How should ceftriaxone be prepared for a rat? - briefly
Prepare a solution of ceftriaxone sodium salt in sterile physiological saline at the required concentration (e.g., 100 mg/mL). Administer the dose of 50–100 mg/kg subcutaneously or intraperitoneally, limiting injection volume to ≤0.5 mL per 100 g rat.
How should ceftriaxone be prepared for a rat? - in detail
Ceftriaxone intended for rodent use must be prepared under sterile conditions, with precise dosing and appropriate vehicle. The following procedure outlines each step required to obtain a reliable injectable solution.
- Determine the required dose. Typical studies employ 50–100 mg kg⁻¹ administered intraperitoneally; adjust the amount according to the specific experimental protocol and the animal’s weight (e.g., a 250 g rat receiving 75 mg kg⁻¹ requires 18.75 mg of ceftriaxone).
- Select a suitable diluent. Sterile 0.9 % sodium chloride (normal saline) or sterile water for injection is recommended. Avoid solutions containing calcium or phosphate, as ceftriaxone may precipitate.
- Dissolve the antibiotic. Weigh the calculated amount of ceftriaxone powder using an analytical balance. Transfer the powder to a sterile vial and add the predetermined volume of diluent (commonly 1 mL kg⁻¹ of body weight). Mix gently until the powder is fully dissolved; vortexing may be employed for a brief period.
- Adjust pH if necessary. Ceftriaxone solutions are most stable at pH 7.0–8.0. If the solution appears acidic, add a small volume of sterile 0.1 M sodium hydroxide solution dropwise, monitoring with a calibrated pH meter.
- Perform sterile filtration. Pass the prepared solution through a 0.22 µm syringe filter into a sterile container to remove particulate matter and potential contaminants.
- Aliquot and label. Divide the filtered solution into sterile syringes or vials sized for single‑dose administration. Clearly label each aliquot with concentration, volume, preparation date, and expiration time.
- Store appropriately. Keep the solution at 2–8 °C for up to 24 hours. If longer storage is required, freeze at –20 °C in aliquots; avoid repeated freeze‑thaw cycles.
Administration: inject the calculated volume intraperitoneally using a 25‑ to 27‑gauge needle. Ensure the injection site is cleaned with sterile alcohol before needle insertion. Observe the animal for any immediate adverse reactions.
Documentation: record the batch number of ceftriaxone, the exact weight of each animal, the administered dose, and the time of injection. This information supports reproducibility and regulatory compliance.