Suggestions for PAMPA

The following recommendations are a good starting point for a gastrointestinal, noncell-based artificial membrane permeability assay [70]  

Alternatively, a well-validated poorly permeable compound is included in the analyte solutions as an internal standard. A compound such as theophylline has an effective permeability of 0.12 x 10 scm/s (exact value will depend on assay conditions). If the compound were seen to be permeating significantly faster than this effective permeability, it could be concluded that the membrane had been compromised. This approach would mean that a detection method based on separation, such as HPLC, would be needed. Upon the inclusion of a second internal standard, which was known to be highly soluble, such as verapamil, effective permeability 16 x lCTscm/s would enable monitoring of the incubation time to ensure that equilibrium had not been reached for highly permeable compounds. 

A third method of checking the membrane integrity is to monitor the appearance of DMSO in the receiver wells due to damaged membranes by analyzing down to 200 nm. This could be automated, would not result in the need for separation of the analyte before detection, and would not reduce throughput. 

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