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DRYING TECHNIQUE IMPACT ON LIPOSOMAL MICROPARTICLES: A COMPARATIVE STUDY OF FREEZE-DRIED AND SPRAY DRIED FORMULATION FOR LUNG DELIVERY

HUNER KAMAL OMER

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The drying process plays a critical role in determining the physicochemical and aerosolization properties of pulmonary drug delivery systems. This study compares freeze-drying (FD) and spray-drying (SD) for the preparation of liposomal microparticles intended for inhalation. Beclomethasone dipropionate-loaded liposomes were prepared by dissolving the lipophilic components (soy phosphatidylcholine, SPC, and Cholesterol, CH; total 100 mg) in absolute ethanol (120 mg) at 70°C. The aqueous trehalose solution was then added, resulting in phospholipid:carrier mass ratios of 1:5 and 1:10 (w/w). FD produced a greater yield compared to SD, but vesicle size was reduced in SD. Zeta potential values were similar across all formulations, while FD vesicles retained higher entrapment efficiency. X-ray diffraction confirmed that both methods yielded less crystalline particles. SEM images revealed that FD particles were irregular, whereas SD particles were spherical. Aerosolization studies demonstrated superior performance of SD formulations, with higher emitted dose, improved Carr’s index, and lower MMAD. Under the studied conditions, SD formulations showed superior in vitro aerosolization performance, whereas FD achieved higher production yield and entrapment efficiency.