Preparation of Glycy- l-Tyrosine intercalated layered double hydroxide film and its in vitro release behavior

This paper describes the preparation of films of peptide (Glycy- l-Tyrosine, denoted as GlyTyr) intercalated layered double hydroxide (LDH) and its release performances. GlyTyr has been intercalated into a magnesium–aluminum LDH, and the resulting film was fabricated by solvent evaporation method in order to exploit new formulation in drug carrier especially used in skin medicament. Based on the results of XRD, FT-IR, FT-IR-ATR, UV–vis, 13C NMR, ICP and elemental analysis, it was found that GlyTyr has been successfully intercalated into LDH gallery. TG/DTA, in situ FT-IR, in situ XRD and polarimetry indicate that the chemical stability of GlyTyr was enhanced significantly in the confined region of LDH galleries compared with its pristine form. SEM reveals that the film thickness is about 12.6 μm with c-orientation of LDH platelets ( ab plane parallel to the substrate). In vitro release tests of the GlyTyr-LDH film in pH 7.4 phosphate buffered saline (PBS) showed that no burst release phenomenon occurred at the beginning stage and a high release ratio of GlyTyr (91%) was obtained, exhibiting controlled release behavior. Furthermore, the parabolic diffusion model was used to simulate the release kinetics of GlyTyr from the LDH carrier, indicating that the external surface diffusion or the intraparticle diffusion via ion-exchange is the rate-determining step in the release process. Therefore, this work demonstrates that Mg/Al-LDH is an effective inorganic matrix for the peptide storage and controlled delivery at the required time.