ABSTRACT
In the last few years, various delivery technologies for biologically active moieties have evolved, and nanoscale delivery systems have been developed for many pharmaceutical and medical applications. Nanostructured lipid carriers are drug delivery systems that consist of a semi-crystallized lipid moiety with mean particle size ranging up to 100 nm and dispersed in an aqueous phase containing surface-acting agents. Nanostructured lipid carriers offer distinctive advantages over conventional carriers, like increase in drug loading capability, better entrapment efficiency, better solubility and stability, and improved bioavailability and half-life. Moreover, much better release in terms of longer sustainability and efficacious action of the drug can be achieved. Nanostructured lipids come under the category of lipid nanoparticles, and in an earlier developmental stage, comprised an O/W type of nanoemulsion by replacing liquid lipids with solid lipids, resulting in the formation of solid lipid nanoparticles. These solid lipid nanoparticles had the disadvantage of an unpredictable gelation tendency with polymeric transitions. This leads to the formation of nano lipid carriers. These nano lipid carriers consist of a mixture of solid and liquid lipids, which results in a reduced melting point due to the formation of unorganized solid matrices. This molecular transformation leads to higher drug loading capacity and better control over drug release. The major components for manufacturing nanostructured lipid carriers include lipids, i.e. a mixture of both solid and liquid lipids, along with emulsifying agents. The manufacturing techniques include high-shear homogenization and hot and cold high-shear homogenization. Bioactives can be encapsulated at different positions, such as a bioactive-enriched shell or core or matrix, and a combination is also possible.
