The solid lipid nanoparticles (SLNs) usually consists of active drug molecules along with solid lipids,
surfactants, and/or co-surfactants. They possess some potential features such as nano-size, surface with a free
functional group to attach ligands, and as well they prove safe homing for both lipophilic as well as hydrophilic
molecules. As far as synthesis is concerned, SLNs can be prepared by employing various techniques viz., homogenization
techniques (e.g., high-pressure, high-speed, cold, or hot homogenization), spray drying technique, ultrasonication,
solvent emulsification, double emulsion technique, etc. Apart from this, they are characterized by
different methods for determining various parameters like particle-size, polydispersity-index, surface morphology,
DSC, XRD, etc. SLNs show good stability as well as the ability for surface tailoring with the specific ligand,
which makes them a suitable candidate in the therapy of numerous illnesses, especially in the targeting of the
cancers. In spite of this, SLNs have witnessed their application via various routes e.g., oral, parenteral, topical,
pulmonary, rectal routes, etc. Eventually, SLNs have also shown great potential for delivery of gene/DNA, vaccines,
as well as in cosmeceuticals. Hence, SLNs have emerged as a promising nanomaterial for efficient delivery
of various Active Pharmaceutical Ingredients (APIs).