Study on in vitro stability of polymerized liposomes.

We studied the stability of liposomes composed of polymerized phospholipid, 1,2-bis-(octadeca-2,4-dienoyl)-sn-glycero-3-phosphocholine (DENPC), to pH changes and the presence of bile salts, monitoring the leakage of 3H-sucrose entrapped in liposomes. The stability of polymerized DENPC-liposomes to acidic media (pH 3.3 and 2), and the presence of bile salts (20 mM), was much higher than that of nonpolymerized DENPC-liposomes and liposomes composed of conventional phospholipids. The stability of polymerized DENPC-liposomes was increased in the presence of carboxymethyl chitin (CM-chitin).