RESUMO
PURPOSE: An inhalable dry powder formulation of tranexamic acid (TA) was developed and tested in a novel high-dose Orbital® multi-breath inhaler. The formulation was specifically intended for the treatment of pulmonary haemorrhage and wound healing associated with haemoptysis. METHODS: Inhalable TA particles were prepared by spray drying and the powder characterised using laser diffraction, electron microscopy, thermal analysis, moisture sorption and X-ray powder diffraction. The aerosol performance was evaluated using cascade impaction and inline laser diffraction and interaction with epithelia cells and wound healing capacity investigated using Calu-3 air interface model. RESULTS: The spray dried TA particles were crystalline and spherical with a D0.5 of 3.35 µm. The powders were stable and had limited moisture sorption (0.307%w/w at 90%RH). The Orbital device delivered ca. 38 mg powder per 'inhalation' at 60 l · min(-1) across four sequential shots with an overall fine particle fraction (⩽ 6.4 µm) of 59.3 ± 3.5% based on the emitted mass of ca. 150 mg. The TA particles were well tolerated by Calu-3 bronchial epithelia cells across a wide range of doses (from 1 nM to 10nM) and no increase in inflammatory mediators was observed after deposition of the particles (a decrease in IL-1ß, IL-8 and INFγ was observed). Time lapse microscopy of a damaged confluent epithelia indicated that wound closure was significantly greater in TA treated cells compared to control. CONCLUSION: A stable, high performance aerosol of TA has been developed in a multi-breath DPI device that can be used for the treatment of pulmonary lesions and haemoptysis.
