Spray freeze-drying for inhalation application: process and formulation variables

Abstract

High porous particles with specific aerodynamic properties were processed by the spray freeze-drying (SFD) method. Comprehensive knowledge about all aspects of the SFD method is required for particle engineering of various pharmaceutical products with good flow properties. In this review, different types of the SFD method, the most frequently employed excipients, properties of particles prepared by this method, and most recent approaches concerning SFD are summarized. Generally, this technique can prepare spherical-shaped particles with a highly porous interior structure, responsible for the very low density of powders. Increasing the solubility of spray freeze-dried formulations achieves the desired efficacy. Also, due to the high efficiency of SFD, by determining the different features of this method and optimizing the process by model-based studies, desirable results for various inhaled products can be achieved and significant progress can be made in the field of pulmonary drug delivery.

Graphical Abstract

Keywords:

• Spray freeze-drying
• aerodynamic properties
• particle engineering
• pulmonary drug delivery
• inhaled products

Disclosure statement

The author(s) expressed no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Additional information

Funding

This study was supported by the Tehran University of Medical Sciences, Tehran, Iran.