National Toxicology Program

National Toxicology Program

Abstract from Report IMM89037 on o-Benzyl-P-Chlorophenol

Report on the Assessment of Contact Hypersensitivity to O-Benzyl-P-Chlorophenol in Female B6C3F1 Mice (CAS No. 120-32-1)

Report Date: February 1990

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 The findings have not been peer reviewed and were not evaluated in accordance with the levels of evidence criteria established by NTP in March 2009.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.


O-benzyl-p-chlorophenol (OBPC) was selected for evaluation as a sensitizing agent for contact hypersensitivity in mice. O-benzyl-p-chlorophenol is used as a disinfectant and a germicide.

The objective of this study was to determine the sensitizing potential of o-benzyl-p-chlorophenol when applied dermally to female B6C3F1 mice.

O-benzyl-p-chlorophenol was tested on female B6C3F1 mice. The doses of o-benzyl-p-chlorophenol ranged from 3.0% to 10% in one part olive oil in four parts acetone for sensitization and 20% for challenge. Mice received 20 ┬Ál by direct dermal application for 5 consecutive days to a prepared site. DNFB (1-fluoro-2,4-dinitrobenzene) (99.6%, Sigma Chemical Co.) was used as a positive control at a concentration of 0.5%. Measurement of the contact hypersensitivity was accomplished by the radioisotopic assay and the mouse ear swelling test (MEST).

A statistically significant dose-dependent contact hypersensitivity response to o-benzyl-p-chlorophenol was demonstrated in mice when the site of sensitization was prepared using shaving and dermabrasion with or without adjuvant.

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