Combination of coating and injectable hydrogel depot to improve the sustained delivery of insulin

Abstract

In this study, a sustained insulin delivery system was developed and evaluated with the combination of coating and injectable thermosensitive hydrogel depot. Poloxamer 407 (P407) and poloxamer 188 (P188) was employed as main materials and sodium alginate (SA) and hydroxypropyl methyl cellulose (HPMC) were incorporated to increase hydrogel strength. Insulin microcrystal was coated in a fluidized bed coater with a 2% (v/v)ethylcellulose (EC) solution. The hydrogels were characterized by scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). The gelation temperature and gelation time, syringeability and swelling were measured. Furthermore, the in vivo pharmacodynamic studies and muscular irritation were also evaluated. The results demonstrated that the hydrogels were biocompatible and combination of hydrogels with coated insulin microcrystal had optimum sustained release property for insulin.