Even though direct contact technique was used to screen the cytotoxicity of plastic
parenteral containers according to TIS 531, some difficulties were encountered when samples having bag and bottle forms were found moving in the wells during testing. In order to be able to test all types of containers, agar diffusion technique was applied to evaluate 34 plastic parenteral containers parallel with direct contact technique. The L-929 cultures were grown to monolayer in Eagle’s Minimum Essential Medium (MEM) supplemented with 5% fetal bovine serum (FBS). After incubation, the agar layer (1.5%) supplemented with MEM in 5% FBS and neutral-red stain was added to replace the medium. The samples were cut and placed on the agar layer. After 24–hour exposure, the cell monolayers were observed for cell deaths beneath and surrounding the samples as well as changes in morphology and cell densities. In this study, USP Positive Bioreaction RS were used as positive material control. There were no statistical differences between both techniques (P>0.05). However, the agar diffusion technique was a useful method for screening plastic parenteral containers made from polyethylene, polypropylene, polyvinyl chloride and laminar. Therefore, it could be another useful method to be implemented for the cytotoxicity testing scheme in order to replace the direct contact technique.
http://budgetitc.dmsc.moph.go.th/research/pdf/20159.pdf