Tamarind seed polysaccharide–gellan mucoadhesive beads for controlled release of metformin HCl

The paper describes the development, optimization and evaluation of tamarind seed polysaccharide (TSP)-blended gellan gum (GG) mucoadhesive beads containing metformin HCl through Ca2+-ion cross-linked ionic gelation for oral drug delivery. Effects of GG to TSP ratio and cross-linker (CaCl2) concentration on the drug encapsulation efficiency (DEE, %), and cumulative drug release after 10 h (R10h, %) of TSP–GG mucoadhesive beads containing metformin HCl were optimized by 32 factorial design. The optimized mucoadhesive beads (F-O) showed DEE of 95.73 ± 4.02%, R10h of 61.22 ± 3.44% and mean diameter of 1.70 ± 0.24 mm.These beads were characterized by SEM and FTIR analyses. The in vitro drug release from these beads showed controlled-release (zero-order) pattern over a period of 10 h.The optimized TSP–GG mucoadhesive beads also exhibited pH-dependent swelling, good mucoadhesivity with biological mucosal membrane and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration.