Permeability and Absorption
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Permeability and Absorption

Permeability refers to the rate at which a compound passes through a biological barrier. Since compounds must pass through biomembranes to reach intracellular therapeutic targets, permeability is extremely important in the drug discovery phase. Drug absorption is the movement of drugs into the blood. The physical and chemical properties, formulation and administration route of drugs will affect the drug absorption process. Therefore, drug absorption evaluation is crucial for studying ADME of new drugs. BOC Sciences is committed to providing comprehensive in vitro permeability services for many years to accurately predict the in vivo absorption efficiency of candidate compounds.

Permeability and Absorption

The transmembrane permeability of drug molecules affects their absorption and distribution in vivo. Because the permeability of compounds across cell membranes is a key feature that determines the rate and extent of human absorption and ultimately affects the bioavailability of candidate drugs. Poorly permeable compounds can lead to poor absorption (for oral drugs) or poor systemic distribution, thereby affecting the ADME profile of the drug. Theoretically, drugs can cross cell membranes by passive diffusion, facilitated passive diffusion, active transport, and pinocytosis. The physicochemical properties of the drug, such as drug molecular size and lipophilicity, as well as membrane-based efflux mechanisms can contribute to variability in permeability.

Skin absorption occurs when drug effector molecules pass through the skin and enter the body. Skin absorption is a route of administration for the treatment of skin-related diseases. Scientifically assessing the skin absorption level helps to improve drug efficiency and safety, and reduce the pharmacological damage of compounds to the skin. BOC Sciences has established standard skin absorption test standard to evaluate the in vitro skin penetration data for active ingredients. We use layered thicknesses of human or animal skin as models for static and flow-through diffusion for skin penetration testing.

Parallel Artificial Membrane Permeability Assay (PAMPA) provides a high-throughput, non-cell-based method for predicting passive, transcellular intestinal absorption, the process by which most small molecule drugs enter the circulation. In the PAMPA method, an artificial membrane immobilized on a filter is placed between the donor and acceptor chambers. Compounds are introduced into the donor chamber. Following the infiltration period, the amount of compound in the donor and acceptor compartments was quantified using scanning UV spectrophotometry. BOC Sciences offers comprehensive in vitro PAMPA testing services to accurately predict the in vivo oral absorption efficiency of your compounds.

Caco-2 cells are derived from human colon carcinoma and have typical features of intestinal epithelial cells. Caco-2 cells are widely used in the development of new drugs and the study of intestinal drug absorption mechanism. Therefore, measurement of Caco-2 cell permeability not only helps to determine intestinal permeability but also identifies specific transporters or efflux proteins as well as intestinal phase II drug metabolizing enzymes. BOC Sciences has established a Caco-2 cell permeability measurement program based on industry standards to evaluate epithelial and endothelial permeability and intestinal absorption efficiency.

In addition to Caco-2 cell permeability, MDCK cell permeability test is another assay widely used to screen the permeability of compounds. MDCK cells grow and differentiate faster than Caco-2 cells. Therefore, it provides an attractive alternative to Caco-2 cells to assess the intestinal barrier in humans. The MDCK permeability assay helps to understand the mechanism of compound efflux and helps to identify drug permeability-related issues in the early development stages.

Membrane drug transporters have been identified as determinants of drug absorption in vivo, which may affect pharmacokinetics, drug interactions and safety. Drug transporters are expressed in various tissues including brain, intestine, kidney and liver. Given that most drugs are developed for oral administration, in vitro permeability and transporter assays have become key tools for assessing the potential in vivo absorption properties of drugs. BOC Sciences provides the detection of various transporters, including but not limited to P-gp, BCRP, BSEP, OAT1, OAT3, OATP1B1, OATP1B3, OCT1 and OCT2.

If you are interested in our permeability and absorption testing services, please contact us for more information.