ENTRAPMENT OF NEW BETA-BLOQUANTS IN EGG L ECITHIN LIPOSOMES - RELATIONS BETWEEN CHEMICAL-STRUCTURE AND RELEASE KINETICS OF THE DRUGS

Phospholipid liposomes were prepared from egg phosphatidylcholine acco rding to the injection method. Turbidity measurements and dynamic ligh t scattering were used to characterize the liposomes and to study thei r stability during storage. The injection method gives reproductible a nd stable liposome suspensions. The liposomes were small unilamellar v esicles (SUV) with a mean diameter of about 100 nm. New beta-bloquants and sodium salicylate have been entrapped in liposomes and release ki netics has been studied. The entrapment efficiency was correlated to t he octanol/water partition coefficients of the drugs. The relation bet ween drug lipophilicity and release kinetics have been discussed using two different kinetic models.