Question 1

What are the main advantages of oral dosing through drinking water or food?

Accepted Answer

Oral dosing via water or food is non-invasive, administers the compound continuously, and mimics human oral drug administration. However, it lacks precision because compound intake depends on animal acceptance of food or water, compound stability, and the number of animals in the cage. This method is best for animal welfare when exact dosing is not critical.

Question 2

How does oral gavage differ from other oral administration methods?

Accepted Answer

Oral gavage deposits the compound directly into the stomach at a specific time and volume, providing precise dosing unlike water or food methods. However, it requires proper training because improper technique can cause serious damage to the animal. The procedure must be performed on conscious animals with intact swallowing reflexes to prevent accidental placement into the trachea.

Question 3

What needle specifications are needed for oral gavage in mice versus rats?

Accepted Answer

For mice, use 20-25 gauge straight or curved dosing needles that are 1.5 inches long. For rats, select 18-20 gauge straight or curved dosing needles that are 2-3 inches long. Needle gauge and syringe selection also depend on the volume and viscosity of the compound being administered.

Question 4

What is the proper restraint technique for performing oral gavage in mice?

Accepted Answer

Grasp the skin at the base of the head and hold the scruff tightly to minimize side-to-side head movement. Suspend the body in a straight line from head to tail, and stabilize the hindquarters to prevent body rotation. Proper handling and restraining techniques are critical because any twisting impedes needle placement into the esophagus.

Question 5

What factors determine the absorption of topical agents applied to animal skin?

Accepted Answer

Topical agent absorption depends on skin condition, surface area utilized, substance concentration, duration of contact, and the lipid solubility of the agent. Topical agents are typically intended to affect only the applied area, but they can be absorbed into the bloodstream either intentionally or unintentionally depending on these factors.

Question 6

What preparation steps are required before applying a topical compound to an anesthetized animal?

Accepted Answer

First, anesthetize the animal using a fast-acting inhalant for quick recovery. Remove all fur from the application area using a hair clipper with its flat surface against the skin, shaving opposite to hair growth direction. Clean the skin with water and dry it with gauze. Apply several thin layers of the substance using a cotton-tipped applicator for best results.

Question 7

How should animals be managed after topical compound application to prevent ingestion?

Accepted Answer

Place a small collar or shield on the animal to prevent it from reaching the affected body part and ingesting the topically applied compound through grooming. Additionally, house treated animals individually to prevent allogrooming from cage mates, which could transfer the compound to other animals or cause unintended exposure.

ניהול מתחם II - חידון הערכה