Acta Pharm. 58 (2008) 75-85
Original research paper
Effect of core and surface cross-linking on the entrapment of metronidazole in pectin beads
ATMARAM P. PAWAR, ANIL R. GADHE, PRABAKARAN VENKATACHALAM, PRAVEEN SHER and KAKASAHEB R. MAHADIK
Department of Pharmaceutics,
Accepted November 28, 2007
The purpose of this study was to improve the entrapment efficiency of the water-soluble drug metronidazole using internal cross-linking agents. Calcium pectinate beads containing metronidazole were prepared by dropping a drug-pectin solution in 1% and 5% (m/V) calcium chloride for surface crosslinked beads. For the core cross-linked beads, calcium carbonate was dispersed in the drug-pectin solution. The beads were characterized by particle size, swelling ratio, SEM, DSC, and in vitro drug release. It was found that the beads obtained by core cross linking produced more drug entrapped beads than the surface cross-linked beads. Beads obtained using 1% (m/V) calcium chloride showed more drug entrapment than those obtained using 5% calcium chloride. The core cross-linking of pectin beads reduced drug loss by about 10-20%. The water lodging capacity of beads depended upon gel strength, which is a function of the internal gelling agent and pectin concentration. Complete drug release was observed within 30-60 min in the acidic dissolution medium. This work has showed that the core cross-linking agent increases the water-soluble drug entrapment of in calcium pectinate beads.
Keywords: ionotropic gelling, core crosslinking agent, calcium carbonate, entrapment, metronidazole, Ca-pectinate beads