Psoriaskill is being developed for marketing as a topical psoriasis (a skin disorder characterized by peeling, scaling and itching) agent by Oceans of Potions Ltd. To gain FDA approval, Psoriaskill must be tested for skin sensitivity. A consulting company (Svengalilabs Research Institute) is hired to run the skin sensitivity test.
TEST DESIGN
• 90 female rats, 6 months old (equivalent of late teens, early 20s, and concerned about their skin) were selected for the experiment. The rats were divided into 6 dose groups of 100% (F), 50% (E), 25% (D), 10% (C) and 1% (B) of pure Psoriaskill, as well as a control diluent (mineral oil, A).
• A 4 cm by 4 cm patch of each rats’ back was shaved of fur with an electric rotary razor (after the long fur was trimmed) once per week. Psoriaskill, at either one of the 5 test concentrations or the mineral oil diluent was applied to the entire shaved area at a rate of 5 ml/rat/day for 6 days/week. There was not an application of the potion on the day of shaving (the 7th day).
• Applications continued in the above manner for 10 months. The rats were maintained and observed for an additional 10 months (so a total of 20 months for the experiment). Rats were monitored two times/day (at 10:00 am and at 4:00 pm). General comments about food and water consumption, body weight, consistency of waste and overall appearance were noted. No significant changes were noted between dose groups. No rats were deleted from this study.
• At the end of the 20-month period, the rats were carefully observed. All Type 1A skin growths were counted (the data sheet is attached). Note: Type 1A skin growths are hypothetical lesions for purposes of this assignment, not real lesions.