Carboxymethyl fenugreek galactomannan-gellan gum-calcium silicate composite beads for glimepiride delivery

Novel carboxymethyl fenugreek galactomannan (CFG)-gellan gum (GG)-calcium silicate (CS) composite beads were developed for controlled glimepiride (GLI) delivery. CFG having degree of carboxymethylation of 0.71 was synthesized and characterized by FTIR, DSC and XRD analyses. Subsequently, GLI-loaded hybrids were accomplished by ionotropic gelation technique employing Ca+2/Zn+2/Al+3 ions as cross-linkers. All the formulations demonstrated excellent drug encapsulation efficiency (DEE, 48-97%) and sustained drug release behaviour (Q8h, 62-94%). These quality attributes were remarkably influenced by polymer-blend (GG:CFG) ratios, cross-linker types and CS inclusion. The drug release profile of the optimized formulation (F-6) was best fitted in zero-order model with anomalous diffusion driven mechanism. It also conferred excellent ex vivo mucoadhesive property and considerable hypoglycemic effect in streptozotocin-induced diabetic rats. Furthermore, the beads were characterized for drug-excipients compatibility, drug crystallinity, thermal behaviour and surface morphology. Thus, the developed hybrid matrices are appropriate for controlled delivery of GLI for Type 2 diabetes management.