NLCs

NLCs, or nanostructured lipid carriers, are a class of lipid-based nanoparticles designed to improve the solubility, stability, and controlled release of therapeutic compounds. They consist of a solid lipid matrix in which a portion of liquid lipid is dispersed, creating a less-ordered crystalline structure with imperfections that provide spaces to accommodate drug molecules. This composition supports higher drug loading and reduces the risk of drug expulsion during storage compared with solid lipid nanoparticles (SLNs).

The lipid matrix is typically formed from biocompatible solid lipids such as glyceryl behenate or glyceryl palmitate, combined with liquid lipids like medium-chain triglycerides. Surfactants and co-surfactants stabilize the colloidal dispersion and prevent aggregation. NLCs are prepared by methods including high-pressure homogenization, microemulsion techniques, solvent emulsification-evaporation, and ultrasonication. Particle sizes usually range from tens to several hundreds of nanometers, with polydispersity index indicating uniformity and zeta potential reflecting colloidal stability.

NLCs can be formulated for various administration routes, including oral, dermal, transdermal, ocular, and parenteral delivery, and they can enhance the bioavailability of poorly soluble drugs, enable sustained release, and improve tissue targeting in some cases. Applications span pharmaceuticals, nutraceuticals, and vaccines, with ongoing research in cancer therapy, dermatology, and gene delivery.

Limitations include challenges in manufacturing scale-up, batch-to-batch reproducibility, potential surfactant-related toxicity, and the need for robust stability data and regulatory guidance. NLCs are part of the broader family of lipid-based nanocarriers, alongside SLNs and other nanoparticle systems.