InvivoPharm is a preclinical contract research organisation (CRO) providing services in the general areas of drug-receptor occupancy, radiolabeled drug distribution and autoradiography.

Quantitative Whole-Body Autoradiography Service

Whole-body autoradiography produces an image of the distribution of a radiolabeled test drug over the entire animal.  Whole-body autoradiography is useful for determination of the following drug distribution parameters:

• Sites of accumulation or retention of the drug, including small organs and individual tissues

• Ability to cross blood-brain and placental barriers or penetrate tumors

• Guiding toxicology studies

• Potential of radiopharmaceuticals for PET / SPECT imaging and organ dosimetry

• Routes of elimination

In Vitro Autoradiography Service

In vitro autoradiography images the distribution of radioactivity in the brain or other target organ following incubation of cryostat-cut tissue sections in a radioactive drug.  It can be used for determining the distribution and density of drug receptors in the tissue sections.  It can also be used for competition-type assays, where the IC₅₀ for a non-radioactive test drug to displace the receptor-binding of a standard radiotracer to various regions-of-interest in the sections is determined.

In Vivo Receptor Occupancy

Measures the degree to which the test drug actually occupies its receptor in vivo. Receptor occupancy is determined by measuring the ability of a systemic dose of the test drug (non-radioactive) to compete with binding of a radiolabeled drug to the receptor in vivo.  Useful to determine the dose or plasma concentration of the test drug needed to reach a therapeutically effective occupancy level.

In Vitro Receptor Occupancy: Radioligand Binding Assay

Radioligand (competitive) binding assays determine the IC₅₀ and K_i value for receptor-drug interactions in a tissue homogenate by measuring the ability of the (non-radioactive) test drug to compete with binding of a radiolabeled drug to the receptor.   Hot saturation assays using the radiolabeled ligand alone can be used to determine the density (B_max) of the receptor in the tissue.