Evaluation of Nanocarrier-Based Dry Powder Formulations for Inhalation with Special Reference to Anti-Tuberculosis Drugs

Pulmonary tuberculosis (TB) is a leading cause of death worldwide and is caused by the pathogen Mycobacterium tuberculosis (MTb). As treatment for TB, dry powders for inhalation (DPIs) are considered stable compared with nebulizers and metered dose inhalers and are suitable for high-dose formulations. Although extensive research has been done over the last two to three decades on nanocarrier-based DPIs for targeting MTb infection, none of the anti-TB DPI formulations have reached the market. Challenges in the proper assessment of nanocarrier-based DPIs due to the complexity of lungs is one of the reasons. In this review, the details of in vitro evaluation parameters of nanocarriers and nanocarrier-based DPIs along with their need and basic principles are discussed. Further, the thorough in vitro, ex vivo, and in vivo pharmacological evaluations, together with their procedures wherever required, are covered. The different evaluation parameters during process development, release specifications, and stability studies suggested by U.S. Food and Drug Administration Center for Drug Evaluation and Research to apply for new drug applications and abbreviated new drug applications of DPIs are also discussed. Lastly, the evaluation parameters for DPIs provided in European, United States, British, and Indian pharmacopeias are summarized.