Chinna Reddy Palem

Dry powder inhalers (DPIs) represent a pivotal technology in pulmonary drug delivery, offering advantages such as improved stability, breath-actuated dosing, and enhanced patient convenience. This review presents an in-depth exploration of DPIs, from foundational principles to emerging innovations. Beginning with the historical development and physiological basis for pulmonary delivery, the review delves into the mechanisms of DPI function, highlighting the importance of aerodynamic particle behavior and key physicochemical properties. Critical formulation components such as active pharmaceutical ingredients, carrier particles, and excipients are examined alongside particle engineering and manufacturing technologies essential for scalable, high-quality production. Device design and aerosolization mechanisms are discussed in the context of usability, patient handling, and dose consistency. In vitro and in vivo performance evaluation techniques, including aerosol characterization, deposition studies, and pharmacokinetics, are reviewed. This review also captures recent advances in nanotechnology, biologics delivery, smart inhalers, and vaccine formulations. Regulatory frameworks, market dynamics, and current commercial DPI products are assessed to provide a comprehensive view of the global landscape. Finally, future directions are outlined, including personalized medicine approaches, sustainable inhaler technologies, and opportunities for innovation in systemic and respiratory therapies.

  Promethazine Hydrochloride (PMZ), a low bioavailabe drug, used for the management of emesis. The purpose of the present investigation was to develop buccoadhesive tablets for PMZ and to evaluate for their physicochemical, in vitro, ex vivo and in vivo parameters. Ex vivo drug permeation through porcine buccal membrane from the drug solution was conducted to know the permeation characteristics of the PMZ. The controlled-release PMZ tablets were produced by direct compression method using Sodium CMC and Carbopol 934P as mucoadhesive polymers and evaluated for in vitro drug release, in vitro bioadhesion, in vivo residence time, swelling and erosion studies, surface pH, ex vivo drug permeation through porcine buccal membrane from the optimized buccal tablet (F10) and stability studies. Formulation F10 showed maximum drug release (96.3 %) in 6 h, with the Higuchi model release profile and permeated 49.8 % of the drug with flux 1.45 mg h–1cm–2 through porcine buccal membrane. The optimized formulation showed peak detachment force (1.64 N), work of adhesion (0.36 mJ), in vivo residence time (287 min), swelling index (204%), erosion (53.1%) and surface pH (6.92). In vivo mucoadhesive behaviour of the optimized formulations was studied in healthy human volunteers and subjective parameters were evaluated. The stability of the optimized formulation was studied and no significant changes were detected in drug content and in vitro release after 6 months. PMZ mucoadhesive tablets for buccal delivery could be prepared with required permeation, bioadhesive and in vivo residence properties.