Abstract:
Solid Lipid Nanoparticles (SLNs) are advanced colloidal drug delivery systems composed of biocompatible and biodegradable lipids, which remain solid at both room and body temperatures. Developed in the early 1990s as an alternative to liposomes and polymeric nanoparticles, SLNs have gained considerable attention due to their potential to improve drug bioavailability, stability, and controlled release. SLNs typically consist of solid lipids (such as glyceryl behenate or stearic acid), emulsifiers (e.g., polysorbates, lecithins), and an aqueous phase. Drugs, particularly lipophilic ones, are incorporated into the solid lipid matrix, which provides protection against enzymatic degradation and environmental factors. Various production methods such as high-pressure homogenization, ultrasonication, microemulsion techniques, and solvent evaporation are used to prepare SLNs. These influence particle size, encapsulation efficiency, and release kinetics. SLNs demonstrate a favorable physicochemical profile, including small particle size (typically 50–1000 nm), high drug-loading potential, and controlled drug release mechanisms. Additionally, their use of Generally Recognized As Safe (GRAS) materials supports their biocompatibility. Applications span across pharmaceuticals, cosmetics, and nutraceuticals, including oral, topical, and parenteral drug delivery. However, limitations such as drug expulsion, polymorphic transitions, and relatively low drug loading have prompted the development of second-generation carriers like nanostructured lipid carriers (NLCs). SLNs represent a versatile platform with growing commercial and clinical interest. Future directions involve targeted delivery, stimuli-responsive formulations, and environmentally sustainable production techniques, positioning SLNs as a cornerstone in next-generation drug delivery technologies.
Keywords:
Solid lipid nanoparticles, methods of preparations, evaluations, applications.
