Liposomes have been utilized as a drug delivery system to increase the bioavailability of drugs and to control the rate of drug release at the target site of action. However, the occurrence of self-aggregation, coalescence, flocculation and the precipitation of aqueous liposomes during formulation or storage can cause degradation of the vesicle structure, leading to the decomposition of liposomes. To increase the stability of liposomes, post-processing techniques have been applied as an additional process to liposomes after formulation to remove water and generate dry liposome particles with a higher stability and greater accessibility for drug administration in comparison with aqueous liposomes. This review covers the effect of these techniques including freeze drying, spray drying and spray freeze drying on the stability, physicochemical properties and drug encapsulation efficiency of dry liposomes. The parameters affecting the properties of liposomes during the drying process are also highlighted in this review. In addition, the impact of using a protective agent to overcome such limitations of each process is thoroughly discussed through various studies.
Bibliographical noteFunding Information:
This research was supported by a grant from the Institute of Biomedical Science and Food Safety, the School of Life Sciences and Biotechnology for BK21PLUS, Korea University, Korea. This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2021R1A2C1012170).
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
- Freeze drying
- Liposome stability
- Post-processing techniques
- Spray drying
- Spray freeze drying
ASJC Scopus subject areas
- Pharmaceutical Science