JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Pharmacy IV EXPERIMENTAL PHARMACOLOGY Previous Question Paper (July/August-2022 - R17)

Blood collection from laboratory animals is a critical procedure in experimental pharmacology requiring adherence to ethical guidelines (3Rs: Replacement, Reduction, Refinement). The choice of technique depends on the required volume, frequency of sampling, and the species.

Common Techniques:

• Tail Vein/Artery (Rat/Mouse): Involves warming the tail to dilate vessels. Advantage: Easy access for repeated sampling. Limitation: Risk of tissue necrosis or hematoma if performed incorrectly.
• Retro-orbital Sinus: Blood is collected from the venous sinus behind the eye using a capillary tube. Advantage: Allows rapid collection of relatively large volumes. Limitation: Highly invasive, requires anesthesia, and carries risks of ocular damage.
• Saphenous Vein: Blood is collected from the lateral saphenous vein on the hind leg. Advantage: Less stressful, does not require anesthesia, and allows repeated sampling. Limitation: Technically challenging and yields smaller volumes.
• Cardiac Puncture: Performed via thoracic approach. Advantage: Yields maximum blood volume. Limitation: Terminal procedure (must be performed under deep anesthesia/euthanasia), high risk of pericardial hemorrhage.
• Jugular Vein Catheterization: Surgical placement of a catheter. Advantage: Ideal for serial sampling in conscious animals. Limitation: Requires surgical skill and maintenance to prevent infection or thrombosis.

Maximum Blood Withdrawal Limits:

The total blood volume of a healthy laboratory animal is approximately 6-7% of its body weight (60-70 mL/kg). As a general rule, no more than 10% of the total blood volume should be withdrawn in a single session, and no more than 15% in a 24-hour period. For repeated sampling, a recovery period of 2-4 weeks is typically required to allow for erythropoiesis.

Euthanasia is the act of inducing humane death in laboratory animals with minimal pain, distress, anxiety, and fear. It involves the use of pharmacological or physical methods that rapidly produce loss of consciousness followed by cardiac or respiratory arrest and the ultimate loss of brain function.

The common routes of drug administration in laboratory animals, along with their typical maximum volumes and limitations, are summarized below:

When selecting a route, the physical state of the animal, the volume of the substance, and the required speed of onset must be strictly considered to ensure animal welfare and experimental validity.