How do you prepare ceftriaxone for a rat?

How do you prepare ceftriaxone for a rat? - briefly

Dissolve the required amount of ceftriaxone powder in sterile 0.9 % saline to reach the desired concentration (often 10 mg/mL), filter through a 0.22 µm membrane, and calculate the dose based on the rat’s weight (typically 50–100 mg/kg). Administer the solution by intraperitoneal injection with a sterile syringe, observing precise volume and aseptic technique.

How do you prepare ceftriaxone for a rat? - in detail

To formulate a ceftriaxone suspension suitable for a laboratory rat, follow these precise steps.

1. Calculate the required dose

   • Determine the target dosage in mg/kg (commonly 50–100 mg/kg).
   • Multiply the animal’s body weight (g) by the dose, then divide by 1,000 to obtain the amount in milligrams.
   • Example: a 250 g rat receiving 75 mg/kg requires 18.75 mg of ceftriaxone.

2. Select the appropriate formulation

   • Use sterile powder for injection (e.g., 250 mg vials).
   • Choose a diluent compatible with intraperitoneal or subcutaneous injection, such as sterile 0.9 % sodium chloride or sterile water for injection.

3. Reconstitute the powder

   • Aseptically add the calculated volume of diluent to achieve a concentration that permits accurate dosing with a small injection volume (≤0.2 mL).
   • For the example dose, dissolve 18.75 mg in 0.2 mL, yielding a concentration of 93.75 mg/mL. Adjust volumes proportionally for different doses.

4. Ensure solution clarity and sterility

   • Vortex briefly to dissolve the powder completely; avoid visible particles.
   • Filter the solution through a 0.22 µm sterile syringe filter if any turbidity is observed.
   • Keep the preparation under a laminar flow hood or within a biosafety cabinet.

5. Label and document

   • Record concentration, preparation date, expiration time, and batch number.
   • Mark the syringe with the calculated dose and animal identifier.

6. Administer the injection

   • Warm the syringe to room temperature to prevent vasoconstriction.
   • Use a 27‑30 G needle for intraperitoneal injection; inject the calculated volume slowly to avoid distress.
   • Observe the animal for at least 10 minutes post‑injection for adverse reactions.

7. Storage and stability

   • Use the prepared solution immediately; if storage is required, keep at 2–8 °C and discard after 24 hours.
   • Do not freeze; repeated freeze‑thaw cycles degrade the antibiotic.

8. Safety precautions

   • Wear gloves, lab coat, and eye protection throughout the procedure.
   • Dispose of needles and contaminated materials in approved sharps containers.
   • Follow institutional biosafety guidelines for handling antibiotics.