RESIDUAL ACCELERATOR AND CYTOTOXICITY OF NR GLOVES: A NOVEL APPROACH TOWARDS SAFER NATURAL RUBBER GLOVES

Abstract

The global share of natural rubber gloves versus synthetic gloves is steadily declining in the last 10 years from 80 % to less than 50%. This has been attributed to three critical drawbacks namely Protein Allergy due to inherent proteins in NR gloves, Chemical allergy due to residual accelerator chemicals in gloves and the glove powder issue. The present work is an attempt to reduce the residual accelerator in NR gloves by practical and effective offline leaching of the gloves. Our studies have shown that the commercial NR gloves in Indian market contain very high level of residual accelerators ranging from 800 to 2800 micrograms per gram of the glove sample. The total residual accelerator present in six commercial brands available in Indian market was estimated using UV-Visible Spectroscopy. HPLC studies have shown that the major accelerator used in all the glove brands was the zinc diethyl dithiocarbamate (ZDEC). The quantification by UV analysis showed that the total residual accelerators varied from 926 to 2725 µg per gram of the glove. The quantification of the specific ZDEC peak by HPLC revealed that ZDEC content varied from 873 to 2616 µg per gram of the glove among the surgical gloves. More than 14% of the total residual accelerator in glove leached into sweat equivalent aqueous extracts. The cytotoxicity studies of the aqueous extract of the glove brand against L-929 cell line using MTT assay revealed severe toxicity with less than 20 per cent cell viability at various dilutions. The direct contact assay of the glove sample showed severe cytotoxicity of grade 4. The aqueous extracts have been shown to possess very high cytotoxicity against cell lines. A proprietary offline leaching method was developed at RRII by which more than 90 to 95% of the total residual accelerator in the glove samples could be removed. The novel method requires 30 to 90 seconds of leaching time. The advantage of the new method lies in the fact that it can be easily integrated with the online leaching process currently employed for the glove manufacturing in future. The study also shows that the mechanical properties of the glove are well preserved after the leaching process, which again reveals that the leaching process is not harsh.