Solid State Characterization and Effect of PEG 20000 and Lecithin on Particle Size Reduction and Stability of Complexed Glibenclamide Nanocrystals

Aims: To formulate and characterize GLB-PEG-LEC NCs (lecithin complexed Glibenclamide nanocrystals) and to analyze the effect of PEG 20000 and lecithin on drug properties, particle size reduction and stability of GLB NCs.
Study Design: Precipitated (GLB-PEG) and complexed nanocrystals (GLB-PEG-LEC) of glibenclamide were characterized for particle size, size distribution, zeta potential and stability assessment using photon correlation spectroscopy. The crystallinity was analyzed by X-ray powder diffraction spectroscopy and differential scanning calorimetry. The chemical stability was assessed by means of infrared spectroscopy and surface morphology by scanning electron microscopy.
Place and Duration of Study: Asian Institute of Medicine Science and Technology, Malaysia, between May 2102 and June 2013.
Methodology: GLB-PEG NCs were prepared by precipitation technique using PEG 20000 and complexed by soybean lecithin. The effect of lecithin in particle size reduction, change in crystallinity, stability and surface properties of NCs were analyzed and compared with pure glibenclamide (GLB) and precipitated NCs. The formulations were optimized and its stability was assessed during a 3 month period.
Results: Pure GLB exhibited an average particle size of 1551 nm. The average particle size of precipitated NCs was between 236 - 7000 nm, while that of complexed NCs was between 155 - 842 nm. The particle size of NC was found to decrease, whereas its zeta potential was found to increase after complexation. DSC studies showed no change in crystalline structure. PXRD studies proved that crystallinity was maintained in NCs. SEM analysis showed presence of spherical shape particles with a lipid coat on the surface after complexation. Stability studies revealed no change in particle size during 3 month period. FTIR studies showed the compatability of excipients with the drug.
Conclusion: These results show that lecithin complexed GLB NCs could be utilized as promising carriers in development of various formulations due to its high stability and decreased particle size.