Cubic liquid-crystalline particles as protein and insoluble drug delivery systems

Based on the scientific understanding of lipid particulate systems, many scientists have pursued the development of better lipid formulations for their own application fields. Numerous innovative lipid particulate systems have been formulated in recent years. One particularly interesting system is Cubosome (1). Cubosome refers to a submicron-sized dispersed lipid particle of the bicontinuous cubic liquid-crystalline phases in an aqueous environment. A great number of studies have been performed to investigate the structure (2,3) and the mathematical description of Cubosome particles (4,5). One of the main application fields for Cubosome is drug delivery (6,7). Cubosomes have distinctly different characteristics from other conventional lipid-particulate systems including liposomes and lipid emulsions. The interior of the particles is considered the hydrated cubic phase, which contains hydrophilic water channels, the hydrophobic hydrocarbon chain region, and the interfacial headgroup region (6). This somewhat complex internal structure is an ideal setting for many drugs of hydrophobic, hydrophilic, and amphiphilic nature.