How to administer drops into a rat’s nose? - briefly
Gently restrain the rat, tilt its head back, and apply the measured volume of liquid to the nostril using a calibrated pipette; if necessary, use light anesthesia to reduce stress. Observe the animal until the drops are absorbed and no leakage occurs.
How to administer drops into a rat’s nose? - in detail
Administering liquid formulations to the nasal cavity of a laboratory rat requires precise technique to ensure accurate dosing and minimize distress. The following protocol outlines equipment, preparation, handling, and delivery steps.
Equipment and Materials
- Microliter syringe (e.g., 10‑30 µL capacity) equipped with a blunt‑tip, 30‑gauge needle
- Sterile, isotonic vehicle (saline, PBS, or formulation buffer)
- Anesthetic system (isoflurane vaporizer or injectable agent such as ketamine/xylazine)
- Heating pad or warming platform
- Absorbent pad and disinfectant wipes
- Personal protective equipment (gloves, lab coat, eye protection)
Pre‑procedure Preparation
- Verify dose volume; typical nasal instillation in rats ranges from 5 µL to 10 µL per nostril.
- Load the exact volume into the syringe, avoiding air bubbles.
- Pre‑warm the rat on a heating pad for 5 minutes to reduce hypothermia risk.
- Induce anesthesia to a surgical plane; confirm lack of reflexes before proceeding.
Animal Positioning
- Place the anesthetized rat in a supine position on a soft, non‑slipping surface.
- Gently extend the neck by supporting the head with a fingertip, creating a slight upward tilt of the snout.
Instillation Technique
- Hold the syringe at a shallow angle (approximately 30°) relative to the nasal plane.
- Position the needle tip just outside the nares, avoiding contact with the mucosa.
- Slowly dispense the predetermined volume; the droplet will be drawn into the nasal cavity by capillary action.
- After delivery, keep the head elevated for 10–15 seconds to allow absorption and prevent immediate drainage.
Post‑procedure Care
- Maintain the rat on a warming pad until full recovery of righting reflex.
- Observe for signs of respiratory distress, epistaxis, or abnormal behavior for at least 30 minutes.
- Record the administered dose, animal identifier, and any adverse observations.
Troubleshooting Tips
- If the droplet does not enter the nostril, adjust the angle or gently massage the external nares to open the passage.
- Excessive leakage indicates over‑volume; reduce the dose in subsequent trials.
- Repeated attempts on the same animal increase stress; consider a new subject if the first attempt fails.
Adhering to these steps provides reproducible nasal delivery while maintaining animal welfare and experimental integrity.