Class I drugs: high solubility

Class I Drugs (High Solubility and High Permeability)... 

Class I — Drug is highly soluble and highly permeable... 

BCS Class I High-solubility, high-permeability drugs. BCS Class I drugs are generally very well absorbed. An immediate release (IR) product of this class is... 

The drugs listed in the EML were classified according to the criteria explained above. Where no clear classification could be made, the worst case was assumed. For example if a substance is highly soluble, but absolute bioavailability data were not available, the test conditions for BCS Class III substances have been proposed. The same procedure was adopted for fixed combinations, for example amoxicillin and clavulanic acid, the testing procedure was always fixed according to the worst BCS classification, in this example clavulanic acid (BCS Class III/l), because amoxicillin is a BCS Class I drug. This combination would therefore be tested according to BCS Class III requirements. The results of the revised classification can be found in Tables 1-3. 

Class I Drugs with high solubility and high permeability (e.g. Metoprolol)... 

Class II drugs, i.e., low-solubility/high-permeability compounds, are expected to have a dissolution-limited absorption. Thus, for these types of drugs an IVIVC... 

Waiver of in vivo bioequivalence studies for major post approval manufacturing changes for the BCS Class I (Biopharmaceutics Classification System highly soluble, highly permeable and rapidly dissolving) solid oral products is NOT recommended for narrow therapeutic index drugs (17). 

Class I — High solubility-high permeability drugs ... 

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