Dry Powder Inhalations: A pharmaceutical approach to treat pulmonary tuberculosis

Pankaj Patel, Santosh Kumar Kushwaha, Meenakshi Gupta, Royal Patel, Aarti Tiwari

Tuberculosis is transmitted by inhaling droplets containing Mycobacterium tuberculosis from an infected individual and is currently treated by WHO recommended multiple drug chemotherapy, Directly Observed Treatment Strategy (DOTS). The pharmaceutical dosage forms used to deliver these drugs are mostly tablets containing high dose of antitubercular drugs and some second line injectable. The problems associated with the oral formulations arise mostly due to high drug doses resulting in severe adverse effects. The prolonged use of the DOTS therapy also results in bacillary resistance resulting in incomplete sterilization. The inhalational therapy is a means of not only overcoming these adverse effects by lowering the dose required to sterilize the bacterium but also provides targeted delivery of the therapeutics to the infected macrophages and the surrounding lung tissue. Among the inhalation therapy, dry powder inhalation has been not explored in the clinical setup yet, but there is enough preclinical proof-of-concept to demonstrate the efficacy of these formulations in reducing the pulmonary burden as well as prevention of the disease relapse. Herein, we discuss the rationale of using dry powder inhalations and the various pharmaceutical techniques to formulate the dry powder inhalations for deep lung delivery.