PERCUTANEOUS ABSORPTION OF TRICLOSAN 211 o o

212 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS thus the observed penetration was equivalent to 5.57 gg cm -2. Adjustment for an 81.3•o excretion of a known dose given subcutaneously, gives a corrected penetration figure of 6.85 [tg cm -2. Application of [alii Triclosan in ethanol It was difficult to spray a standard dose of aerosol deodorant on to rat skin. Thus, ethanol, which is one of the main ingredients of the aerosol formulation, was used as a solvent in which to apply a more accurately known amount of [all] Triclosan to experimental animals. The results of the penetration studies from ethanol are recorded in Tables V and VI. Of the [all] Triclosan applied to skin, a high proportion was recovered from the patch lint or in the treated skin area. It can be seen (Table V) that in some instances the treated skin contains the larger amount of [all] Triclosan, while in other cases the patch lint contains the greater proportion. The level of tritium in the blood calculated as ppm Triclosan (i.e. gg ml -•) rises to a maximum at about 6 h after application and falls steadily thereafter. Based on the recovery of tritium in the urine and faeces during the first 48 h of the experiment (Table VI) the equivalent of 36.3+5.88 gg [all] Table V. Penetration of Triclosan from ethanol Time after Tritium in application Residue ([tg) in blood Rat (h) Patch Skin (7.5 cm 2) (as ppm Triclosan) 1 1 21.06 ! 63.63 O. 294 2 138.98 27.56 0.070 3 2 14.73 166.73 O. 194 4 21.04 167.50 0.362 5 4 128.16 27.65 0.114 6 133.67 23.85 0.190 7 6 93.08 38.48 0.301 8 112.32 29.96 0.228 9 24 81.26 25.75 0.241 10 48 79.36 21.84 0.119 I l 96 69.84 17.74 0.072 12 63.43 16.33 0.074 To 7.5 cm 2 clipped dorsal female rat skin was applied 0.2 ml ethanol containing 162 [tg [•H] Triclosan. The alcohol was allowed to dry and the skin protected with a non- occlusive patch. The rats were placed in individual metabolism cages, killed and the patch, treated skin and blood, urine and faeces were collected separately every 24 h and analysed for tritium.