Preparation, characterization, and evaluation of gatifloxacin loaded solid lipid nanoparticles as colloidal ocular drug delivery system

This article describes the preparation and characterization of solid lipid nanoparticles (SLNs) prepared with stearic acid (SLN-A) and a mixture of stearic acid and Compritol (SLN-B) as lipid matrix and poloxamer-188 as surfactant, using sodium taurocholate and ethanol as co-surfactant mixture, with a view to applying the SLN in topical ocular drug delivery. The SLNs were prepared by o/w microemulsion technique and characterized by time-resolved particle size analysis, polydispersity index, zeta(zeta)-potential, differential scanning calorimetry (DSC), IR-spectroscopy, and wide-angle X-ray diffractometry (WAXD). The results obtained in these studies were compared with SLN prepared with stearic acid alone. IR, WAXD, and DSC studies revealed low-crystalline SLN and were having positive zeta-potentials after three-months of storage. Results indicated mixed lipid-matrix produced SLN with low-crystallinity and smaller particle sizes and higher drug entrapment compared with SLN prepared with stearic acid alone, therefore SLN-B would be suitable for the preparation of nanosuspension. Nanosuspensions were subjected to rheological and physicochemical evaluation, in vitro drug release and ex vivo corneal permeation studies and their effect were evaluated on corneal hydration-level. SLN composed of stearic acid and compritol would prove to be a good ocular drug delivery system considering the smaller particle size, particle size stability, and physiologically tolerable components.