The search for better antibiotics for treating captive animals
By Allison Tonini
What do African lions, American alligators, Amur tigers and grizzly bears all have in common? Besides being a bit toothy, all are wild animals that often need medication when they are housed in captivity. And with a roster that exotic, administering medication is no easy task for veterinarians. Animal caretakers are constantly searching for effective and durable treatments for animals in captivity.
To help them in their quest, researchers used Morris Animal Foundation funding to test cefovecin, a promising antibiotic that is used to treat certain types of bacterial infections in companion animals. The drug (which is commercially sold as Convenia) is known for its longacting duration in certain species. After just one injection, cefovecin stays in the bloodstream of dogs and cats for as long as two weeks. Cefovecin’s durability is theorized to be, in part, directly correlated to a species’ protein-binding level; the higher the species’ protein-binding level, the longer the duration of cefovecin in the bloodstream and the better it will work.
Dr. Bonnie Raphael and Dr. Marc Valitutto, both of the Wildlife Conservation Society, recently completed a study that tested the protein-binding levels of cefovecin in different species.
“We’re always looking for long-lasting antibiotics, so we don’t have to handle animals as often,” says lead investigator Dr. Raphael.
Their aim was primarily to find out which species had high protein-binding levels and, therefore, would benefit from a further pharmacokinetic study with cefovecin.
Pharmacokinetics is the process of how a drug is absorbed, distributed, metabolized and excreted in the body. A full pharmacokinetic study on cefovecin in individual species would provide an accurate evaluation of how the drug should be effectively administered to a specific species.
“Since we can’t test every different antibiotic in every different animal, we’re trying to find out which species would benefit most from an individual pharmacokinetic study,” she says.
The study findings supported the researchers’ hypothesis that high protein binding is an indicator for cefovecin’s long-lasting properties. Both researchers concluded that all avian and reptile species showed poor protein-binding levels and should not be considered for further testing. Several species, including animals of the order Carnivora (e.g., large cats, bears, raccoons), hoofstock (e.g., okapi, deer), marine mammals and swine, showed high protein-binding levels and therefore should be considered for additional pharmacokinetic studies.
Because of cefovecin’s complexity, the researchers are confident that their efforts are a step in the right direction for the accurate use of the antibiotic.
“Knowing the protein-binding level gets us a lot closer to what we’re trying for,” says Dr. Raphael. “We’re saving a lot of research time.”
And when asked how they handle giving an antibiotic to a grizzly bear?
“With some difficulty,” Dr. Raphael replies with a laugh.
Posted by MAFon February 23, 2012. Permalink