Isonicotinyl hydrazide (INH) was chosen as a model drug, and was covalently attached to glyceryl phosphatide as the hydrophobic moieties of the phospholipid derivative. Isonicotinyl hydrazide phospholipid derivative liposome was prepared by thin-film hydration and sonication method. Drug encapsulation efficiency and drug to lipid molar ratio of the liposome were increased from 2% to nearly 100% and from 0.1~0.3 to 2.0 respectively. Liposomes with different sizes were prepared by controlling concentration of the phospholipid derivative and sonication time. The liposomes showed remarkable controlled drug release property when compared with a free drug. This novel liposome provides a new way for encapsulating drugs more especially.

Key words: liposome, encapsulation efficiency, isoniazid, phospholipid derivative, controlled release