The experiment mimics acute permeability after an IV injection. Plasma vs. brain levels are compared, and the "P" value is calculated. The values are compared with those for known permeant or non-permeant compounds. A simultaneous injection of 14C sucrose or 3H-theophylline is usually employed.
The results are compared to published "P" values for a variety of compounds.
The compounds are injected intra-luminally, and concentrations are detected intra-/extra-luminally for 60 min. at 5–10 min. intervals.
The experiment evaluates if low permeability detected in Short-term Exclusion Assessment is due to active extrusion or poor octanol-water partition.
The compounds (three observations per compound) are injected extra-luminally, and concentrations detected intra-/extra-luminally for 60 min. at 5–10 min. intervals.
If requested, the experiments can be repeated in the presence of putative extrusion (e.g., PgP) blockers for the same fee.
The experiment evaluates whether the low permeability detected in the Short-term Exclusion Assessment is due to active extrusion or poor octanol-water partition.
The experimental design mimics an "IV drip" with constant plasma concentrations for 24–48 h.
The compounds (three observations per compound) are injected intra-luminally, and the concentrations are detected intra-/extra-luminally at 1–2 h intervals for up to 2 days.
If requested, the experiments may be repeated in the presence of putative extrusion (e.g., PgP) blockers for the same fee.
The experiment analyzes the effects of a given compound on blood-brain barrier integrity.
Trans-endothelial electrical resistance (TEER) or sucrose are measured.