VARIOUS APPROACHES FOR PARTICLE SIZE REDUCTION FOR IMPROVEMENT OF ORAL BIOAVAILABILITY OF HYDROPHOBIC DRUGS

Noopur K. Gandhi*

ABSTRACT

Pharmaceutical particle technology is employed to improve poor aqueous solubility of drug compounds that limits in vivo bioavailability owing to their low dissolution rate in the gastrointestinal fluids following oral administration. The particle technology involves several approaches from the conventional size reduction processes to the newer. The conventional methods of size reduction involve mechanical micronization techniques that are simple and convenient methods to reduce the drug particle size and increase the surface area and thus enhance the solubility and dissolution of poorly soluble drugs. The conventional particle technologies are limited for some drugs due to their low efficiency hence novel particle technologies used to overcome the limitations of the conventional methods. Novel particle technologies modify the solubility properties of the drugs and produce solid, powdered form of the drugs that are readily soluble in water and can be easily formulated into various dosage forms. There are various techniques for improvement of oral bioavailability of hydrophobic drugs: 1) particle size reduction 2) mechanical micronization by jet milling, ball milling, and high pressure homogenization 3) engineered particle size control by cryogenic spray process, crystal engineering 4) some newer techniques are solid self emulsifying drug delivery system, complexation with cyclodextrin, polymeric micelles, freeze dried liposomes, solid liquid nanoparticles. Solid- SEDDS (S-SEDDS).

Keywords: Particle technology, Drug solubility, poorly water soluble drug, Solubility enhancement, Dissolution.