Drugs testing, using animals tissues

The CVM accepts many AOAC and equivalent methods for use by laboratories in testing for drug residues in animal tissues. The CVM has adopted the consumption estimates used by the FAO/WHO Joint Expert Committee on Food Additives in the development of standards for drug residues in animal tissues. 

Only after all these exhaustive tests are a few candidates selected for pre-clinical in vivo studies using animal disease models. The current approach is to perform as many tests as possible based on tissue cultures or cell-based assays, as they are less costly and provide results more readily. At the end of this long process is the availability of selected drug candidates with sufficient efficacy and safety required for human chnical trials. 

Applying metabonomics involves generating metabolic databases for control animals and humans, diseased patients, and animals used in drug testing, and the simultaneous acquisition of multiple biochemical parameters on biological samples. Metabonomics is usually conducted with biofluids, many of which can be obtained noninvasively (urine) or relatively easily (blood), but other more exotic fluids such as cerebrospinal fluid, bile, seminal fluid, cell culture supernatants, tissue extracts, and similar preparations can also be used to determine the metabolites present, both in homeostasis and when the organism has been affected by factors such as environmental exposures. 

The intended use of analytical methods in general and screening tests in particular, not only determine FDA s regulatory capabilities, but also determine the extent and complexity of the performance evaluation of the method. For example, in practice rapid screening tests can be used to assay animal tissues or fluids for specific drugs which are known to be present in the animal or to test animal tissue or fluids for the presence of drugs which may be present in the animal. 

Acute toxicity studies in two animal species are required by the FDA for all new drugs prior to their use in humans. Subacute and chronic toxicity studies are required for drugs that are intended for chronic systemic use. Toxicity testing in animals usually involves the determination of lethal dose, monitoring of blood, hepatic, renal, and respiratory functions, gross and histopathologic examination of tissues, and tests of reproductive effects and potential carcinogenicity. 

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