Absorption of BLANKOPHOR BHC from a detergent solution applied to the skin of pigs

Abstract

The dermal absorption of BLANKOPHOR BHC, a fluorescent whitening agent (FWA), was studied in three pigs. A 0·02% solution of [ 14C]BLANKOPHOR BHC in a 0·5%, detergent solution was applied under occlusion to a skin area of approximately 500 cm 2 on each pig for 10 hr. Absorption of tritiated water, determined in parallel on the same animals, showed the rate of water absorption through the skin to be l·4 mg cm −2 hr −1. This is very close to the rate of water absorption determined in human skin. so that the results of BLANKOPHOR BHC absorption obtained on the skin of pigs can be extrapolated to human skin. The maximum rate of absorption of 14C activity, expressed as BLANKOPHOR BHC, was 1·6 ng cm −2 hr −1, compared with the 1·4 mg cm −2 hr −1 for water absorption under the same conditions. Maximum absorption per hour was 0·02% of the dermally applied dose of BLANKOPHOR BHC. At the end of the 10-hr period of exposure under occlusion, the levels of 14C activity in the organs and tissues of the pigs ranged from 0·l to l·3 ppb. In the skin. the FWA showed a high affinity for the stratum corneum. Autoradiographic and radiometric studies indicated that delayed absorption of the FWA remaining on or in the skin at the end of the 10-hr period would be negligible or non-existent.