Comparative in vitro biocompatibility testing of polycyanoacrylates and poly(D,L-lactide-co-glycolide) using different mouse fibroblast (L929) biocompatibility test models

Comparative in vitro cytotoxicity studies of polyalkylcyanoacrylates (PCA) and poly(D,L-lactide-co-glycolide) (PLGA) were performed. Four PCAs of different alkyl chain lengths and two commercially available PLGAs were assayed in several cell culture models recommended by the International Standard Organization (ISO). Different polymer preparations, two extraction methods evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay and LDH (lactate dehydrogenase) release, two indirect contact methods, for example the agar overlay, and a direct contact method were used. Test procedures included light microscopy, the vital stain neutral red, the MTT assay, based on the cleavage of a yellow tetrazolium salt (MTT) to purple formazan crystals by mitochondrial active cells, LDH release and scanning electron microscopy. All polycyanoacrylates tested showed cytotoxic effects with methylcyanoacrylate being the most toxic compound. Cytotoxic effects and proliferation inhibition decreased with increasing alkyl chain length of the PCAs. PLGA was very well tolerated by the cultured cells in all assays performed. The extraction method evaluated by the MTT assay seems to be the most appropriate method, as it showed a clear graduation of toxicity and allowed an estimation of the 50% inhibitory concentration (IC50) values for all polymers tested. (C) 1997 Elsevier Science B.V.