MediGel® Sucralose is an Efficient Method of Acetaminophen Delivery for Rats to Reduce Pain

Good animal welfare is at the basis of good science. Animal distress is against ethical values that all scientists should adhere to. Moreover, if an animal is in pain, it could affect research experiments and production, resulting in delayed timelines and difficulties in interpreting results. In order to provide a framework and guidelines to humane use of animals in scientific research, the principle of the 3Rs were developed back in 1959:

• Replace – Substitute animal experimentation by another method when possible


• Reduce – Use as few animals as possible to get relevant results


• Refine – Keep the animals in good health, minimize pain and distress

Reducing Pain in Research Setting

All methods that minimize the pain, suffering, distress or lasting harm that may be experienced by research animals, and which improve their welfare, are a requirement to comply with the USDA Animal Welfare Act and the U.S. National Research Council Guide for Care and Use of Laboratory Animals. Analgesics that are orally self-administered by an animal have a dual impact: they reduce the pain due to surgery or health condition, while at the same time eliminating the distress of handling and disruption caused by painful injections. Routes of oral administration include feed, water and gel and research is needed to evaluate consumption and efficiency.

It is with this objective in mind that Laura Riddle, DVM, MPH and her group at the US Army Institute of Surgical Research in Texas collaborated with Nicole Rowley, DVM, MPH and her group at the Uniformed Services University of the Health Sciences in Maryland. Together, they evaluated the ingestion of acetaminophen in water and MediGel® Sucralose by Sprague Dawley rats after laparotomy, after a study was published in mice in 2014 (Christy et al. JAALAS 2014 ). 

Acetaminophen Delivery in MediGel® Sucralose for Rats

The concentration of acetaminophen in the water and gel was 2 mg/mL to achieve a targeted dose of 200 mg/kg, which falls within the therapeutic range for rats. Water bottles and gel cups were weighed, and the amount of water and/or gel ingested in mL per rat was then multiplied by the acetaminophen concentration in the water or gel to obtain a total amount of acetaminophen ingested per animal.



Delivery system for acetaminophen was consumed equally as well among the three treatment groups (AW = water, AG = MediGel® Sucralose, AWG = water+ MediGel® Sucralose), and all groups exceeded the targeted therapeutic dose of 200 mg/kg, showing that MediGel® Sucralose is an efficient method of acetaminophen delivery for rats to reduce pain.

For more information, see the poster presented at the 70^th AALAS National Meeting in Denver, Colorado. To try MediGel® Sucralose first hand, request a sample!