chemical properties - preformulation (click here)
BCS classification of drugs & its significant
- The BCS is a scientific framework for classifying drug substances based on their Aqueous Solubility and Intestinal Permeability.
- When combined with the dissolution of the drug product, the BCS take into account three major factors that govern the rate and extent of drug adsorption from IR solid oral dosage forms. These factors are Dissolution, Solubility and Intestinal Permeability.
- The aim of the BCS is to provide a regulatory tool for the replacement of certain BE studies by conducting accurate in-vitro dissolution tests.
According to the BCS, Drug substances are classified as follows:
- Class I - High Permeability, High Solubility
- Class II - High Permeability, Low Solubility
- Class III - Low Permeability, High Solubility
- Class IV - Low Permeability, Low Solubility
Class I - High Permeability, High Solubility
- Drugs dissolved rapidly.
- Drugs absorbed rapidly.
- Rapid therapeutic action.
- Excellent property.
- Ideal for oral route.
- e.g. Metoprolol, Diltiazem, Verapamil, Propranolol.
Class II - High Permeability, Low Solubility
- Drugs dissolved slowly.
- Drugs absorbed rapidly.
- Controlled released drugs.
- Oral / IV route for administration.
- e.g. Glibenclamide, Ezetimibe, Phenytoin, Nifedipine.
Class III - Low Permeability, High Solubility
• Dissolved rapidly
• Absorbance is limited
• Incomplete bioavailability
• Oral / IV route for administration
• e.g. Cimetidine, Acyclovir, Captopril
Class IV - Low Permeability, Low Solubility
• Low dissolution rate
• Low permeability property
• Slow or low therapeutic action
• IV or other routes are required
• e.g. Hydrochlorothiazide
Significance of BCS
- Regulatory toll for replacement of certain BE studies.
- It can save both time and money - if the immediate - release, orally administered drug meets specific criteria, and the FDA will grant a waiver for expensive and time consuming bio-equivalence studies.
- Valuable tool for formulation scientist for selection of design of formulated drug substance.
- When integrated with other information provides a tremendous tool for efficient drug development.
- Reduces cost and time of approving scale-up and post approval challenges.
- Applicable in both pre-clinical and clinical drug development process.
- Works as a guiding tool in development of various oral drug delivery systems.