Toxicity profile of void polymeric nanoparticles. A) A series of eight pancreatic cancer cell lines were exposed to a 20-fold range of void polymeric nanoparticles (93 – 1852 μg/mL), and viability assays (MTT) were performed at 72 hours. Compared to vehicle treated cells, no cytotoxicity is observed in the cells exposed to polymeric nanoparticles. The error bars represent mean and standard deviations of experiments performed in triplicate. B) In vivo toxicity studies were performed by administration of polymeric nanoparticles (720 mg/kg intra-peritoneal twice weekly, three weeks) to a group of 4 athymic mice, which were weighed at weekly intervals in comparison to control mice (N = 4). No significant differences in body weight were seen; at necropsy, no gross toxicity was evident. The error bars represent mean and standard deviations of experiments performed in triplicate.