A brief review on solid lipid nanoparticles: part and parcel of contemporary drug delivery systems

Drug delivery technology has a wide spectrum, which is continuously being upgraded at a stupendous speed. Different fabricated nanoparticles and drugs possessing low solubility and poor pharmacokinetic profiles are the two major substances extensively delivered to target sites. Among the colloidal carriers, nanolipid dispersions (liposomes, deformable liposomes, virosomes, ethosomes, and solid lipid nanoparticles) are ideal delivery systems with the advantages of biodegradation and nontoxicity. Among them, nano-structured lipid carriers and solid lipid nanoparticles (SLNs) are dominant, which can be modified to exhibit various advantages, compared to liposomes and polymeric nanoparticles. Nano-structured lipid carriers and SLNs are non-biotoxic since they are biodegradable. Besides, they are highly stable. Their (nano-structured lipid carriers and SLNs) morphology, structural characteristics, ingredients used for preparation, techniques for their production, and characterization using various methods are discussed in this review. Also, although nano-structured lipid carriers and SLNs are based on lipids and surfactants, the effect of these two matrixes to build excipients is also discussed together with their pharmacological significance with novel theranostic approaches, stability and storage.

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or continue reading here: A brief review on solid lipid nanoparticles: part and parcel of contemporary drug delivery systems – Yongtao Duan, Abhishek Dhar, Chetan Patel, Mehul Khimani, Swarnali Neogi, Prolay Sharma, Nadavala Siva Kumar and Rohit L. Vekariya – DOI: 10.1039/D0RA03491F (Review Article) RSC Adv., 2020, 10, 26777-26791

Principle of lipid nanoparticle formulation

General ingredients

SLNs are comprised of a phospholipid-coated solid hydrophobic core matrix (containing the hydrophobic tails of the phospholipid section) (Fig. 2). Also, SLNs consist mainly of solid lipid(s), emulsifiers together with APIs such as drugs, genes, DNA, plasmid, and proteins. The lipids utilized in the formation of SLNs are surfactant stabilized, and thus solid at both physiological and room temperature. Depending on their structure, lipids are mainly divided into fatty acids, fatty esters, fatty alcohols, triglycerides, and partial glycerides. Ionic and nonionic polymers (Pluronic® such as F-68 and F127), surfactants, and organic salts are used as emulsifiers. However, their physicochemical characteristics also affect the behavior of the corresponding SLNs in both in vivo and in vitro release. The formation of colloidal nanoparticles depends on the interfacial tension and surface tension between two liquids. Thus, the main principle for the formation of solid lipid nanoparticles is the adhesive forces between two liquids. Normally, the interfacial tension between two liquids is less than their surface tension because of the weaker adhesive forces compared to that with gas. Molecules at the interface constitute surface free energy of interfacial tension, while they undergo agitation and form a spherical system to minimize the surface free energy.

From the publication “A brief review on solid lipid nanoparticles: part and parcel of contemporary drug delivery systems” the interesting Table 2 SLN formulations reported by different researchers