RISK ASSESSMENT OF DITHIOCARBAMATE ACCELERATOR RESIDUES IN LATEX-BASED MEDICAL DEVICES - GENOTOXICITY CONSIDERATIONS

The Medical Devices Agency (MDA) has investigated potential human heal th hazards arising from the presence of dithiocarbamate vulcanization accelerators in latex products (mainly gloves). After collection of ma nufacturer's data on usage acid residues of these accelerators, an ind ependent investigation of solvent extractable residues and dithiocarba mate migration into aqueous simulants was commissioned, to complement equivalent ''in-house'' test data from two major manufacturers. The pr esence of extractable accelerator residues in commercial products was confirmed. Potential human health hazards associated with dithiocarbam ates include genotoxicity and possible carcinogenicity: a review of pu blished data was conducted to evaluate the evidence for this, with par ticular reference to three zinc dithiocarbamates with significant comm ercial usage (ZDMC, ZDEC and ZDBC: see Fig. 1). Data gaps were identif ied, and mutagenicity studies commissioned to fill these. These studie s comprised tests both in vitro (bacterial and L5178Y cell gene mutati on, cultured lymphocyte chromosome aberration) and in vivo (mouse bone marrow micronucleus, rat liver UDS). It is concluded that ZDMC must b e considered a genotoxin (and thus a probable carcinogen): residues of this substance in latex medical devices should be minimized. ZDEC pro ved genotoxic in vitro but was not clearly genotoxic in vivo, and may have activity intermediate between that of ZDMC and that of ZDBC, whic h showed at most weak activity in a single in vitro (chromosome aberra tion) test. It is proposed that the use of ZDBC as a vulcanization acc elerator in the manufacture of latex gloves, rather than ZDEC, ZDMC or their precursors, would reduce or remove the health concerns arising from accelerator residues. Crown Copyright (C) 1998 Published by Elsev ier Science Ltd. All rights reserved.