Injectable biomaterials biocompatibility testing

The two most important areas of research when developing an injectable biomaterial for potential human use are (1) material characterization and (2) biocompatibility testing. Material characterization requires extensive rheological testing to assess a material s delivery performance and mechanical stability. The following lists summarize the general material characterization tests required by the FDA. 

The IDE submission is the cmcial hurdle and major milestone that transitions a promising material into a viable and testworthy medical device. The IDE s format is a testament to this transformation. The first half of the submission is a detailed report of the injectable biomaterial s evolution and optimization -including all background data and all reports of prior investigation. This section includes the history of the material, all current mechanical and chemical testing, in vitro and in vivo modeling, and biocompatibility results. The second half of the submission, however, focuses on the injectable biomaterial as a device. This... 

The extract dilution type of cell culture assay requires a solvent extraction of the biomaterial under consideration and testing of this extract, most commonly at various dilutions, for evidence of cytotoxicity and cellular interaction. This type of cell culture assay finds its most common use in providing information for regulatory compliance. As identified in the preceding Materials for Medical Devices section and in Table 1, low-molecular-weight extractables are of concern regarding biocompatibility. The extraction assay, carried out with a series of solvents that are hydrophilic and hydrophobic, permits examination of the potential cytotoxicity of extracts and the identification of materials within a biomaterial that may be cytotoxic. These types of assays ultimately permit identification and characterization of cytotoxic materials within biomaterials or the lack of cytotoxicity, as well as providing correlation with in vivo assays such as sensitization, irritation, intracutaneous (intradermal) reactivity, and other tests where the in vivo injection of extracts is required. 

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