Preparation, function, and safety evaluation of a novel degradable dermal filler, the cross‐linked poly‐γ‐glutamic acid hydrogel particles

Abstract

AbstractPoly‐γ‐glutamic acid (PGA) is a naturally degradable hydrophilic linear microbial polymer with moisturizing, immunogenic, cross‐linking, and hydrogel water absorption properties similar to hyaluronic acid, a biomaterial that is commonly used as a dermal filler. To explore the development feasibility of cross‐linked PGA as a novel dermal filler, we studied the local skin response to PGA fillers and the effect of various cross‐linking preparations on the average longevity of dermal injection. Injection site inflammation and the formation of collagen and elastin were also determined. PGA hydrogel particles prepared using 28% PGA and 10% 1,4‐butanediol diglycidyl ether showed optimal filler properties, resistance to moist heat sterilization, and an average filling longevity of 94.7 ± 61.6 days in the dermis of rabbit ears. Local redness and swelling due to filler injection recovered within 14.2 ± 3.6 days. Local tissue necrosis or systemic allergic reactions were not observed, and local collagen formation was promoted. Preliminary results suggested that dermal injection of cross‐linked PGA particles appeared safe and effective, suggesting that cross‐linked PGA particles could be developed as a new hydrogel dermal filler.