title: Preparation and evaluation of chitosan/carrageenan beads for controlled release of sodium diclofenac.
abstract: The polyelectrolyte complex (PEC) hydrogel beads based on chitosan (CS) and carrageenan (CR) have been studied as a controlled release device to deliver sodium diclofenac (DFNa) in the simulated gastrointestinal condition. Various factors potentially influencing the drug release (ie, CS/CR proportion, DFNa content, types and amount of cross-linking agents) were also investigated. The optimal formulation was obtained with CS/CR proportion of 2/1 and 5% (wt/vol) DFNa. The controlled release of the drug from this formulation was superior to other formulations and was able to maintain the release for approximately 8 hours. Upon cross-linking with glutaric acid and glutaraldehyde, the resulting beads were found to be more efficient for prolonged drug release than their non-cross-linking counterparts. The bead cross-linked with glutaraldehyde was able to control the release of the drug over 24 hours. The difference in the drug release behavior can be attributed to the differences in ionic interaction between the oppositely charged ions and to the concentrations of the drug within the beads, which depends on the compositions of the formulation and the pH of the dissolution medium. The release of drug was controlled by the mechanism of the dissolution of DFNa in the dissolution medium and the diffusion of DFNa through the hydrogel beads.
authors.affiliation: Program of Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Pimwipha
authors.initials: P
authors.lastname: Piyakulawat
authors.forename: Nalena
authors.initials: N
authors.lastname: Praphairaksit
authors.forename: Nuanphun
authors.initials: N
authors.lastname: Chantarasiri
authors.forename: Nongnuj
authors.initials: N
authors.lastname: Muangsin
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002214:Capsules; D002351:Carrageenan / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D003692:Delayed-Action Preparations; D004008:Diclofenac / Q000737:chemistry*; D004058:Diffusion; D004337:Drug Carriers; D004339:Drug Compounding; D005976:Glutaral / Q000737:chemistry; D005977:Glutarates / Q000737:chemistry; D020100:Hydrogels; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010316:Particle Size; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013678:Technology, Pharmaceutical / Q000379:methods; D013818:Thermogravimetry
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D002214:Capsules; D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005977:Glutarates; D020100:Hydrogels; D004008:Diclofenac; D002351:Carrageenan; D048271:Chitosan; C035736:glutaric acid; D005976:Glutaral