How much prednisolone should be given to a rat? - briefly
The typical experimental dose of prednisolone for a rat is about 2 mg kg⁻¹ of body weight, administered orally or subcutaneously, with a generally accepted range of 1–5 mg kg⁻¹. Adjust the exact amount according to the study protocol and relevant ethical guidelines.
How much prednisolone should be given to a rat? - in detail
The dose of prednisolone for a laboratory rat is expressed as milligrams per kilogram of body weight (mg kg⁻¹). Published pharmacological studies and veterinary guidelines converge on a therapeutic range of 0.5–5 mg kg⁻¹ per day, depending on the experimental purpose, route of administration, and duration of treatment.
- Weight calculation – Determine the animal’s mass (average adult rat: 250–300 g). Convert to kilograms (0.25–0.30 kg) before applying the dose formula.
- Dose selection –
– Low‑dose anti‑inflammatory protocols: 0.5–1 mg kg⁻¹ day⁻¹.
– Immunosuppressive or disease‑model studies: 2–5 mg kg⁻¹ day⁻¹.
– Acute high‑dose experiments: up to 10 mg kg⁻¹ for a single injection, followed by a taper. - Route of administration –
– Oral gavage: dissolve prednisolone in a suitable vehicle (e.g., 0.5 % methylcellulose).
– Intraperitoneal injection: dissolve in sterile saline or phosphate‑buffered solution; ensure complete solubility to avoid precipitation.
– Subcutaneous injection: use a sterile aqueous solution; limit volume to ≤0.2 mL per 100 g body weight. - Frequency – Once‑daily dosing is standard for steady‑state plasma concentrations. Split dosing (e.g., 12‑hour intervals) may be required for high‑dose regimens to reduce peak‑related toxicity.
- Preparation – Prednisolone sodium phosphate is preferred for injectable forms due to higher solubility. Adjust pH to 7.0–7.4 to minimize tissue irritation.
- Monitoring – Record body weight, food intake, and clinical signs daily. Obtain blood samples at 24‑hour intervals to measure plasma cortisol suppression, confirming pharmacodynamic effect. Watch for signs of immunosuppression, hyperglycemia, or gastrointestinal ulceration, especially at doses ≥5 mg kg⁻¹.
- Safety limits – Acute toxicity in rats has been reported at doses >50 mg kg⁻¹. Chronic administration above 10 mg kg⁻¹ may cause adrenal atrophy and severe metabolic disturbances.
Example calculation for a 280‑g rat using a moderate immunosuppressive dose of 3 mg kg⁻¹:
- Convert weight: 0.280 kg.
- Multiply by dose: 0.280 kg × 3 mg kg⁻¹ = 0.84 mg prednisolone per day.
- Prepare a 1 mg mL⁻¹ solution; administer 0.84 mL orally or 0.84 mL intraperitoneally (adjust volume according to route limits).
Adhering to these parameters ensures reproducible pharmacological effects while minimizing adverse outcomes in rodent studies.