Toxicity testing of urinary catheters.

The tissue toxicity of 23 urinary catheter batches (6 latex and 2 non-latex brands) was tested in vitro and in vivo. In vitro, a human T-cell leukemia line (JM) was cultured in the presence of different concentrations of eluates made from the catheters. The cytotoxicity of the eluates was assessed from their ability to inhibit DNA synthesis measured by incorporation of 3H-thymidine. In vivo, two methods were used. Strips of catheters were implanted into the rabbit dorsal muscle and pieces of catheters were implanted into the rat peritoneal cavity. After four days, the foreign body reaction, type of inflammation and necrosis were quantified macroscopically and by light microscopy. The results of the in vitro cytotoxicity test were correlated with those of in vivo methods. The rat peritoneal implantation test correlated better with the cell culture test (P less than 0.01) than with the rabbit muscle implantation test (P less than 0.05). Based on the clinical experience of urethral stricture complications caused by urinary catheters, catheters yielding eluate which at 30% dilution inhibited 50% DNA synthesis were regarded as toxic. According to this, the rabbit muscle implantation test was not reliable in testing the tissue toxicity of urinary catheters, while the cell culture test was quantitative and seemed to correlate with both the rat peritoneal implantation test and with the clinical complications observed.