title: Using solution X-ray scattering to determine the high-resolution structure and morphology of PEGylated liposomal doxorubicin nanodrugs.
abstract: BACKGROUND
  Among nanodrugs, PEGylated nanoliposomes loaded with an active agent are of major importance. In this paper we studied the structures and morphology of PEGylated nanoliposomes before and after remote loading with doxorubicin.
  
  
  METHODS
  High-resolution structures were obtained by solution X-ray scattering combined with our advanced analysis tools. We studied the PEGylated liposomal doxorubicin (PLD) product Doxil(®), and its generics, where remote doxorubicin loading is performed by a gradient of ammonium sulfate, and LC100, a novel PLD under development, where remote loading was done by a gradient of ammonium methanesulfonate. The PLD structures were compared with drug-free nanoliposomes having identical composition.
  
  
  RESULTS
  We determined the membrane electron density profiles of the empty and loaded PLDs, the thickness and density of the PEG layers, and the structure of the drug inside the liposomes.
  
  
  CONCLUSIONS
  The liposomal membranes had the same structure for both ammonium salts. We found that the drug formed crystals inside PLDs loaded by ammonium sulfate, whereas it had an amorphous morphology in the PLD loaded by ammonium methanesulfonate. The variations of the drug's structural parameters between the generics of Doxil(®) are similar to the variations between batches of the same product, suggesting that all these products were structurally similar.
  
  
  CONCLUSIONS
  This paper demonstrates that solution X-ray scattering, when combined with our powerful analysis tools, can determine the high-resolution structure of complex non-crystallized nanoparticle dispersions used in nanomedicine, thereby providing useful physical insights into their functions.
authors.affiliation: Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Y
authors.initials: Y
authors.lastname: Schilt
authors.affiliation: Laboratory of Membrane and Liposome Research, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel; The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Berman
authors.affiliation: Laboratory of Membrane and Liposome Research, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.
authors.forename: X
authors.initials: X
authors.lastname: Wei
authors.affiliation: Laboratory of Membrane and Liposome Research, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel; The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel. Electronic address: chezyb@gmail.com.
authors.forename: Y
authors.initials: Y
authors.lastname: Barenholz
authors.affiliation: Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel. Electronic address: uri.raviv@mail.huji.ac.il.
authors.forename: U
authors.initials: U
authors.lastname: Raviv
mesh_terms: D004317:Doxorubicin / Q000031:analogs & derivatives* / Q000737:chemistry; D053758:Nanoparticles; D011092:Polyethylene Glycols / Q000737:chemistry; D012542:Scattering, Radiation; D012996:Solutions; D014965:X-Rays
chemical_list: D012996:Solutions; C506643:liposomal doxorubicin; D011092:Polyethylene Glycols; D004317:Doxorubicin
keywords: Drug delivery; Generic drugs; Liposomal doxorubicin; PEGylated liposomes; SAXS; WAXS