title: Multifractal Characterization of Pharmaceutical Hot-Melt Extrudates.
abstract: Multifractal geometry has become a powerful tool to describe complex structures in many fields. Our first aim was to combine imaging and multifractal analysis to better understand the microstructure of pharmaceutical extrudates. A second objective was to study erosion/dispersion behavior of the formulations because it would condition release of any drug.
  
  
  
  Different formulations containing a lipid, a polymer and different silica based inorganic carriers were produced by hot-melt extrusion at various screw speeds. Multifractal analysis was based on scanning electron microscopy/energy dispersive X-Ray spectroscopy images. This microstructural analysis was complemented with dynamic optical imaging of formulation erosion/dispersion behavior.
  
  
  
  Multifractal analysis indicated that inorganic carrier type and concentration as well as the screw speed affected the microstructure of the extrudates. The aqueous erosion/dispersion study showed that only the type and concentration of inorganic carrier were important.
  
  
  
  The use of microstructural and dispersion analysis appeared to be complementary to better characterize and understand complex formulations obtained by hot-melt extrusion.
authors.affiliation: Institute of Pharmaceutical Technology, University of Applied Sciences and Arts Northwestern Switzerland, Gründenstrasse 40, 4132, Muttenz, Switzerland.|Institute of Pharmaceutical Technology, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland.
authors.forename: Camille
authors.initials: C
authors.lastname: Adler
authors.affiliation: DSM Nutritional Products Ltd., R&D Center Formulation & Application, P.O. Box 2676, 4002, Basel, Switzerland.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Teleki
authors.affiliation: Institute of Pharmaceutical Technology, University of Applied Sciences and Arts Northwestern Switzerland, Gründenstrasse 40, 4132, Muttenz, Switzerland. martin.kuentz@fhnw.ch.
authors.forename: Martin
authors.initials: M
authors.lastname: Kuentz
mesh_terms: D002152:Calorimetry, Differential Scanning / Q000379:methods; D002626:Chemistry, Pharmaceutical / Q000379:methods; D004337:Drug Carriers / Q000737:chemistry; D006358:Hot Temperature; D008055:Lipids / Q000737:chemistry; D008855:Microscopy, Electron, Scanning / Q000379:methods; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D004337:Drug Carriers; D008055:Lipids; D004364:Pharmaceutical Preparations; D011108:Polymers; D012822:Silicon Dioxide
keywords: dispersion; hot-melt extrusion; inorganic carrier; multifractal; scanning electron microscopy