Development of Cross-Linked Alginate Beads by Ionotropic Gelation Technique for Controlled Release of Diclofenac Sodium

The aim of the study was to formulate colon targeted diclofenac sodium alginate beads. The beads were formulated by ionotropic gelation using sodium alginate as polymer, calcium carbonate as an internal cross linking agent and calcium chloride as an external cross linking agent. The optimized beads contained Neusilin and coated with Eudragit L100. The beads were analyzed in terms of, encapsulation efficiency (EE%), particle size and morphology. Swelling properties were studied in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.4). In vitro drug release was studied in SGF, pH 1.2, SIF, pH 6.8 and SIF, pH 7.4. The results show that the particle size of the beads ranged from 1.98 ± 0.40 to 2.80 ± 0.30 mm. The optimized batch containing Neusilin® had the highest EE% of 72 % significantly higher than other batches (p < 0.05). The degree of swelling of the beads was zero in SGF and about 90 % in SIF at 100 min. The results of the in vitro release showed that the beads had 0 % release in SGF, pH, 1.2 at 2 h, about 3 % in SIF, pH 6.8 at 4 h and 9 % drug release in SIF, pH 7.4 at 9 h. Therefore, sodium alginate beads could be used for colon delivery of diclofenac sodium.