Tissue Distribution Assay
Creative Animodel offers tissue distribution assay, the in vivo experimental compounds distribution assay for our global clients. We can help you design your study and select the appropriate model to meet the project needs. Total drug quantitive levels in different tissues and high-resolution images of the spatial distribution are provided by our expertized scientists with the perfect technology platforms.
Drugs carried in the bloodstream will penetrate those tissues which they can, net transfer being down the concentration gradient. That process is called tissue distribution, and a number of drugs have been studied in detail with regard to tissue distribution. The objective of tissue distribution studies was first to determine which tissues showed selective uptake, in the hope of discovering sites of action, and second to aid the understanding of the time course of both the drug in the body and pharmacological effect. Tissue Distribution Studies of the one-time type were time-consuming, and they have largely been superseded by such techniques as microdialysis, and by imaging methods such as whole body autoradiography and positron emission tomography (PET). In the process of drug development, drug delivery effects can be determined by tissue distribution experiments, which can be used to improve the advantages of drugs in delivery.
Figure 1. Different concentration of drug in tissues. (Matabudul D et al. 2012)
Approaches Provided for Tissue Distribution Studies
In this approach, the radioactively labeled substance under investigation is administered to test animals, which are killed at suitable time intervals, and frozen sections of tissues or of the whole body prepared. An image of the radiation is obtained by placing the sections next to a photographic emulsion. Thus, if a whole body section is used, and the radioactivity is specifically localized in highly perfused organs such as the lungs and liver, the image will reveal this. Comparison with a normal photograph of the slice is used to identify which tissues contain the radioactivity. Densitometry can be used to quantify the relative amounts of radioactivity. This technique has been used to show highly-specific localization of endogenous materials, such as iodine in the thyroid gland, and cholecystokinin in the walls of the stomach and intestine. Less specific but no less valuable information is obtained with drugs.
Positron Emission Tomography (PET)
Synthetic radioactive isotopes (e.g. 11C, 13N, 15O and 18F) with atomic masses less than the naturally occurring stable isotopes have half-life values of 2–110 minutes and emit positrons that interact with electrons to emit gamma radiation that can be detected outside the body. The isotopes are generated in a cyclotron and incorporated into the drug molecules immediately before the administration of the drug. PET scanning permits the production of images of live organisms including humans.
Figure 2. Example of PET/CT acquisitions showing effects on biodistribution of 18F-FHBG.
Creative Animodel is a leading company specialized in new drug screening, including ADME and pharmacokinetics. Our perfect technology platforms and expertized technicians both guarantee the result's reliability and veracity. If you have any questions, please do not hesitate to contact us. Looking forward to cooperating with you.
Matabudul D.; et al. Tissue distribution of (Lipocurc™) liposomal curcumin and tetrahydro curcumin following two-and eight-hour infusions in Beagle dogs. Anticancer Research. 2012, 32(10): 4359-4364.