Depilated skin areas

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. 

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. 

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. 

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. 

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