Biocompatibility of injectable chitosan–phospholipid implant systems

Injectable biomaterials are desirable therapeutic platforms due to minimal invasiveness and improved patient compliance, and are applicable in such areas as compound delivery and tissue engineering. The present work examined the biocompatibility of injectable blends composed of chitosan, phospholipid and lauric aldehyde (PoLigel-LA) or lauric chloride (PoLigel-LCl). In vitro cytotoxicity was evaluated in L929 and HeLa cell lines. Both blends resulted in acceptable biocompatibility, although greater cell viability was seen with PoLigel-LA. In vivo biocompatibility was investigated in healthy CD-1 mice. Subcutaneous injection of the PoLigel-LA blend caused no local or systemic toxicities over a four-week period while the PoLigel-LCl caused immediate local toxicity. Mice injected intraperitoneally with PoLigel-LA did not show physical or behavioural alterations, and body weight changes did not differ from control animals. Furthermore, histological examination of spleen and liver showed unaltered morphology. Interleukin-6 levels in mice injected with PoLigel-LA did not differ from levels of control animals (6.91 ± 3.61 pg/mL versus 6.92 ± 5.02 pg/mL, respectively). Biodegradation occurred progressively, with 7.4 ± 5.02% of the original injected mass remaining after four weeks. Results obtained herein establish the biocompatibility of PoLigel-LA and indicate its potential for use in various localized therapeutic applications.