| STUDY |
Each of the respective copolymers (having various concentration ratios of TA:SA) were also tested for mutagenicity and cytotoxicity using the forward mutation assay involving Salmonella typhimurium using 8-azaguanine resistance as a genetic marker [Skopec et al, Proc. Natl. Aca. Sci. USA 75:410-414 (1978)]. This mutagenicity assay also includes a test for toxicity so that the mutagenicity, if present, can be expressed quantitatively as the number of mutants per surviving cell. In this way, an independent measure of toxicity for the bacterial species can be obtained. Samples of each copolymer were tested at 1 mg/ml levels both with and without the addition of mammaalian metabolism enzymes. The results of this assay demonstrated that the degradation products of each copolymer, regardless of TA:SA ratio concentrations were non-mutagenic, with or without the addition of a mammalian metabolizing system. Similarly, there was no toxicity in any sample without the addition of metabolic enzymes, and there was a slight, but not significant toxicity in samples with the metabolizing system
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