDS).
authors.affiliation: Graduate School of Biotechnology, Korea University, Seoul 136-701, South Korea.
authors.forename: B Y
authors.initials: BY
authors.lastname: Choi
authors.forename: H J
authors.initials: HJ
authors.lastname: Park
authors.forename: S J
authors.initials: SJ
authors.lastname: Hwang
authors.forename: J B
authors.initials: JB
authors.lastname: Park
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002119:Calcium Carbonate / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry*; D003692:Delayed-Action Preparations; D004339:Drug Compounding; D016503:Drug Delivery Systems; D005079:Excipients; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D016062:Porosity; D012256:Riboflavin / Q000008:administration & dosage / Q000737:chemistry; D017693:Sodium Bicarbonate / Q000737:chemistry; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D000464:Alginates; D003692:Delayed-Action Preparations; D005079:Excipients; D002245:Carbon Dioxide; D017693:Sodium Bicarbonate; D002119:Calcium Carbonate; D012256:Riboflavin