Parylene N, C meets the biological testing requirements of ISO-10993 and has passed the certification tests for Class VI plastics in the United States Pharmacopeia, including cytotoxicity, sensitization, intradermal irritation, acute systemic toxicity, and implantation (requiring 1, 12, and 26 weeks for C); For N and HT, 1 and 12 weeks are required, as well as blood solubility tests. In vitro tissue culture studies have shown that human cell types are prone to proliferation on surfaces coated with Parylene C. Parylene N and C have been proven to comply with USP Class VI (Biological Testing Requirements for UDP Class VI Plastics).