Maad Rayan Publishing Company Biomedical Research Bulletin 2980-9924 2 3 2024 09 30 Basics of Solid Lipid Nanoparticles Formulation 133 139 10.34172/biomedrb.2024.20 EN Maryam Hasan Zadeh Navroodi https://orcid.org/0009-0003-5152-287X Morteza Marashi Faezeh Talaei Mohaddeseh Argha Soheila Mokari Javad Shokri Shalen Kumar Tooba Gholikhani https://orcid.org/0000-0002-9714-7257 REVIEW 10.34172/biomedrb.2024.20 2024 08 14 2024 09 15 Lipid nanoparticles (LNPs) have captured significant attention in the past few years and are widely used. Nanostructured lipid carriers (NLCs) and solid lipid nanoparticles (SLNs) are two lipid-based NPs with potential applications in research, drug delivery, cosmetics, and other fields. By modifying the size range, they can be used through different routes. Physically stable and targeted SLNs with good release profiles have been designed to overcome the limitations of emulsions and liposomes. NLCs are modified SLNs that enhance loading capacity and stability. Regardless of the preparation method, an initial emulsion is essential. The quality of the initial emulsion can affect the desired size range. This study highlights the critical features required to prepare the initial emulsion wisely and rationally.