Development and Evaluation of Dry Powder Inhalation System of Terbutaline Sulphate for Better Management of Asthma

Terbutaline sulphate (TBS), a bronchodilator (β2 agonist) has a short half-life, hence frequent administration (4-6 times a day) is necessary, resulting in patient compliance problems. Therefore long acting TBS inhalation formulations are desirable to improve patient compliance, reduce toxicity and hence achieve better management of asthma. Microparticulate dry powder inhalation delivery systems for sustained pulmonary drug delivery have been particularly attractive. In the present investigation, TBS loaded chitosan microspheres for pulmonary delivery were prepared by emulsification and ionotropic gelation method. The microspheres were characterized for drug content, particle size, densities, flow properties, moisture content and surface topography by SEM; in vitro drug release was evaluated in simulated lung fluid at 370 at pH 7.4. The respirable or fine particle fraction (FPF) was determined by using twin stage impinger (TSI). Further stability evaluation of TBS loaded DPI systems was carried out at 250/ 60% RH and at 400C/ 75% RH. Keywords: Turbutaline sulphate, microspheres, pulmonary delivery, Dry powder inhalation.