Environmental Conditions of the Test Facilities

The investigation room was kept at a temperature range of 19°C-25°C and humidity range of 30% to 70% (Weil 2007, p. 177). However, during the process of cleaning the room, the humidity was kept at a range of 50% to 60%. On the other hand, the animals were supplied with artificial lighting in which 12 hours of darkness and 12 hours of light were allowed (OECD 1998c; OECD 1998b).

Animal Caring and Feeding

The animals were supplied with specified diets and a regular supply of water. In addition, the food given to the rats was changed every seven days at a temperature of 2-8°C (OECD 1998b, p. 4).

Dose levels

The animals were dosed on the basis of their group numbers as follows:

1. Group 1: Vehicle
2. Group 2: Low dosage levels
3. Group 3: Medium dosage levels
4. Group 4: High dosage levels
5. Group 5: high dosage levels with a 14 day recovery period
6. Group 6: Vehicle and high dosage levels for toxicokinetic studies (OECD 1998a)

In addition, dosing of the test item was done on a daily basis for 28 days. The highest dose as specified by the sponsor was 600 mg/ kg of body weight per day. Moreover, dosing was done at the same time each day.

Experimental Evaluation

Observations

Observations were made for a period of 28 days during which time the rats were left without any treatment for 14 days. This is important because it enables the analyst to evaluate the possibility of the rats recuperating from the toxic effects of the test item (Webster 2005, p. 185). In addition, general clinical observations were conducted once per day to examine the climax stages of the anticipated outcomes after dosing. On the other hand, a general health observation was conducted twice per day to assess any cases of mortality and morbidity. Most importantly, a major clinical examination was conducted on all animals before the first exposure and once per week after exposure (OECD 1998a).

Measurement of Changes

Any major observable changes in the skin, fur, eyes, mucous membranes, the presence of excretions and secretions, and other autonomic activities were recorded on a daily basis. In addition, any changes in posture, gait, response, the presence of tonic movements, and bizarre manners were also recorded. On the other hand, the rate of water consumption and changes in the body weight were measured on a weekly basis