[Preparation and structural determination of lyotropic lamellar liquid crystalline systems of pharmaceutical importance]].

Lamellar lyotropic liquid crystalline systems are thermodynamically stable, optically isotropic continuous compositions composed of particles of a few nanometeres in diameter which are formed spontaneously or with a low energy input in the definite proportions of the given components [8, 27]. New possibilities for the development of controlled drug delivery systems are inherent in these systems in consequence of their stability and special, skin friendly structure [3]. The present aim was to formulate and study two- or multicomponent compositions with a relatively low surfactant content, composed of materials official in the pharmacopoeia and suitable for therapeutic purposes. Macroscopic examination of the samples was carried out, together with polarizing light microscopy [5, 28] and transmission electron microscopic observation of replicas produced by the freeze-fractured technique [29-31] for the purpose of demonstrating the presence of lamellar liquid crystalline domains. The interlamellar repeated distance confirming the existence of a regular structure was determined by means of X-ray diffraction [26, 32].