Capreomycin is used for the treatment of multidrug-resistant tuberculosis (MDR-TB), but it is limited therapeutically by its severe side effects. The objectives of the present studies were (i) to design low-density porous capreomycin sulfate particles for efficient pulmonary delivery to improve local and systemic drug bioavailability and capacity to reduce the bacillary load in the lungs in a manner similar to that achieved with intramuscular injections; (ii) to determine pharmacokinetic parameters after pulmonary administration of these capreomycin particles; and (iii) to evaluate the efficacy of these particles in treating animals in a small-aerosol-inoculum guinea pig model of TB. Capreomycin particles were manufactured by spray drying and characterized in terms of size and drug content. Pharmacokinetic parameters were determined by noncompartmental methods with healthy guinea pigs after administration of capreomycin particles by insufflation. The efficacy of the particles was evaluated by histopathological analysis and in terms of wet organ weight and bacterial burden in TB-infected animals. Lungs of animals receiving a 14.5-mg/kg dose of capreomycin particles showed significantly lower wet weights and smaller bacterial burdens than those of animals receiving any other treatment. These results were supported by histopathological analysis. The feasibility of inhaling capreomycin in a novel powder form, with the ultimate objective of the treatment of MDR-TB, is demonstrated by pharmacokinetic and pharmacodynamic studies with guinea pigs. If applied to humans with MDR-TB, such a therapeutic approach might simplify drug delivery by eliminating injections and might reduce adverse effects through lowering the dose.Worldwide, there is an increase in multiple drug-resistant tuberculosis (MDR-TB), including reports of outbreaks of extensive MDR-TB in several countries (4, 36). Patients suffering from MDR-TB have infections which are resistant to at least two key drugs in the first-line regimen, namely, rifampin and isoniazid, in part as a consequence of poor compliance to the current first-line regimen (approximately 23% of active TB patients presently complete first-line treatment) (5). To treat MDR-TB, other, second-line antibiotics are needed and therapy lasts up to 2 years, typically requiring parenteral injection (2).Among the drugs injected is the polypeptide antibiotic capreomycin, the only second-line drug specifically indicated for MDR-TB. Capreomycin is a complex of four microbiologically active components that has been shown to be effective in combination with other appropriate anti-TB drugs in the treatment of pulmonary Mycobacterium tuberculosis infections when the primary agents (in particular isoniazid and rifampin) have become ineffective as a result of bacterial resistance or toxicity. The drug is painful to receive by injection and is associated with serious side effects, such as anorexia, thirst, anemia, and notably, nephrotoxicity and damage to the auditory and vestibular divisions of cranial nerv...

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Our results indicate that rifampicin can be formulated into an aggregated nanoparticle form that, once delivered to animals, achieves systemic exposure and extends levels of drug in the lungs.

By manufacturing a single-particle system in two particulate forms (i.e., micrometer size and nanometer size), we have designed a bacterial vaccine form that exhibits improved efficacy of immunization. Microstructural properties are adapted to alter dispersive and aerosol properties independently. Dried ''nanomicroparticle'' vaccines possess two axes of nanoscale dimensions and a third axis of micrometer dimension; the last one permits effective micrometer-like physical dispersion, and the former provides alignment of the principal nanodimension particle axes with the direction of airflow. Particles formed with this combination of nano-and micrometer-scale dimensions possess a greater ability to aerosolize than particles of standard spherical isotropic shape and of similar geometric diameter. Here, we demonstrate effective application of this biomaterial by using the live attenuated tuberculosis vaccine bacille Calmette-Gué rin (BCG). Prepared as a spray-dried nanomicroparticle aerosol, BCG vaccine exhibited high-efficiency delivery and peripheral lung targeting capacity from a low-cost and technically simple delivery system. Aerosol delivery of the BCG nanomicroparticle to normal guinea pigs subsequently challenged with virulent Mycobacterium tuberculosis significantly reduced bacterial burden and lung pathology both relative to untreated animals and to control animals immunized with the standard parenteral BCG.bacillus Calmette-Gué rin ͉ inhaled particles ͉ live-attenuated vaccines ͉ spray drying ͉ tuberculosis A erosol vaccination via the lungs targets an epithelium critical to host defense against inhaled pathogens (1), potentially avoids needle injection, and provides an exciting opportunity in the development of a newer and more effective tuberculosis (TB) vaccine. Published studies of inhaled vaccines for measles, influenza, and TB (2) have mostly involved nebulized solutions, a process that necessitates large volumes of water with long administration times; dried forms of vaccines, as formed traditionally by freeze drying and recently by spray drying (15), present an alternative to nebulization but pose risks to the integrity of dried bacteria and produce powders with suboptimal dispersive characteristics. Here, we show that by designing bacterial vaccines via rapid drying we can exploit the natural tendency of dried bacteria to assume elongated shapes and achieve remarkably effective airborne properties that combine the positive attributes of their submicrometer radial axes and micrometer-scale longitudinal axes. We demonstrate vaccine delivery from an inhaler designed for delivery to newborns. Furthermore, we report better TB protection with an aerosol form of bacillus Calmette-Guérin (BCG) than is achievable by standard s.c. and intradermal injection using a low-inoculum, aerosol infection and challenge in the sensitive guinea pig model. ResultsIn initial experiments, powders of dry bacteria were prepared by spray drying with a model nonpathogenic Mycobacterium, Mycobacterium smegmatis. We added a sec...

The pulmonary route of administration has proven to be effective in local and systemic delivery of miscellaneous drugs and biopharmaceuticals to treat pulmonary and non-pulmonary diseases. A successful pulmonary administration requires a harmonic interaction between the drug formulation, the inhaler device, and the patient. However, the biggest single problem that accounts for the lack of desired effect or adverse outcomes is the incorrect use of the device due to lack of training in how to use the device or how to coordinate actuation and aerosol inhalation. This review summarizes the structural and mechanical features of aerosol delivery devices with respect to mechanisms of aerosol generation, their use with different formulations, and their advantages and limitations. A technological update of the current state-of-the-art designs proposed to overcome current challenges of existing devices is also provided.