BDDCS - Biopharmaceutical Drug Disposition Classification System

BDDCS (Biopharmaceutical Drug Disposition and Classification System) divides compounds into four classes based on their permeability and solubility. This classification system is useful in predicting effects of efflux and uptake transporters on oral absorption as well as on postabsorption systemic levels following oral and intravenous dosing.

Click on the class to see the selection of assays.

Class 1 (High solubility, high permeability):

The high permeability/high solubility of such compounds allows high concentrations in the gut to saturate any transporter, both efflux and absorptive. Class 1 compounds may be substrates for both uptake and efflux transporters in vitro in cellular systems, but transporter effects on absorption will not be important clinically.

Efflux transporters may have, however measurable effect on the penetration of the compounds through the blood-brain barrier. If the systemic concentration of the compounds is lower, transporters may overcome the effect of the high passive permeability of the compound.

These compounds can also be involved in transporter mediated drug-drug interactions.

Available assays for efflux transporters and blood-brain barrier penetration:

Class 2 (Low solubility, high permeability) :

These high permeability compounds will pass through the gut membranes and uptake transporters will have no effect on absorption. However, the low solubility will limit the concentration at the enterocytes, thereby preventing saturation of the efflux transporters. Consequently, efflux transporters will affect the extent of oral bioavailability and the rate of absorption of Class 2 compounds.

Available assays:

Class 3 (High solubility, low permeability):

For Class 3 compounds, the drug availability will be sufficient in the gut lumen due to good solubility, but an uptake transporter will be necessary to overcome the poor permeability of these compounds. Apical efflux transporters may also be important for the absorption of such compounds when sufficient penetration is achieved via an uptake transporter.

Available assays:

Class 4 (Low solubility, low permeability):

Due to the low permeability and low solubility of these compounds both uptake and efflux transporters play an important role in the oral bioavailability of Class 4 compounds.

Available assays: