title: Synthesis of composites of sodium oleate/Mg-Al-ascorbic acid-layered double hydroxides for drug delivery applications.
abstract: Mg-Al-ascorbic acid (ASA)-layered double hydroxides (ASA-LDHs) with Mg/Al=3 were synthesized by ion-exchange, coprecipitation and reconstruction methods. Composites with sodium oleate (SOA)/ASA-LDH were prepared by an ion-exchange method using various concentrations of SOA solutions. The (003) basal spacing of the ASA-LDHs changed from 0.76nm in the CO(3)-LDH to 0.78 and 0.86nm after intercalation of the ASA ions and these basal spacings are in good agreement with models based on the assumption as mono layers and double layers of ASA ions in the LDH interlayers, respectively. The amounts of ASA in the LDHs prepared by the reconstruction method were higher than those by the ion-exchange and coprecipitation methods. In the preparation of composites of SOA/ASA-LDH, an ion-exchange method was more suitable than a reconstruction method to cause surface sorption of the SOA molecules with maintaining intercalated ASA ions in the LDH interlayers. The acid-resistant properties of the composites of SOA/ASA-LDH were found to be much higher than for the pure ASA-LDH and mixture of CO(3)-LDH and ASA. The surfaces of the LDH particles in the composites are, thus, mostly covered with sorbed SOA molecules and they are good candidates as drug delivery materials for intestines through the stomach.
authors: Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, O-okayama, Meguro, Japan. ykameshi@cc.okayama-u.ac.jp
authors: Yoshikazu
authors: Y
authors: Kameshima
authors: Hirokazu
authors: H
authors: Sasaki
authors: Toshihiro
authors: T
authors: Isobe
authors: Akira
authors: A
authors: Nakajima
authors: Kiyoshi
authors: K
authors: Okada
mesh_terms: D017607:Aluminum Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000737:chemistry*; D002614:Chelating Agents / Q000138:chemical synthesis* / Q000737:chemistry; D003692:Delayed-Action Preparations; D016503:Drug Delivery Systems / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D017616:Magnesium Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D019301:Oleic Acid / Q000737:chemistry*; D033362:Powder Diffraction; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013997:Time Factors
chemical_list: D017607:Aluminum Compounds; D002614:Chelating Agents; D003692:Delayed-Action Preparations; D017616:Magnesium Compounds; D019301:Oleic Acid; C013173:osteum; D001205:Ascorbic Acid