Sustained release of Avastin® from polysaccharides cross-linked hydrogels for ocular drug delivery

Avastin(®) was the first choice drug for the treatment of age related macular degeneration (AMD) and proliferative diabetic retinopathy in clinic. Due to its short half-time in intraocular, it was required repeat administration. In this paper, an in situ injectable polysaccharides cross-linked hydrogel was developed for potential ocular drug delivery of avastin. The polysaccharide cross-linked hydrogel was first synthesized by simple mixing of glycol chitosan and oxidized alginate aqueous solution, and then characterized by scanning electron microscopy (SEM) and rheometer. In vitro degradation test indicated that the degradation rate of hydrogels could be controlled by the varying the content of oxidized alginate in hydrogels. In vitro release study showed that the encapsulated avastin had an initial burst release at early stage (within 4 h) followed by a sustained release manner in period of 3 days. With the increase of oxidized alginate concentration in the hydrogel, the release rate of avastin from hydrogels declined accordingly. Meanwhile, the structure stability of avastin released from hydrogels at specific time intervals did not show apparent changes as compared with native avastin based on the analysis of SDS-polyacrylamide gel electrophoresis (SDS-PAEG). As a result, the developed in situ injectable polysaccharides cross-linked hydrogel with controllable degradation rate and drug release might be a versatile carrier for avastin to apply in ocular drug delivery.