chitosan and plga microspheres as drug delivery ... - UniCA Eprints

3. Aim of the WorkDuring the last three decades, therapeutic systems based on polymers, both natural andsynthetic, have shown to be effective in controlling rate or time of drug release, in enhancingdrug targeting specificity while lowering systemic drug toxicity, and providing protection forpharmaceuticals against degradation.An important consideration in the treatment of pulmonary infections is the fact that the MTBand MAC have the capability of surviving intra-cellulary in the host macrophages for longperiods of time (246). Therefore, the ability of the antibacterial agent to eradicate themicrorganisms within the macrophage is of key importance.However, most of the anti-mycobacteria drugs presently in use fail to penetrate macrophages.For this reason, many researchers are considering the use of appropriately engineered deliverysystems for these drugs, in order to make them therapeutically effective. It is well known thatmicro-encapsulation technology can be used to accomplish sustained release of antibiotics,when they are formulated in larger sizes than 50 µm, or to target drug delivery systems tospecific cells (i.e., macrophages), when antibiotics are formulated in smaller sizes