[New tendencies in controlled drug release--liposomes entrapped in polymer matrices].

Liposomes entrapment in different forms of polymers represents in the last few years a method to modify the drug release kinetics in order to attend the specificity of this phenomenon. This will result generally in complex systems in which liposomes are dispersed in polymer matrices like gels, hydrogels and microparticles. As a consequence the drug release will be influenced by both polymer matrix and small carrier entrapped in. The researchers are trying to control the release of drug from such solid complex system by modulating not only the vesicle properties but also those of polymer support. This kind of system is necessary also for the cases when time stable liposomes are desired, being already well known that the major drawback of this type of carrier is the stability in time and in different physiologic conditions.