Abstract:

Self-assembled lyotropic liquid crystals (LLCs) of lipids and water are interesting mesophases that can be considered among other applications as delivery vehicles due to their remarkable structural complexity. The phase behavior of mixtures of glycerol monooleate (monoolein, GMO) and phytantriol were particularly well studied in drug delivery systems, food products, and encapsulation and crystallization of proteins. We are summarizing in this chapter our contribution to modified LLCs and their structural features and recent systematic efforts to utilize them for solubilization, and potential release of drugs and biomacromolecules. Some of the most interesting applications are the implementation of peptides and proteins in the reversed cubic and hexagonal mesophases, to enhance penetrating pattern of a model drugs. LLC vehicles were shown to allow ``on demand'' targeted release, based on controlling the polymorphism of lyotropic liquid crystalline mesophases. A new pathway to responsive LLCs, enabling the controlled release of hydrophilic drugs diffusing through the water channels of the mesophases was also investigated. The system is capable of self-assembling into a reverse bicontinuous cubic phase of Im3m symmetry and transform into a reverse columnar hexagonal as a function of pH, pressure or enzymes. LLCs were shown to entrap several peptides enzymes, proteins and nucleotides into cubic and lamellar monoolein-based mesophases in order to protect them and enable their release. The main outcomes of the described research demonstrated that control of the physical properties of hexagonal LLC on different length scales is key for rational design of these systems as delivery vehicles for both low molecular weight therapeutics and biomacromolecules.