Structural and physicochemical aspects of drug release from layered double hydroxides and layered hydroxide salts.

R. ROJAS; Y. GARRO LINCK; S. CUFFINI; G. A. MONTI; C. E. GIACOMELLI

APPLIED CLAY SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 109 p. 119 - 126

0169-1317

Layered double hydroxides and Zn layered hydroxide salts present different physicochemical properties derived from their dissimilar structure and composition. In this work these aspects are studied to understand their different behavior as drug carriers. LDHs and LHSs intercalated with three different NSAIDs (Ibu, Nap and Ket) were obtained. The structure and bonding of the solids was determined by chemical analysis, PXRD, FT-IR and RMN. Also, the interfacial properties (potential zeta and hydrophillic/hydrophobic character) of the hybrids, as well as the drug release profiles were comparatively studied. The drugs were bonded by electrostatic interactions to LDH layers while coordinated bonding was produced in the case of LHSs, whose structure was different for ibuprofen containing hybrid and for those containing naproxen or ketoprofen. The different bonding, together with the higher anion density between LHS layers produced more chrystalline solids with larger basal spacings than those obtained for LDHs. The differences in structure, bonding and composition explained the surface charging behavior and the larger solubility of LHS layers explained their faster drug release in neutral media. Finally, the loose arrangement in the hybrids compared to that of the pure drug explained the solubility increase obtained in acid media.