Depilated skin

Albino guinea pigs are treated at a depilated skin area for about 3 weeks with the drug substance. After that period, animals are irradiated with UV-A and UV-B at a level which causes a weak erythema only. After that a 2 weeks latency period follows without any treatment. Thereafter animals are irradiated again with UV-A and UV-B at a dose level not causing erythema. 

Acute dermal reactions to 90Sr have been described for depilated skin in mice, guinea pigs, and pigs. In mice, skin exposed to a single 2,000-5,000 rad (20-50 Gy) dose of beta radiation from a 90Sr-90Y source... 

Application of chlordane in alcohol at 273 mg/kg/day or in cottonseed oil at 217 or 222 mg/kg/day for 1-4 days to depilated skin of rats did not result in tremors (Ambrose et al. 1953a). "Early production chlordane" induced tremors, convulsions, and seizures in rabbits to which 780 mg/kg was applied to the skin (Ingle 1965). Fringe and O Tousa (1950) also noted tremors, convulsions, and seizures in mice treated topically with "early" production chlordane. These effects were observed at 7.4 and 29.6 mg chlordane/kg/day in mice treated 5 days/week for 20 weeks. Data generated with "early" production chlordane are not used to estimate levels of significant exposure. 

GD Goat Percutaneous 0.177 0.137 0.248 4.905 Depilated skin. Deaths within 48 hours 60... 

Radioactivity was detected in the blood and urine of a single female dog, 1 hour after dermal application of a 2.094-g dose of TOCP labeled with radioactive phosphorus to a 300-cm2 area of clipped and depilated abdominal skin (Hodge and Sterner 1943). Gas chromatographic analysis of blood detected no parent material in male rats at 4, 24, or 48 hours after a 24-hour, occluded exposure to a hydraulic fluid containing 99.9% cyclotriphosphazene, but the presence of metabolites in the blood was not investigated (Kinkead and Bashe 1987). 

Twenty-four hours after application of 2.094 g TOCP labeled with radioactive phosphorus to a 15x20 cm area of clipped and depilated abdominal skin, radioactivity was detected in the following tissues in a dog, listed in order of decreasing concentration (counts per gram of tissue) skin and facia at site of application, liver, omental fat, blood, kidney, lung, muscle (triceps femoris), spinal cord, heart, spleen = brain = sciatic nerve, and bone (femur) (Hodge and Sterner 1943). 

Leather is a very complex and heterogeneous substrate. Once the animal has been slaughtered, the hide or skin has to be removed, cleaned, depilated, and tanned in the so-called beam house process. The term hide is used for the outer covering of animals with a body surface area of more than 1 m2 like bovines, and the term skin for that of smaller animals like sheep, goats, and pigs. Large proportions of sheepskins are used for fur production. 

For dermal toxicity testing the drug substance is applied by innunction of a certain volume onto a depilated (mechanically or by depilatories) skin areas. However, these methods can alter the permeability of the skin. In order to avoid licking off from the treated skin areas, Elizabethan collars can be fixed around the neck of the animals. 

Albino guinea pigs or albino mice are depilated. The test compound is administered to the hairless skin in a concentration which does not cause skin irritation. Two hours after administration irradiation is performed in a dose which does not cause skin inflammation (erythema, oedema). The spectrum of the UV light should cover a wave length pattern of both UV-A and UV-B, i.e. in the range of 280-320 nm and 320-400 nm. 

DNOC is generally not irritating to the skin of animals. No signs of local irritation or evidence of systemic toxicity were observed after 1.8% DNOC as the sodium salt was applied daily to the depilated dorsal surface of 10 rats or 6 rabbits for 30 days (Ambrose 1942). However, slight skin irritation was observed only on the abdomen after DNOC was applied to both the abdomen and the ears of rabbits daily, for 1 -7 days or for 5 days/week for 4 weeks (Spencer et al. 1948). 

Toxicity. Mineral oils produce slight-to-moderate irritation by standard rabbit skin irritation tests (Beck et al., 1982 Mayhew et al., 1985). Repeated applications of mineral oils to skin over a week resulted in epidermal hyperplasia, hyperkeratosis, and depilation C14-C19 hydrocarbons caused more damage than C21-C23 hydrocarbons (Hoekstra and Phillips, 1963). 

Another popular depilatory is the wax-type product. This depilatory is applied as a viscous liquid over the hair area to be removed. It is often warmed under the tap prior to application and applied in the direction of hair growth. The wax is sometimes covered with a paper cloth, oftentimes supplied with the product. The cloth adheres to the sticky wax composition on the skin and is pulled in the direction against the hair growth removing much of the sticky wax and the hair. This procedure is repeated until the desired area is depilated. The residual wax is then washed and peeled from the skin. 

See also MI, Folder 2B, Exhibit RCL/75, PTP 215, A Comparison between Depilated and Clipped Skin on the Percutaneous Toxicity of Nerve Gases to Rabbits , c. January 1951, pp. 126-34. 

Hair removers are designed to remove hair from the skin surface without cutting in order to avoid undesirable stubble. Cosmetic products have been developed for chemical destruction of hair, that is, depilation, and for facilitating mechanical hair removal, that is, epilation. 

A. Muir and S. Callaway, Comparison between depilated and clipped skin in the percutaneous toxicity of nerve gases to rabbits, PTP 215, UK Archive Number WO 189/561,1950. 

Chandrasekaran, S., Dhar, S. C. Studies on the development of a multiple proteinases concentrate and its application in the depilation of skins. Leather Sci 1985, 32,297-304. 

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