Single step bottom-up process to generate solid phospholipid nano-particles

Abstract

Context: The particularity of the Nano Spray Dryer B-90 is the nozzle containing a mesh vibrating at ultrasonic frequency.

Objective: To study process parameters and processability of crude phospholipid dispersions, in particular the effect of concentration and mesh aperture on both particle size of the dry solid phospholipid nano-particles and on the re-dispersed powder.

Materials and methods: Phospholipid dispersions containing trehalose as a stabilizer were spray dried. Particle size distributions of dry powders were evaluated by SEM micrographs and by PCS and cryo-TEM for the re-dispersed particles.

Results: Spray drying of crude liposome dispersions revealed solid phospholipid nano-particles. Aperture of nozzle mesh and concentration of the dispersions, respectively, both increased the size of solid phospholipid nano-particles. For crude dispersions, an upper limit with respect to processability was found close to below 10% (m/m) even if the crude dispersion was passed along the mesh several times; however, more effective dispersing methods such as pre-sonication can push the limit of processability to higher values.

Discussion and conclusion: The nano spray dryer is capable of spray drying crude dispersions of phospholipids in concentrations below 10% (m/m) generating solid phospholipid nano-particles relevant for pulmonary delivery. Re-dispersion of spray dried powder reveals liposomes.

• Drug delivery
• nano spray dryer B-90
• particle engineering
• particle size
• spray dry

Acknowledgements

The authors greatly acknowledge Prof. Per Morgen, Rajnish Dhiman and Danny Kyrping for training on the SEM, and Prof. Andrew Bond and Dr Artem O. Surov for training and use of the PXRD.