Modified ionic gelation method preparation of hydrogel microbeads of a water soluble drug

Abstract

Ionic gelation method has been one of the most popular and industrially feasible techniques of microfabrication of drugs and biotechnological products avoiding harsh condition when compared with other encapsulation techniques like solvent evaporation. One of the major limitations for this versatile technique for preparation of hydrogel microstructures is the low encapsulation efficiency for water soluble drugs because they leach out to curing solution during encapsulation and hardening. Although some measures like reducing curing time, low stirring speed, higher gel strength etc. were suggested in previous studies. The present research proposes and examines an alternative approach of modified ionic gelation method for encapsulation of water soluble drug, metformin hydrochloride in this study, through modifying drug solubility in curing solution by using mixed solvents. Varying concentrations of calcium chloride into aqueous acetone were employed at a fixed stirring speed of 150 rpm in RBF for preparation on microbeads. A combined pre-gelatinized Bora rice-Sodium alginate gel matrix backbone, previously blended with drug and ultrasonicated, was used as matrixing material for encapsulation. The prepared beads, washed with acetone and dried in a rotary vacuum drier and subsequently in hot air oven below 40°C were evaluated on the basis Drug Entrapment Efficiency.