For a strategy based on inhalation therapy for tuberculosis by a Dry Powder Inhaler (DPI) device, powder physical properties play a crucial role on powder deposition onto alveolar epithelium and macrophage phagocytosis. The study aimed to assess the role of parameters involved in freeze-drying process of Solid Lipid Microparticles (SLM) loaded with rifampicin, a first-line anti-TB drug. Excellent breathability in terms of both emitted dose (∼95%) and breathable fraction (∼90%), better than that obtained by cryoprotectants, was achieved by sample water dilution and freezing at a very low temperature before freeze-drying. These results indicate the relevant role of the ice crystal structure on SLM aggregation for a superior DPI performance.