Development and Evaluation of a Polyherbal Dry Powder Inhaler for Pulmonary Delivery in Management of Tuberculosis

Abstract

Pulmonary tuberculosis remains a major global health challenge, and while conventional oral therapies are effective, they are often limited by systemic toxicity, extensive first-pass metabolism, and poor patient adherence. This study aimed to develop and evaluate a polyherbal dry powder inhaler (DPI) for localized pulmonary delivery using a simple carrier-based blending technique. Standardized extracts of Adhatoda vasica, Curcuma longa, Glycyrrhiza glabra, and Piper nigrum were combined in a fixed ratio and blended with lactose monohydrate to prepare three DPI formulations (F1–F3). Micromeritic evaluation revealed improved flowability and reduced particle size with increasing carrier concentration, with F3 demonstrating the most favorable characteristics. Aerodynamic analysis using the Next Generation Impactor showed that F3 achieved the highest emitted dose and fine particle fraction, along with an MMAD suitable for deep lung deposition. Drug content and uniformity assessments confirmed consistent distribution of phytoconstituents within the carrier matrix, while in vitro cytotoxicity studies on A549 cells indicated good biocompatibility. Stability testing under accelerated conditions demonstrated minimal changes in particle size, drug content, and aerosolization behavior over 90 days. Overall, formulation F3 emerged as the optimized DPI, offering a promising approach for delivering anti-inflammatory and immunomodulatory phytoactives directly to pulmonary tissues. The developed system may serve as a supportive or adjunctive therapy in the management of pulmonary tuberculosis, warranting further in vivo and clinical investigations.