Permeability Assay Services

Permeability assays can enable accurate predictions of in vivo bioavailability, and are crucial for classification of drugs based on Biological Classification System. Leveraging these studies properly can inform development and streamline regulatory applications. 

Absorption Systems offers two assays types to investigate intestinal permeability:




We also perform tissue-based studies. These models can be used in early-stage preclinical studies to compare different formulations of your drug or can be used post-marketing to evaluate new formulations and determine the feasibility of various dose routes.

The Absorption Systems Difference

Absorption Systems have over 20 years experience in providing state-of-the-art permeability assays, from early-stage compound screens to optimization protocols. The Absorption Systems philosophy is, wherever possible, to use the same rigorously validated test systems throughout the drug development continuum. 


What are the advantages of cell monolayers?

Established, robust in-vitro models, Regulatory acceptance as a tool for predicting intestinal absorption, cell lines express several different uptake and efflux transporters proteins critical in predicting DDIs, cheaper test than excised tissue permeation allows for informed decisions before expensive testing.

The fixed protocols and rapid turnaround time make them ideal for screening large numbers of compounds early in drug discovery. At a later stage, when the same tests are run as custom assays, including test conditions optimized for a given compound, additional bioanalytical rigor, etc., you can count on getting the same results.


How are different cell lines used in cell-based assays?

Different cell lines (e.g., Caco-2 clone C2BBe1, MDR1-MDCK, MDCK, BCRP-MDCK) are used as in vitro models for different purposes. Caco-2 cell monolayers predict not only intestinal absorption but also drug-drug interactions involving transporters. Likewise, MDR1-MDCK cell monolayers are used to predict drug-drug interactions involving the efflux transporter P-glycoprotein as well as blood-brain barrier (BBB) penetration. Other ExpressPlus™ assays utilizing the same test format identify substrates and inhibitors of transporters.

Transporters expressed in Caco-2 cell lines


What are the advantages of tissue-based assays?

More complex drug permeability and metabolism questions can be answered with unique, tissue-based models. Absorption Systems has expertise in conducting tissue-based intestinal permeability studies in different species such as human, rat, dogs, and monkeys. For example, our scientists are experts in the usage of tools such as the Ussing Chamber for intestinal permeation. 


Can permeability assays ease regulatory approvals?

Permeability assays can have wide ranging importance for NDA, ANDA and other regulatory applications. In particular, permeability classification of solid, orally-dosed drugs may allow for a biowaiver that can limit the need for expensive clinical evidence of bioequivalence. 

To find out how permeability assays could assist in your regulatory approval process, get in touch.


IDAS2TM extends permeability assays to understand the impact of dissolution

Alongside cell-based and tissue-based assays above, Absorption Systems have developed a novel technology to understand how dissolution impacts permeabiluty in vitro. Visit our dedicated In Vitro Dissolution Absorption System (IDAS) page to find out more.

Connect With Us

Visit Our Online Marketplace
Express Permeability Services Available for Easy Online Ordering

Contact Us To Begin Study
Work with our dedicated Account Management Team to build your custom study