Importance of solid lipid nanoparticles (SLN) in various administration routes and future perspectives

Solid lipid nanoparticles (SLN) have been reported to be an alternative system to emulsions, liposomes, microparticles and their polymeric counterparts for various application routes since the early 1990s due to their advantages. Various research groups have also increasingly focused on improving their stability in body fluids after administration by coating of particles with hydrophilic molecules such as poly(ethylene)glycol (PEG) derivatives. Altering surface characteristics by coating SLN with hydrophilic molecules improves plasma stability and biodistribution, and subsequent bioavailability of drugs entrapped. Their storage stability is also increased. This paper basicly reviews types of SLN, principles of drug loading and models of drug incorporation. The influence of PEG coating on particle size and surface characteristics is discussed followed by alteration in pharmacokinetics and bioavailability of drugs in order to target the site of action via SLN. The future direction of research and clinical implications of SLN is also considered

Formulation and characterization of solid lipid nanoparticles, nanostructured lipid carriers and nanoemulsion of lornoxicam for transdermal delivery

Solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC) and nanoemulsion (NE) of lornoxicam (LRX) were prepared for the treatment of painful and inflammatory conditions of skin. Compritol® 888 ATO, Lanette® O and oleic acid were used as solid and liquid lipids. Nanoparticles and nanoemulsion were obtained in a range 141 to 295 nm diameter (D50). 185 nm and 295 nm particle sizes were obtained for SLN of LRX based on Compritol® 888 ATO and Lanette® O when NLC displayed 185 nm and 266 nm particle sizes, respectively. Droplet size of drug NE was 166 nm. They were found physically stable at various temperatures for 6 months. Case I diffusional drug release was detected as the dominant mechanism indicating Fickian drug diffusion from nanoparticles and nanoemulsion. The highest rate of drug penetration through rat skin was obtained with NE followed by NLC, SLN and a gel formulation. Nanoformulations significantly increased drug penetration through rat skin compared to the gel (p < 0.05). Thus, SLN, NLC and NE of LRX can be suggested for relieving painful and inflammatory conditions of the skin by sustained drug release