Effects of lyophilization on liposome stability determined

Effects of lyophilization on liposome stability determined
2005 MAY 6 - (NewsRx.com) -- The effects of lyophilization on the stability of drug-loaded liposomes have been determined.
In a recent study from Macedonia, "[m]ultilamellar liposomes containing 5-fluorouracil (5-FU) were prepared by modified lipid film hydration method and were lyophilized with or without saccharose as cryoprotectant."
"The effect of lyophilization on the stability of liposomes was evaluated by comparing the vesicle size, encapsulation efficiency and the drug release rate before and after lyophilization/rehydration," explained M. Glavas-Dodov and coauthors at Sv. Kiril and Metodij University.
"The process of lyophilization, without cryoprotectant, resulted in particle size increase and significant content leakage," test results revealed. With "the addition of saccharose, the lipid bilayers become more stable and less permeable to the encapsulated drug; saccharose imparted 5-FU retention of about 80% after lyophilization/rehydration."
"Freeze-drying did not affect the particle size of liposomes containing saccharose as cryoprotectant," according to the report. "The drug release profiles of rehydrated liposomes followed Higuchi's square root model."
"Also, the obtained release profiles were all biphasic: a rapid initial drug release phase (burst release of the portion of the drug that leaked out of liposomes during the lyophilization) was followed by a slower, approximately constant drug release phase (zero-order kinetics)," the researchers noted in conclusion.
Glavas-Dodov and colleagues published the results of their study in the International Journal of Pharmaceutics (The effects of lyophilization on the stability of liposomes containing 5-FU. Int J Pharm, 2005;291(1-2 Sp. Is):79-86).
For additional information, contact M. Glavasdodov, Sv. Kiril and Metodij University, Faculty of Pharmacy, Department of Pharmaceutical Technology, Vodnjanska 17, Skopje, Macedonia.
The publisher of the International Journal of Pharmaceutics can be contacted at: Elsevier Science BV, PO Box 211, 1000 AE Amsterdam, the Netherlands.
Keywords: Skopje, Macedonia, Liposomal Drug Encapsulation, Biotechnology, Drug Delivery, Medical Devices and Pharmaceutical & Drug Development.