How should rats be given prednisolone?

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How should rats be given prednisolone? - briefly
Administer prednisolone to rats by oral gavage, delivering the calculated mg/kg dose in a sterile aqueous vehicle (e.g., 0.5 % methylcellulose) once daily.

How should rats be given prednisolone? - in detail
When delivering prednisolone to laboratory rats, the protocol must address dose calculation, formulation, route of administration, timing, and safety monitoring.
The dose is expressed in milligrams per kilogram of body weight. Typical experimental regimens range from 1 mg kg⁻¹ to 10 mg kg⁻¹, depending on the study objective. Calculate the exact amount for each animal using the most recent weight measurement, then convert the dose to the volume of the prepared suspension or solution based on the concentration of the drug.
Formulation considerations:

Dissolve prednisolone in a suitable vehicle such as 0.5 % carboxymethylcellulose, 0.1 % Tween‑80, or a sterile saline solution with a small amount of ethanol (≤5 % v/v) to improve solubility.
Prepare the solution fresh daily or store aliquots at 4 °C for no longer than 48 h to prevent degradation.
Filter-sterilize the final preparation through a 0.22 µm membrane if an injectable route is used.

Common routes of delivery and associated steps:

Oral gavage

Use a calibrated feeding needle (1–2 mm diameter) appropriate for the animal’s size.
Administer the calculated volume (typically 1–2 mL kg⁻¹) slowly to avoid aspiration.
Position the rat in a supine orientation with the head slightly elevated; advance the needle along the esophageal midline.

Subcutaneous injection

Select a site on the dorsal neck or flank, avoiding hair follicles and major blood vessels.
Inject the required volume (usually ≤0.5 mL) using a 27‑30 G needle.
Observe the injection site for signs of irritation or swelling.

Intraperitoneal injection

Insert a 25‑27 G needle at a shallow angle (≈30°) into the lower right quadrant of the abdomen.
Deliver the dose (≤0.5 mL) steadily; monitor for leakage or peritonitis.

Timing and frequency:

Administer the drug at the same time each day to maintain consistent plasma levels.
For chronic studies, repeat dosing at 24‑hour intervals; for acute experiments, a single dose may suffice.
Record the exact time of each administration in the animal log.

Monitoring and documentation:

Observe rats for changes in behavior, food and water intake, and body weight at least once daily.
Collect blood samples at predetermined intervals to verify plasma prednisolone concentrations if pharmacokinetic data are required.
Document any adverse reactions, such as gastrointestinal distress, immunosuppression signs, or injection site inflammation.

Safety precautions:

Wear gloves and eye protection when handling the steroid and solvents.
Dispose of sharps and contaminated materials according to institutional biosafety guidelines.
Verify that the dosing apparatus is calibrated before each use to prevent dosage errors.

By adhering to these detailed steps, researchers can achieve reliable, reproducible administration of prednisolone to rats while minimizing variability and ensuring animal welfare.