Abstract
The present research focuses on the development and characterization of a delivery system for ifosfamide to enhance its stability and sustaining in vitro release. Solid lipid nanoparticles (SLNs) of ifosfamide were developed by double emulsion solvent evaporation technique using glyceryl monooleate and chitosan. The chitosan present in the delivery system was cross-linked using sodium tripolyphosphate. The effect of chamber pressure during lyophilization of emulsions was studied by lyophilizing the emulsion at low pressure (high vacuum) and high pressure (low vacuum). Two products having distinct morphologies were obtained as a result of lyophilizing emulsion under different vacuum conditions. They were named as matrix system and nanoparticles and both these systems were characterized. The particle size and surface charge of the delivery systems were determined using a zetasizer. The surface morphology was analyzed using scanning electron microscopy (SEM). Moisture content and weight loss on heating were assessed using Karl Fischer titrimetry and thermogravimetric analysis, respectively. The physical state of the drug in the particles was analyzed using differential scanning calorimeter (DSC) and X-ray diffractometer (XRD). Fourier Transform Infrared Spectroscopy (FTIR) was used to evaluate the cross-linking of chitosan in the delivery system. In vitro drug release at pH 7.4 and pH 6.8 was carried out and samples were analyzed using High Performance Liquid Chromatograpy (HPLC). The degradation of ifosfamide in solution and in the delivery systems at pH 2.5 was evaluated using and Liquid Chromatography/Mass Spectroscopy (LC/MS). Cellular permeability studies of ifosfamide solution and the delivery systems were performed using Caco-2 cells. Subcellular localization studies using rhodamine loaded nanoparticles were performed using Caco-2 cells. Different chamber pressures during lyophilization produced products having different morphology and moisture content. The drug in the delivery systems was found to exist in a non-crystalline state. Both the delivery systems showed high drug loading efficiency and were able to sustain the release of the drug in pH 7.4 as well as pH 6.8. The stability of ifosfamide in the delivery system was found to be better than free drug in acidic medium. Drug in solution and nanoparticles showed a significantly higher permeability from the apical to the basolateral side while no significant difference was observed in the case of matrix system. The nanoparticles were found to be localized in the lysosomes of the Caco-2 cells.