Preparation of injectable sodium alginate/ poloxamer composite hydrogel for sustained drug release

Abstract

Poloxamer is a thermo-sensitive synthetic polymer that can achieve sol-gel transition with temperature change, but its relative molecular mass is low, and the hydrogel structure is difficult to maintain for a long time. The thermo-sensitive sodium alginate/poloxamer composite hydrogel (SA/P407) was synthesized by mixing poloxamer with sodium alginate. The chemical structures, temperature sensitivity, microscopic morphology, dynamic viscoelasticity and in vitro drug release behaviors of sodium alginate/poloxamer composite hydrogels were investigated by FT-IR, test tube inversion, SEM, rheometer and UV-Vis spectroscopy. In addition, the swelling properties of sodium alginate/poloxamer composite hydrogels were also studied. These results show that the sodium alginate/poloxamer composite hydrogel is thermo-sensitive, and the gelation concentration (mass fraction is 6%) of poloxamer at body temperature can be reduced by adding sodium alginate. By controlling the mass ratio of sodium alginate and poloxamer, the sol-gel transition temperature can be kept between room temperature and body temperature (25-37 ℃), and the gelation time can be shortened to 84 s. The sodium alginate/poloxamer composite hydrogel has a structural feature of high porosity and interconnected pores, and its pore size ranges from 20 μm to 80 μm. With the increase of sodium alginate, the swelling rate of the sodium alginate/poloxamer composite hydrogel is gradually decreased. The sodium alginate/poloxamer composite hydrogel shows sustained release of the anticancer drug gemcitabine, and the drug release time can reach 72 hours. Sodium alginate/poloxamer composite hydrogel has an important application prospect in the field of injectable carriers for sustained drug release.

Keywords

• sodium alginate
• poloxamer
• sol-gel transition
• sustained drug release