Evaluation of Allergic Potential of Rubber Products: Comparison of Sample Preparation Methods for the Testing of Polymeric Medical Devices

Abstract

A round-robin study was organized in the international standardization working group, ISO/TC194/WG8, with the purpose to compare the efficacy of different sample preparation procedures for determining the sensitization potency of polymeric medical devices. Three custom-made rubber samples were supplied to the participating laboratories and tested according to predetermined extraction and test protocols: A, formulated with a high level of mercaptobenzothiazole (MBT); B, formulated with a low level of MBT; and C, formulated with zinc dibutyldithiocarbamate. Extraction protocols included the so-called ISO method that applies physiological saline and/or vegetable oil extraction media without concentration (designated here “simple extraction”) and the so-called Japanese method that applies organic solvent extract (in this study chloroform–acetone mixture) after concentration to the test systems (designated here “exhaustive extraction”). Tests included human patch test, guinea pig maximization test (GPMT), adju...