Positively charged rifampicin-loaded microspheres for lung delivery

Several advantages have been proposed for administering antitubercular drugs in particulate carriers including a reduction in the dose and frequency of administration, increasing patient compliance as well as targeting the drug to macrophages that harbour Mycobacterium tuberculosis. An important characteristic responsible for mucosal adsorption and translocation of particles through the mucosa is surface charge. In these investigations chitosan was used as an emulsion stabiliser in the preparation of rifampicin loaded PLGA, PCL and combined PLGA + PCL microspheres. Chitosan not only imparted a positive charge to the surface of the microspheres but was also able to increase their loading efficiency. Combined PLGA + PCL microspheres display substantially altered release kinetics which may be useful in the delivery of rifampicin and other agents that may benefit from sustained and controlled delivery profiles.