1. Field of the Invention
The instant invention relates to apparatus for and methods of collecting urine from laboratory animals, and more particularly, the instant invention relates to apparatus for and methods of collecting urine from laboratory rodents in accordance with structures and procedures which prevent the urine from being contaminated by other substances present in the environment of the laboratory rodents.
2. Technical Considerations and Prior Art
In conducting experiments utilizing animals, it is frequently necessary to collect urine from the animals for analysis. For example, it is necessary to analyze the animal's urine when conducting bioavailability studies to determine if a drug ingested by a laboratory animal is absorbed, and when conducting toxicity studies to determine if there is any change in pH, excreted electrolites, etc. Moreover, is is frequently necessary to quantitatively collect and separate urine containing pharmaceuticals and their metabolites from fecal pharmaceuticals and metabolites and/or contaminants. Rats and mice are the primary laboratory animals utilized for bioavailability and toxicity studies. Since rats and mice are relatively small animals, collecting their urine while not drastically interfering with other body functions, such as their freedom of movement, has been a difficult task. The general approach is to simply place the animals in a cage with a screen floor which serves, in essence, as a filter that stops the animal's feces while allowing urine to flow through by gravity for collection in a container beneath the cage. This method is not entirely satisfactory because the urine can become contaminated as it flows over the feces or can become contaminated by food and food particles which drop on and through the screen. When testing pharmaceuticals in small rodents, the pharmaceuticals are normally administered via the food so that any food which is dropped on the screen floor by the animal can contaminate the animal's urine with unconsumed pharmaceutical as the urine washes over the food. This would indicate that a portion of the pharmaceutical had been adsorbed into the animal's body from ingestion of the food when, in fact, it had not. None of the procedures proposed or practiced prior to the instant invention prevents this contamination. Moreover, the urine collectors currently utilized have metal in direct contact with the animal which may lead to undesirable oxidation of urinary pharmaceuticals and metabolites.