Microwave-assisted formulation of solid lipid nanoparticles loaded with non-steroidal anti-inflammatory drugs.

Stearic acid-based solid lipid nanoparticles (SLNs) were prepared using the microwave assisted one-pot microemulsions procedure pioneered by our group. In this study, non-steroidal anti-inflammatory drugs (NSAIDs) including indomethacin, ketoprofen and nimesulide were selected as ideal "test" drugs, based on their poor water solubility. The model drugs were incorporated within the SLNs by the microwave-assisted procedure at the time of SLN production. The microwave-produced drug-loaded SLNs were evaluated in terms of their physicochemical characteristics, drug release behavior and their uptake into against A549 cell line (human lung epithelial cells). The microwave-produced drug-loaded SLNs had a small particle size distribution, negative zeta potential and high encapsulation efficiency. The drug release studies were consistent with a core-shell structure of SLNs (probably a drug-loaded shell) which results in biphasic drug release from the SLNs. The drug release kinetics suggested a good fit of the release data to the Makoid-Banakar model and was governed by Fickian diffusion. The drug-loaded SLNs showed concentration-dependent cytotoxicity and reduced IL-6 and IL-8 secretion in lipopolysaccharide-induced cells. All of the above findings suggest that the microwave-produced SLNs could be promising drug carriers of NSAIDs and will further facilitate their development for topical, oral and/or nasal administration.