Rheological Study of a Liposomal Hydrogel Based On Carbopol

The objective of this work was to investigate flow rheological properties of topical hydrophilic gels, containing liposomes loading dill volatile oil. It is well known that rheological properties of pharmaceutical systems for topical use influence the release rate of the contained active substances. Because of this, it is important to establish whether and to what extent the presence of liposomes or volatile oil determines changes of these characteristics. Liposomes composed of phosphatidylcholine and cholesterol and incorporating Anethi aetheroleum were prepared by thin film hydration method and dispersed into two types of hydrogels (0.5%, respectively 1% carbopol). The rheological measurements were performed at two different temperatures (23°C - storage temperature and 37°C - body temperature). The obtained data indicated for both the experimental hydrogels, at both temperatures, a thixotropic, non - Newtonian, pseudoplastic behavior. It was found that rheological parameters depend on the polymer concentration and on the nature of the incorporated form.