Biodegradable oligo(amidoamine/β-amino ester) hydrogels for controlled insulin delivery.

Nguyen, Minh Khanh; Huynh, Cong Truc; Gao, Guang Hui; Kim, Ji Hyun; Huynh, Dai Phu; Chae, Su Young; Lee, Kang Choon; Lee, Doo Sung · Soft Matter · 2011

basic_science · Level V

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Abstract

An injectable biodegradable hydrogel system based on oligo(amidoamine/β-amino ester) (OAAAE) was designed and synthesized for controlled release of insulin under the physiological conditions. OAAAE was prepared in one step <i>via</i> the Michael-addition oligomerization of the secondary amine groups of 4,4-trimethylene dipiperidine (TMDP) with the vinyl groups of 1,8-octylene diacrylamide (ODA) and 1,6-hexane diol diacrylate (HDA). The formed oligomer was characterized by 1H NMR and gel permeation chromatography (GPC). OAAAE in aqueous solution (20 wt%) underwent a gel-sol transition in the pH range of 6.8-7.4. A complex hydrogel was formed when mixing insulin with the oligomer solution followed by increasing pH and temperature. Degradation of the hydrogel, influence of insulin on gel phase and gel strength, <i>in vitro</i> cytotoxicity of OAAAE, <i>in vitro</i> and <i>in vivo</i> release of insulin from the complex hydrogel were investigated. Furthermore, the <i>in vivo</i> release profile of insulin from the complex hydrogel was compared with that from the neutral hydrogel.