title: Freeze-drying of liposomes using tertiary butyl alcohol/water cosolvent systems.
abstract: The objective of this study was to obtain dehydrated liposomes using a novel procedure that involves freeze-drying (FD) of liposomes with TBA/water cosolvent systems. The effects of TBA on the integrity/stability of vesicles of HSPC (or SPC):Cholesterol (4:1) were investigated. TBA used as a cosolvent was detrimental to SPC liposomes, leading to increased particle size and leakage of trapped calcein. However, this was not the case for HSPC liposomes. The vesicle size and the retention of trapped calcein after lyophilization from cosolvents were similar to those after FD from water alone. Moreover, the addition of TBA can significantly enhance the sublimation of ice resulting in short FD cycles. The resulting lyophilized cake can form a loose powder upon agitation, which flowed well enough to be easily poured from the vial. Thus FD of HSPC liposomes using TBA/water cosolvent systems can provide sterile powder for specialized applications. In addition, in conjunction with a modified injection method, this FD technology might be used to produce dehydrated HSPC liposomes on a large scale.
authors.affiliation: School of Pharmacy, Hebei Medical University, No. 361, ZhongShan East Road, Shijiazhuang City, Hebei Province 050017, PR China. cjxlib@hotmail.com
authors.forename: JingXia
authors.initials: J
authors.lastname: Cui
authors.forename: ChunLei
authors.initials: C
authors.lastname: Li
authors.forename: YingJie
authors.initials: Y
authors.lastname: Deng
authors.forename: YongLi
authors.initials: Y
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D002152:Calorimetry, Differential Scanning; D002784:Cholesterol / Q000737:chemistry; D020285:Cryoelectron Microscopy; D005452:Fluoresceins / Q000737:chemistry; D005612:Freeze Drying; D008055:Lipids / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry*; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013395:Sucrose / Q000737:chemistry; D014867:Water / Q000737:chemistry*; D020002:tert-Butyl Alcohol / Q000737:chemistry*
chemical_list: D005452:Fluoresceins; D008055:Lipids; D008081:Liposomes; D010713:Phosphatidylcholines; D012997:Solvents; D014867:Water; D011092:Polyethylene Glycols; D013395:Sucrose; D002784:Cholesterol; D020002:tert-Butyl Alcohol; C007740:fluorexon