FDA has issued the guidance, Dissolution Testing and Specification Criteria for Immediate-Release Solid Oral Dosage Forms Containing Biopharmaceutics Classification System Class 1 and 3 Drugs (August 2015). This will supersede the guidance issued in August 1997 for BCS Class 1 and 3 drug substances in immediate-release drug products that meet the criteria of the guideline. For Class 2 and 4 drug substances, continue to refer to the 1997 guidance document. Class 2 is Low solubility-High Permeability Drugs, while Class 4 is Low solubility-Low Permeability Drugs. The guideline applies to solid oral dosage forms and not chewable or orally disintegrating tablets.
Download the guidance here.