Comparative study of the leachability of di(2-ethylhexyl) phthalate and tri(2-ethylhexyl) trimellitate from haemodialysis tubing

The leachability of both Di(2-ethylhexyl) phthalate (DEHP) and Tri(2-ethylh exyl) trimellitate (TEHTM) or Trioctyl trimellitate (TOTM) from haemodialys is tubing was investigated in 20 patients with chronic renal failure underg oing ga maintenance haemodialysis. The blood tubing made of common polyviny l chloride (PVC) plasticized with DEHP (group I patients) were replaced wit h tubing plasticized with TOTM-DEHP (group 2 patients). The patient blood o btained from the inlet and the outlet of the dialyzer was analyzed during a 4 h-dialysis session. Thus, the circulating concentrations of both DEHP an d TOTM resulting from the release from dialyzer tubes were estimated using High-performance Liquid chromatograph (HPLC). With the common PVC-DEHP bloo d tubing, a DEHP quantity of 122.95 +/- 33.94 mg was extracted from tubing during a single dialysis session (ranging from 55 to 166.21 mg). During the same period, the total amounts of DEHP retained by the patients were 27.30 +/- 9.22 mg (ranging from 12.50 to 42.72 mg). As for blood tubing plastici zed with TOTM-DEHP, 41.80 +/- 4.47 mg of DEHP and 75.11 +/- 25.72 mg of TOT M were extracted. During the same period, the amounts of DEHP and TOTM reta ined by the patients were 3.42 +/- 1.37 mg and 4.87 +/- 2.60 mg, respective ly. The extraction rate both plasticizers was correlated with serum lipid c ontent (cholesterol + triglyceride) (r(2) = 0.75 for DEHP and r(2) = 0.64 f or TOTM). In the present investigation, less TOTM and DEHP were apparently released from haemodialysis tubing plasticized with TOTM-DEHP than DEHP rel eased from haemodialysis tubing plasticized with DEHP only. TOTM seems to b e a Superior alternative to DEHP for use in medical devices because of its potential lower leachability. To recommend it as an alternative plasticizer , its possible toxicity towards human body should be investigated before it can be used routinely. However, patients undergoing haemodialysis using tu bing plasticized with DEHP only are regularly exposed to non negligible amo unts of DEHP. In view of several biological effects previously reported, it is time to reconsider the use of DEHP only as a plasticizer. (C) 2001 Publ ished by Elsevier Science BN.