RT Journal Article SR Electronic T1 Protection of a Model Protein, Lactate Dehydrogenase, by Encapsulation in Liposome JF PDA Journal of Pharmaceutical Science and Technology JO PDA J Pharm Sci Technol FD Parenteral Drug Association (PDA) SP 213 OP 218 VO 50 IS 4 A1 Sandeep Nema A1 Kenneth E. Avis YR 1996 UL http://journal.pda.org/content/50/4/213.abstract AB The objective of this study was to determine if encapsulating a model protein, lactate dehydrogenase (LDH), inside liposomes can protect it during storage, upon freeze-thaw cycles and during freeze-drying. LDH, which undergoes cold denaturation, was entrapped insides liposomes prepared using modification of Bangham's method. It was found that when LDH was entrapped in liposomes and subjected to a single freeze-thaw treatment, there was about 7 times more recovery of activity than when LDH was free in solution. Similarly, LDH encapsulated in liposomes showed 60% recovery after freeze-drying compared to 1–2% recovery for the unentrapped LDH. The role of phospholipid content, residual moisture content and protein content were evaluated. Possible mechanism(s) of cold temperature inactivation of proteins and role of liposomes in preventing such cryodenaturation will be discussed in light of these results.