Recent Advances and Patents on Solid Lipid Nanoparticles

Abstract

Solid Lipid Nanoparticles (SLNs) have attracted increasing scientific and commercial attention as colloidal drug carriers during the last decade. They have emerged as a potential alternative compared to other colloidal systems like polymeric nanoparticles, liposomes and fat emulsions, as they have been claimed to combine their advantages but successfully overcome their drawbacks. SLN formulations are extensively developed and characterized for their in vitro and in vivo applications by various routes like parenteral, oral, pulmonary, ocular, and dermal. SLNs are being widely investigated as carriers for delivery of macromolecules like proteins, oligonucleotides and DNA. SLNs have already been taken up for medium and large scale production using two of its reported production methods. In fact, the first SLN based product has recently been introduced in the Poland market as a topically applied moisturizer. Newer methods for production of SLNs and their applications are being reported and patented. Nanostructured lipid carriers (NLC) are mixture of solid lipid and liquid lipid while Lipid Drug Conjugates (LDC) are water insoluble lipid carrier for loading of poorly lipid soluble drugs. These new generation of lipid nanoparticles have been claimed to overcome the shortcomings of SLNs. This article reviews the formulation, characterization, applications, and patents on the advances and research on SLNs, NLC and LDC.

Solid lipid nanoparticles for ocular drug delivery

“…Since then they have attracted scientists as a widely used, stable, non-toxic, and reliable particulate drug delivery vehicle. SLNs are structured as a solid lipid core in nanometer ranges accommodating the drug stabilized by a layer of surfactants (Sawant & Dodiya, 2008). SLNs have several advantages over other colloidal carriers, such as the possibility of controlling drug release, drug targeting, long-term stability, good drug loading (whether hydrophilic or lipophilic), absence of biotoxicity due to the use of physiological lipids, possibility of sterilization by autoclaving, and easy large scale production (Mehnert & Mäder, 2001).…”

“…They offer other advantages such as biodegradability, safety, low cost, simple production, and, most importantly, free dispersibility in aqueous media, enabling them to be formulated as modified eye drops (Sawant & Dodiya, 2008).…”

“…Limited drug loading capacity, possibility of drug expulsion during phase modifications, and high water content of SLNs aqueous dispersions (70-90%) have led to the introduction of NLCs (Mehnert & Mäder, 2001;Müller et al, 2002;Sawant & Dodiya, 2008). NLCs are produced by controlled addition of a spatially incompatible liquid lipid to the solid lipid component in order to accommodate a larger quantity of the drug and achieve a better release profile (Müller et al, 2002;Sawant & Dodiya, 2008).…”

“…glycerides) is added to the solid lipid can be regarded as imperfect NLCs. They induce a larger distance between the fatty acid chains of the main lipid core, which causes imperfections in the crystalline structure of the lipid where a very large amount of the drug can be incorporated (Sawant & Dodiya, 2008). For example, Jenning et al (2000) incorporated a medium length chain triglyceride oil in a matrix of a solid long chain glyceride, achieving higher payloads and controlled release properties (Jenning et al, 2000).…”

Solid Lipid Nanoparticles: Technological Developments and in Vivo Techniques to Evaluate Their Interaction with the Skin

“…2 shows that the potential sites for targeting nanoparticles include the surface of the skin, furrows, and hair follicles [Souto & Muller 2008]. A recent review by Baroli discusses nanoparticle penetration largely from the skin structure perspective debate of nanoparticle penetration [Baroli 2010, Sawant & Dodiya 2008, Medina et al 2007. The theory and practical aspects of percutaneous penetration of drugs, particulate material and contaminants have been covered in a number of excellent reference texts.…”