title: Para-acyl-calix-arene based solid lipid nanoparticles (SLNs): a detailed study of preparation and stability parameters.
abstract: The preparation and stability parameters of para-acyl-calix[4]arene based solid lipid nanoparticles (SLNs) have been investigated. Atomic force microscopy (AFM) and photon correlation spectroscopy (PCS) show a mean particle size of 130 nm. In terms of preparation parameters, using the solvent displacement method, the nature and the volume of the organic solvent, the concentration of the amphiphile and the presence of a co-surfactant in the organic phase have been shown to affect significantly the size of the produced SLNs. In contrast, the stirring speed, the viscosity and the acidity of the aqueous phase and the amphiphile hydrophobic chain length have been shown to have no effect. In terms of stability parameters, the ionic strength has been shown to affect the short-time SLN stability depending on both the anion and the cation studied, with sodium sulphate causing precipitation. Ultrasonic, ultraviolet or microwave treatments of the SLN suspensions have no effect on the size of the SLNs. The study of the effects of short time thermal treatment revealed that the SLNs are not affected by one freezing-defreezing cycle and are stable at 100 degrees C in suspension. It is difficult to reconstitute the SLN suspensions after freeze-drying. Finally, the temporal stability of these suspensions in water has been shown to be superior to 1 year. The long-term temporal stability of suspensions stored in saline solution has been investigated. It has been demonstrated that the most destabilising effects arise from the presence in the storage suspension of sulphate ions.1H NMR, X-ray powder diffraction (XPD) and AFM have also been carried out on the calix-arene based SLNs and demonstrate the presence of a semi-organised matrix structure for the SLNs.
authors.affiliation: Institut de Biologie et Chimie des Protéines, CNRS UMR 5086, 7 Passage du Vercors, F-69367 Lyon Cedex 07, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Shahgaldian
authors.forename: Eric
authors.initials: E
authors.lastname: Da Silva
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Coleman
authors.forename: Beth
authors.initials: B
authors.lastname: Rather
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zaworotko
mesh_terms: D047250:Calixarenes; D003460:Crystallization; D004337:Drug Carriers / Q000737:chemistry* / Q000528:radiation effects; D004355:Drug Stability; D005227:Fatty Acids / Q000737:chemistry* / Q000528:radiation effects; D005612:Freeze Drying; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D008863:Microspheres; D008872:Microwaves; D036103:Nanotechnology; D009994:Osmolar Concentration; D010316:Particle Size; D010636:Phenols / Q000737:chemistry* / Q000528:radiation effects; D012997:Solvents; D013501:Surface-Active Agents; D013696:Temperature; D014465:Ultrasonics; D014466:Ultraviolet Rays; D014783:Viscosity; D014961:X-Ray Diffraction
chemical_list: D004337:Drug Carriers; D005227:Fatty Acids; D010636:Phenols; D012997:Solvents; D013501:Surface-Active Agents; C121325:calix(4)arene; D047250:Calixarenes