Cryoprotective effects of cycloinulohexaose on freezing and freeze-drying of liposomes.
Cycloinulohexaose (CF-6) maintained the membrane structure of the liposomes during freeze-thawing, and thus CF-6 was very effective in inhibiting both drug leakage from liposomes and the size change of liposomes during freezing and freeze-drying. As the ratio of CF-6 to lipid increased from 1 to 5, calcein retention in the liposomes increased from 70% up to 85% and a maximum retention was obtained at a ratio of more than 2. The addition of glycerol enhanced the above cryoprotective effect of CF-6 and improved calcein retention up to 90%. Neither detectable leakage of calcein nor particle size change was observed after the storage of liposomes freeze-dried with CF-6 for 6 months at 4 and 25 degrees C.
Ozaki
K
K
Pharmaceuticals Development Laboratory, Mitsubishi Chemical Corporation, Ibaraki, Japan.
Hayashi
M
M
D002152:Calorimetry, Differential Scanning; D002240:Carbohydrate Sequence; D003451:Cryoprotective Agents / Q000737:chemistry*; D005452:Fluoresceins / Q000737:chemistry; D005612:Freeze Drying; D007202:Indicators and Reagents; D008081:Liposomes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry*; D010316:Particle Size
D003451:Cryoprotective Agents; D005452:Fluoresceins; D007202:Indicators and Reagents; D008081:Liposomes; D009844:Oligosaccharides; C102956:cycloinulohexaose CF6; C007740:fluorexon