Microparticulate drug delivery systems have been studied by the researchers for several years for various applications including targeted drug delivery, reduced drug toxicity and enhanced bioavailability of drug molecules. These microparticles can range from 1-200 μm for most of these applications. These micron sized drug delivery systems can be prepared using different techniques, such as, spray drying, emulsion method, jet milling, adsorption and solvent evaporation, fluidization/ solvent precipitation, phase separation and interfacial polymerization methods. Literature validates that various polymers have been used to prepare microparticles using these techniques, ranging from natural polymers (albumin, gelatin, chitosan, starch, amylodextrins, cellulose derivatives etc.) to synthetic polymers (poly glycolic acid- PLGA, poly vinyl alcohol-PVA etc.) based on the study requirements.
Several research studies have reported the use of microparticles to enhance oral bioavailability of drug molecules. Zhang et al. described the use of carboxylated mesoporous carbon microparticles (cMCMs) to increase the oral bioavailability of carvedilol, a poorly water soluble beta-blocker. Here, the cMCMs were prepared by adsorption and solvent evaporation technique. These rod-like particles were 1-2 μm long and 0.5 μm in diameter. The study concluded that the use of the cMCMs can enhance the bioavailability of carvedilol by 179.3% compared to the commercial product.