SAXS characterization of nanostructured systems for nifedipine nasal administration

Full text: Nifedipine drug used for hypertension control. However, due to its low bioavailability after oral administration it has been suggested the development of a stimuli-sensitive drug delivery system for nifedipine nasal administration. Systems composted by surfactant, oil and water can form a range of aggregates, as microemulsions (MEs) and liquid crystals (LCs). Therefore, the purpose of this study was to develop and evaluate the LC phase behavior of nifedipine formulations. The systems were composed of procetyl AWS® (surfactant), oleic acid (oil phase) and phosphate buffer (aqueous phase - AP) in different proportions and were characterized by Polarized light microscopy (PLM) and Small Angle X-ray Scattering (SAXS) at bean line 1 of Brazilian Synchrotron Light Laboratory (LNLS). The results showed that the systems are isotropic and with the increase of water content, they exhibited transition to anisotropic systems. There were observed wide peaks typical of micellar structures for isotropic systems. Samples with higher AP content exhibited the appearance of new peaks, indicating the beginning of phase transition to lamellar structures. The presented results showed that this systems have a great potential for NF nasal administration due to a possible mucoadhesion. Being structured systems they can promote a drug controlled release. (author)