Studies on release kinetics of curcumin from alginate dialdehyde hydrogel

Hydrogels are 3D cross-linked polymer matrix used as drug delivery system. Alginate dialdehyde (ADA) was prepared by oxidizing sodium alginate and cross linked as hydrogel using gelatin as cross-linking molecule for controlled release of curcumin. Two formulations of alginate hydrogel and curcumin loaded alginate hydrogel (in situ loading and soaking method) were prepared. The hydrogels were evaluated for gelling time, swelling measurements, fluid uptake ability and evaporation rate. FTIR and SEM image analysis were conducted. The alginate hydrogel without curcumin showed 184s of gelling time, 1.45 degree of swelling (Q value) and 66.35 % water retention ability. Whereas, curcumin loaded alginate hydrogel had 3.45 degree of swelling (Q value) and 62.52 % water retention ability. The entrapment efficiency of was estimated to be 2.67% and 3.82% respectively for hydrogel loaded with curcumin by in situ and soaking method respectively. From FTIR spectrum, formation of aldehyde group is inferred. SEM image of alginate hydrogel confirmed its porous nature and that of curcumin loaded hydrogel showed the pores filled with curcumin. The alginate hydrogel loaded with curcumin is then studied for curcumin release kinetics by using model dependent approaches. Zero order model of drug release is the best fit model for both in situ and soaking loaded hydrogel with a regression value 0.99 and 0.98 respectively. The anti-oxidant activity of released curcumin was determined as 34.57% and that for native curcumin is 46.59%. This implies that there is no significant modification in the activity of curcumin entrapped in the hydrogel.