Improved Drug Delivery: Spray Freeze Dried Nano-Liposomal Inhaled Aerosols - Spray Freeze-Drying

Improved Drug Delivery: Spray Freeze Dried Nano-Liposomal Inhaled Aerosols
Wang, Zhaolin, L?ebenberg, Raimar, Sweeney, Lyle, Wong, Jonathan P., Finlay, Warren H.
2004
IEEE
Abstract
A novel powder formulation for inhaled aerosol drug delivery of nano-liposomes has been prepared using spray-freeze drying. After saline reconstitution 91% of the liposome particles (mean volume size) were found to be smaller than 600 nm. Upon aerosol dispersion, a fine particle fraction (FPF) of more than 80% was achieved for this formulation with a model drug (ciprofloxacin) using a new passive inhaler (patent pending) at an inhalation flow rate of 60 l/min.
Drug encapsulation efficiencies in various aqueous media were also measured. Encapsulation was 50% in water, 93.5% in isotonic saline, 80% in bovine mucin, 75% in porcine mucus and 73% in fivefold diluted ex vivo human cystic fibrosis patient sputum. In vivo experiments were also performed, in which formulations with fluorescence were delivered into the lungs of living mice for visualization of biodistribution and particle characteristics. Images from mouse lung tissue sections demonstrated successful delivery of the formulation into mice airspaces and spontaneous formation of liposomes in the mice lungs.