In the central nervous system (CNS) early assessment of compound availability is essential for CNS drugs and useful for optimizing the toxicity profile of non-CNS drugs. Designing pharmaceutical agents so that they pass the blood-brain barrier and are freely available to interact with receptors is one of the great challenges in CNS drug development.
The TRANSIL Brain Absorption assay kit from Sovicell has been developed to help overcome this hurdle. Since the TRANSIL Brain Absorption Kit is a fast high-throughput format assay, it can also be used to assess brain penetration of any non-CNS drug in secondary screening.


TRANSIL Brain Absorption assay plates are ready-to-use. They are delivered with assay buffer and TRANSIL beads with reconstituted porcine brain lipid membranes.
The assay principle consists of simply adding a fixed concentration of compound to the microplate wells with pre-dispensed TRANSIL beads in increasing concentrations (increasing membrane surface area).


Various compounds were selected. The final assay concentration was 50 μM. Sample preparation was done according to the kit description. After incubating for 2 minutes at room temperature, the plate was centrifuged to separate the TRANSIL beads (Sovicell) from the suspension. 100 μL of each supernatant were transferred to a Corning 96 well half-area plate for quantification of the remaining drug concentration in the Mithras reader. Extinction was measured at 240, 260, and 280 nm. The wavelength with the highest signal-to-noise ratio was selected for quantifying the interaction of the test drugs with the TRANSIL beads.


Linear models for predicting the brain tissue binding, brain-to-plasma distribution, brain availability as well as compound classification were used as provided in Sovicell's software. The compound classification chart (fig. 2) shows the classification by rate and extent. It separates drugs that are not available in brain (red triangles) from drugs available in brain (light and dark blue dots). The drugs available in brain have either CNS drug like properties (dark blue dots) or likely to exhibit CNS side effects (light blue dots). The classifier (black line) correctly classified 87% of the training set data.


The TRANSIL Brain Absorption Kit is perfectly suited for screening of drug candidate availability in the CNS in combination with the Berthold Mithras microplate reader.

		Link to Sovicell