ABSTRACT
Disperse systems have been broadly classified as systems in which one substance, the dispersed phase, is distributed throughout another substance, the continuous phase or vehicle. They are important to pharmacy because of their widespread use. Pharmaceutical dosage forms that can be classified as disperse systems are suspensions, emulsions, creams, ointments, pastes, foams, suppositories, and aerosols. The initial dispersion of particles in a suspension requires wetting by the dispersion medium. If the material from which a suspension is prepared exhibits hydrophobic characteristics, it is difficult to remove air from the particle surface. Disperse dosage forms are usually administered parenterally, orally, and topically. The absorption barrier for each route of administration is the layer that is most resistant to drug penetration. Bioavailability can be simply defined as the measurement of the rate and extent of drug absorption.
