Graphical representation of in vitro cyto-compatibility of delivery systems depicted by percent relative cell viability after 24, 48 and 72 h at different dilutions of copolymer degradation products extracted by incubating copolymer formulation (A) without chitosan for 10 days at 37 °C, (B) with chitosan for 10 days at 37 °C, (C) without chitosan for 10 days at 70 °C, and (D) with chitosan for 10 days at 70 °C. Biocompatibility was evaluated in HEK-293 cell line using MTT assay. Data expressed as mean ± SD, n = 4.