Liposomes composed of partially hydrogenated egg phosphatidylcholines: fatty acid composition, thermal phase behavior and oxidative stability.
Partially hydrogenated egg phosphatidylcholines (PHEPC) represent a new class of raw materials for liposome-based drug products. PHEPC were manufactured from native egg phosphatidylcholine (EPC) to iodine values (IV) 40, 30, 20, 10, and 1. Hydrogenation resulted in a complete loss of arachidonic acid (20:4) and docosahexaenoic acid (22:6) in IV 40 EPC and a progressive conversion of linoleic (18:2) and oleic acid (18:1) to stearic acid (18:0) at higher degrees of hydrogenation (IV 30, 20, 10, 1). Hydrogenation lead to formation of trans-fatty acid isomers maximally 18.5 mol% in IV 20 EPC. Liposomes made from IV 20, IV 10 and IV 1 EPC had marked phase transitions between 20 and 60 degrees C. PHEPC showed increased resistance to oxidation as measured by oxygen uptake during 2,2'-azobis-(2-amidinopropane) hydrochloride (AAPH) initiated accelerated oxidation. Various applications of these new materials in the manufacture of liposomes and liposome based drug products are discussed.
Lang
J
J
Liposome Technology, Inc., Menlo Park, CA 94025.
Vigo-Pelfrey
C
C
Martin
F
F
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002849:Chromatography, Gas; D004355:Drug Stability; D004531:Eggs; D005227:Fatty Acids / Q000032:analysis; D006358:Hot Temperature; D008081:Liposomes; D010084:Oxidation-Reduction; D010713:Phosphatidylcholines; D013237:Stereoisomerism
D005227:Fatty Acids; D008081:Liposomes; D010713:Phosphatidylcholines