Synthesis and Characterization of Camptothecin Intercalated into Mg/Al Layered Double Hydroxide

The intercalation of camptothecin (CPT) into a layered inorganic host, Mg-Al layered double hydroxide (LDH), was carried out using a coprecipitation method to obtain CPT-LDH nanohybrids. It was found that the intercalated amounts (A(in)) of CPT-LDH nanohybrids were remarkably dependent on the molar ratios (R-C/M) of CPT to metal ions in raw materials. The A(in) value increases with the R-C/M value increasing. According to the gallery heights of CPT-LDH and sizes of CPT molecule, a probably morphology of CPT molecules in the gallery of LDH was suggested that the horizontal-arranged monolayer and vertical-arranged bilayer of CPT molecules coexisted in the interlayer region of LDH. An interesting result was found that the gallery height corresponding to the bilayer of CPT-LDH sample with a high A(in) value was remarkably lower than that with low A(in) value. The in vitro CPT release examinations from the nanohybrids showed that the CPT-LDH nanohybrids were a potential drug controlled release system. The kinetic analysis showed that the release kinetics of CPT from the nanohybrids obeyed the pseudo-first order kinetic model and the diffusion of CPT through the LDH particle of CPT played an important role in controlling the drug release rate.