pH-sensitive sodium alginate/calcined hydrotalcite hybrid beads for controlled release of diclofenac sodium.
OBJECTIVE
The aim of this study was to prepare pH-sensitive sodium alginate/calcined hydrotalcite (SA/CHT) hybrid bead with improved the burst release effect of the drug. materials and methods: A series of pH-sensitive SA/CHT hybrid beads were prepared by using Ca²⁺ cross-linking in the presence of diclofenac sodium (DS) and SA. The structure and drug loading of the beads were characterized by Fourier transform infrared spectroscopy and X-ray diffraction. The swelling and the drug release of the fabricated beads were investigated by the pH of test medium and CHT content.


RESULTS
The formed positively charged hydrotalcite layers were adsorbed on the negatively charged SA polymer chains through electrostatic interaction and act as inorganic cross-linkers in the three-dimensional network. Compared to pure SA beads, the incorporation of CHT enhanced the drug encapsulation efficiency, improved the swelling behaviors and slowed the drug release from the hybrid beads.


CONCLUSIONS
The electrostatic interaction between hydrotalcite and SA has restricted the movability of the SA polymer chains, and then slowed down swelling and dissolution rates in aqueous solutions. The results provided a simple method to moderate drug release and matrix degradation of the SA beads.
Center of Eco-material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, China.
Shuibo
S
Hua
Huixia
H
Yang
Qiong
Q
Li
Junping
J
Zhang
Aiqin
A
Wang
D000464:Alginates / Q000737:chemistry*; D000536:Aluminum Hydroxide / Q000737:chemistry*; D000863:Antacids / Q000737:chemistry*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000493:pharmacokinetics*; D003692:Delayed-Action Preparations; D004008:Diclofenac / Q000493:pharmacokinetics*; D016503:Drug Delivery Systems; D006863:Hydrogen-Ion Concentration; D008276:Magnesium Hydroxide / Q000737:chemistry*; D008863:Microspheres; D010316:Particle Size; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D055672:Static Electricity; D014961:X-Ray Diffraction / Q000379:methods
D000464:Alginates; D000863:Antacids; D000894:Anti-Inflammatory Agents, Non-Steroidal; D003692:Delayed-Action Preparations; D004008:Diclofenac; C010467:hydrotalcite; D000536:Aluminum Hydroxide; D008276:Magnesium Hydroxide