PAMPA has three key models to support the permeability classification of APIs; Gastrointestinal (GIT) Permeability for oral drugs using the Biopharmaceutical Classification System (BCS), Blood-Brain Barrier Permeability for drugs acting on the Central Nervous System and Skin Permeability for dermal/transdermal penetration potential.
The Parallel Artificial Membrane Permeability Assay (PAMPA) is used to determine passive diffusion across an artificial lipid membrane impregnated onto a porous filter support. Passive diffusion is an important factor in determining absorption of orally administered compounds in the gastrointestinal tract (GIT), penetration of the blood-brain barrier (BBB), as well as general transport across cell membranes. Depending upon the type of lipid and the setup used, the PAMPA assay can be predictive of gastrointestinal tract absorption (PAMPA-GIT), blood-brain barrier permeability (PAMPA-BBB) or transdermal penetration (Skin-PAMPA).
Typically, PAMPA experiments are carried out in the early drug discovery phase to select lead compounds with promising oral bioavailability or brain penetration potential by cost-efficiently ranking candidates within large compound sets. The data generated by PAMPA can be used by medicinal chemists to guide structural modifications of discovery compounds to improve their in vivo characteristics.
A minimal accurately weighable quantity of dry compound (~1 mg) or 150 μL of 10 mM stock DMSO solution is required for this assay.
The apparent permeability coefficient for each compound (Papp) is calculated. Full study report is provided.
PAMPA uses two disposable Pion 96-well plates that are assembled into a “PAMPA sandwich”. The top plate (acceptor plate) contains a porous filter at the bottom of each well which is placed on top of a second, donor plate. The filter is coated with a solution of lipid material to prepare the artificial membrane layer. The test compound solutions are added to pH-adjusted buffer in the wells of the donor plate and acceptor buffer solution is added to each well of the acceptor plate. The acceptor plate is placed on top of the donor plate allowing the donor solution to come into contact with the filter support. The plates are then incubated at room temperature, in a humid environment, for up to 4 hours depending on the assay conditions.
Each donor well can be individually stirred using magnetic stir discs. Analytical standards are prepared for each test compound in order to calculate the permeability. Two compounds of known permeability are run as controls on each plate. The donor and acceptor samples for the test and control compounds are quantified by UV plate reader. The experimental analyte recovery is calculated using both donor and acceptor compartment concentrations and can also be used to determine membrane retention percentage.
Drug ionization and physicochemical profiling
Investigation of the Efficacy of Transdermal Penetration Enhancers Through the Use of Human Skin and a Skin Mimic Artificial Membrane
P-Glycoprotein Deficient Mouse in situ Blood-Brain Barrier Permeability and its Prediction using an in combo PAMPA Model
The permeation of amphoteric drugs through artificial membranes - an in combo absorption model based on paracellular and transmembrane permeability
Coexistence of passive and active carrier-mediated uptake processes in drug transport: a more balanced view
Study on permeability enhancing effect of new ceramide-analogues by PAMPA method
Absorption-Excipient-pH Classification Gradient Maps: Sparingly-Soluble Drugs and the pH Partition Hypothesis
Membrane-water partitioning, membrane permeability, and baseline toxicity of the parasiticides ivermectin, albendazole, and morantel
Permeation of permanently charged molecules through artificial membranes - influence of physicochemical properties
PAMPA—critical factors for better predictions of absorption
PAMPA - a Drug Absorption in vitro Model. 13. Chemical Selectivity due to Membrane Hydrogen Bonding: in combo Comparisons of HDM-, DOPC-, and DS-PAMPA
HT solubility and permeability: MAD-PAMPA analysis. (in Pharmacokinetic Profiling in Drug Reasearch: Biological, Physicochemical, and Computational Strategies)
PAMPA-Excipient Classification Gradient Maps
Caco-2 Permeability of Weakly Basic Drugs Predicted with the Double-Sink PAMPA pKa flux Method
Advances in Screening for Membrane Permeability: High-Resolution PAMPA for Medicinal Chemists
The Rise of PAMPA
PAMPA - a drug absorption in vitro model. 7. Comparing rat in situ, Caco-2, and PAMPA permeability of fluoroquinolones
Absorption using the PAMPA Approach (in Optimization in Drug Discovery: In Vitro Methods)
PAMPA - a Drug Absorption in vitro Model. 8. Apparent Filter Porosity and the Unstirred Water Layer
PAMPA - a Drug Absorption in vitro Model. 11. Matching the in vivo Unstirred Water Layer Thickness by Individual-Well Stirring in Microtitre Plates
Acid-Base Cosolvent Method for Determining Aqueous Permeability of Amiodarone, Itraconazole, Tamoxifen, Terfenadine and Other Very Insoluble Molecules
In vitro permeability of poorly aqueous soluble compounds using different solubilizers in the PAMPA assay with liquid chromatography/mass spectrometry detection
PAMPA - a drug absorption in vitro model. 5. Unstirred water layer in iso-pH mapping assays and pKa flux - optimized design (pOD-PAMPA)
In vitro trans-monolayer permeability calculations: often forgotten assumption
High throughput physicochemical profiling for drug discovery
Permeability through DOPC/dodecane membranes: measurement and LFER modelling
A comparison of the in vitro permeation of niacinamide in mammalian skin and in the Parallel Artificial Membrane Permeation Assay (PAMPA) model
Studying transdermal patches using Skin PAMPA
Studying semi-solid formulations of diclofenac using Skin PAMPA
Application of Skin Pampa™ to Cosmetic Solvent Screening
Using Skin-PAMPA For Transdermal Patch Testing
Novel HT Method for Parallel Excipient/Vehicle Formulation Studies
Assessment of Transdermal Penetration Enhancement by Topical Pharmaceutical Excipients Using Skin PAMPA Method
Application of Skin PAMPA to Differentiate Between Topical Pharmaceutical Formulations of Ibuprofen
Skin-PAMPA: Fast Prediction of Skin Penetration
Skin-PAMPA: A New Method for Fast Prediction of Skin Penetration
Developing Skin PAMPA for Transdermal Patches
Evaluation of Optimized Caco-2 Permeability Measurements
Human Jejunal Permeability Predicted from Caco-2 Assay - A Biophysical Model Applied to Fluoroquinolone Antimicrobials
Very Thin PAMPA Membranes Indicate Higher Antipyrene Permeability but are Fragile and Contain Leaky Water Pores
Prediction of in situ Blood-Brain Barrier Permeability using BBB PAMPA Model
Drug Permeation in Skin PAMPA and Franz Cell Model
Penetration Enhancer Effect of Sucrose Esters
Novel in vitro PK (non-animal PK) Assay for Excipient/Vehicle Formulation Studies
Prediction of Caco-2 pH-Dependent Permeability based on High Quality in vitro Training Set
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