Alginate-sterculia gum gel-coated oil-entrapped alginate beads for gastroretentive risperidone delivery

Novel floating-mucoadhesive oil-entrapped alginate beads coated with crossslinked alginate-sterculia gum gel membrane was developed for gastroretentive risperidone delivery. Oil-entrapped alginate beads containing risperidone as core were prepared by ionotropic gelation technique. Effects of polymer to drug ratio and oil to water ratio on drug entrapment efficiency (%) and cumulative drug release after 8 h (%) were studied to optimize the core beads by a 32 factorial design. The optimized beads (F-O) demonstrated drug entrapment efficiency of 83.73 +/- 0.81% and cumulative drug release of 70.84 +/- 0.27% after 8 h. The biopolymeric-coated optimized beads exhibited excellent buoyancy, better ex vivo mucoadhesion and slower drug release rate. The drug release profiles of risperidone-loaded uncoated and coated beads were best fitted in Korsmeyer-Peppas model with Fickian diffusion mechanism. The beads were also examined for the drug-excipients compatibility, drug crystallinity and surface morphology by FTIR, P-XRD and SEM analyses, respectively. (C) 2014 Elsevier Ltd. All rights reserved.