How should the drug “Enroxil” be administered to rats? - briefly
Administer Enroxil to rats by oral gavage using a sterile saline suspension at the recommended dose of 5 mg kg⁻¹ once daily, ensuring accurate volume calculation based on each animal’s weight.
How should the drug “Enroxil” be administered to rats? - in detail
Enroxil should be delivered to laboratory rats using a well‑defined protocol that includes selection of the administration route, preparation of the dosing solution, calculation of the dose based on body weight, and adherence to animal welfare standards.
The most common routes are oral gavage, intraperitoneal injection, and subcutaneous injection. Choice of route depends on the study’s pharmacokinetic objectives, the drug’s physicochemical properties, and the required exposure duration.
Oral gavage
- Dissolve or suspend Enroxil in a suitable vehicle (e.g., 0.5 % methylcellulose, 1 % Tween‑80, or sterile water) to achieve a concentration that allows dosing volumes of 10 mL kg⁻¹.
- Verify homogeneity by vortexing or gentle sonication before each administration.
- Administer using a calibrated gavage needle (size 20–22 G for adult rats) to avoid esophageal injury.
- Record the exact volume delivered and the animal’s weight to calculate the mg kg⁻¹ dose.
Intraperitoneal injection
- Prepare a sterile solution of Enroxil in isotonic saline or buffered saline, adjusting pH to 7.2 ± 0.2 to minimize irritation.
- Filter the solution through a 0.22 µm membrane to ensure sterility.
- Inject at a volume of 1–2 mL kg⁻¹ using a 25‑27 G needle, inserting the needle bevel up at a 30–45° angle into the lower right quadrant of the abdomen.
- Observe the animal for signs of distress or peritonitis for at least 30 minutes post‑injection.
Subcutaneous injection
- Formulate Enroxil in a viscous carrier (e.g., 0.5 % carboxymethylcellulose) if prolonged release is desired.
- Use a 26‑28 G needle to inject a volume of 0.5–1 mL kg⁻¹ into the dorsal neck fold.
- Monitor the injection site for erythema or swelling daily.
Dose calculation
- Determine the target dose (e.g., 5 mg kg⁻¹) based on prior toxicology data.
- Measure each rat’s body weight immediately before dosing.
- Compute the required drug amount: dose × weight (kg) = mg of Enroxil.
- Adjust the concentration of the dosing solution so that the calculated volume is within the acceptable range for the selected route.
Animal handling and monitoring
- Acclimate rats to handling for at least 5 days prior to the first dose.
- Perform dosing at a consistent time of day to reduce circadian variation.
- Record clinical observations (behavior, respiration, motor activity) at 0, 30 min, 1 h, and daily thereafter.
- Collect blood samples at predetermined intervals to assess plasma concentrations, using appropriate anticoagulants and storage conditions (e.g., –80 °C).
Quality control
- Validate the analytical method for Enroxil quantification in plasma (e.g., LC‑MS/MS) before the study.
- Include vehicle‑only control groups to differentiate drug‑related effects from procedural stress.
- Maintain a detailed log of solution preparation, filter integrity, and equipment calibration.
Following these steps ensures reproducible exposure of rats to Enroxil, supports accurate pharmacokinetic and toxicological assessments, and complies with institutional animal care guidelines.