Measure drug:membrane permeabilities with Fluorosome®-trans-ent using the Fluorosome® Solution FS-1 instrument.

• custom designed, dedicated spectrofluorimeter for Fluorosome® related assays
• Small footprint
• Pipette with optical event marker
• Stirred, thermostatted sample compartment
• Disposable cuvettes
• Intuitive FS1.4 software and Toshiba laptop computer

Fluorosomes-trans® are unilamellar bilayer vesicles containing fluorophores within their aqueous interior. Test molecules are added to an aqueous suspension of Fluorosomes® and, as molecules enter or pass through the bilayer, they quench the fluorescence signal. The rate of quenching is related to the membrane permeability of the compound. The new form Fluorosome®-trans-ent was developed to mimic intestinal membranes.

Validation

We chose 25 marketed drugs for which we could obtain reliable human oral absorption data from the literature, NOT oral bioavailability.
We measured membrane flux rate constants for the drugs in triplicate in the FS-1 at 25 oC in “H buffer” at pH 7.4.
Rate constants were converted to permeabilities with FS1.4 software.
Drugs and results are tabulated in the following table.

The above graph shows that the Fluorosome® Permeability Coefficient has a very good correlation with the human oral absorption of the drugs tested except for one drug and has no false negatives for highly absorbed (>90%) drugs.