National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/IMM90006-01abs

Abstract from Report IMM90006 on Polydimethylsiloxane

The Assessment of Contact Hypersensitivity to Polydimethylsiloxane in Female B6C3F1 Mice (CAS No. 9016-00-6 or 63394-02-5)

The following abstract presents results of a study conducted by a contract laboratory for the National Toxicology Program. The findings have not been peer reviewed and were not evaluated in accordance with the levels of evidence criteria established by NTP in March 2009. The findings and conclusions for this study should not be construed to represent the views of the NTP or the U.S. Government.


Introduction

Polydimethylsiloxane polymers are used in surgical procedures such as implants for plastic surgery, as components for catheters, to encase electrode and pacemaker leads, and in prostheses. Reports on the sensitizing potential of silicone are controversial and incomplete, particularly pertaining to its action as an irritant and inducer of inflammation. The objective of this study was to determine the sensitizing potential of polydimethylsiloxane fluid by the dermal route in mice.

Design

Polydimethylsiloxane fluid was obtained from Surgitech Natural Y Surgical Specialties (Paso Robles, CA). No lot analysis was provided by the supplier. Primary irritancy studies indicated that the material was not an irritant at any concentration tested, including undiluted. Groups of female B6C3F1 mice were sensitized dermally to neat polydimethylsiloxane daily for 5 consecutive days and challenged 7 days later with undiluted polydimethylsiloxane. Exposure details are given in the Figure legends. A 0.5% solution of 1-fluoro-2,4-dinitrobenzene(Sigma Chemical Co.; Lot number 88F-3832; > 99.0% pure as determined by high performance liquid chromatography), was used as a positive control. The irritancy response was determined by monitoring extravasation of 125I-bovine serum albumin into the treated area. The contact hypersensitivity response was determined by monitoring the infiltration of 125I-iododeoxyuridine labeled cells into the challenge site and the Mouse Ear Swelling Test.

Results

There were no treatment-related effects on survival or body weights. No statistically significant hypersensitivity response was observed in mice sensitized with polydimethylsiloxane fluid using either the radioisotopic method, or the MEST.

Conclusion

Under these experimental conditions, no statistically significant irritancy or contact hypersensitivity responses were observed in mice exposed dermally to polydimethylsiloxane.


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