Spectroscopic characterization and general features of piroxicam encapsulated in nanostructured lipid carriers

A detailed and unique spectroscopic study was developed to understand the interaction between an active principle and a lipid based-drug delivery system. Nanostructured lipid carrier (NLCs) loaded with piroxicam (PX) was prepared via the microemulsion method. The resulting general characterization parameters were optimal, spherical, monodisperse, and stable nanoparticles with particle size less than 200 nm were obtained. Spectroscopic techniques allowed us not only to estimate the drug location inside the lipid nanoparticles but also to determine that the drug incorporation into the carrier system is not complete. Some PX molecules are incorporated inside the lipid core, far from the nanoparticle surface and other drug molecules remain outside the nanocarrier, possibly inside surfactant micelles. Moreover, this study made it possible to fully characterize the spectroscopical behavior of the three PX species. The obtained results showed that in both cases, inside and outside the NLCs, the predominant PX structure seems to be the enolic one.