Preparation Of Chitosan@Ni-Ti-LDHs Composite And Its Controlled Release For Chitosan

Layered Double Hydroxides (LDHs) are a kind of brucite-like inorganic layered materials. In recent years, the LDHs have become one of the hot research topic as a kind of new drug delivery system. LDHs are typical anionic layered materials, they have some well properties such as ion exchangeable, exfoliation-reassembling and so on. Because of these, the methods to synthesize drug-LDHs nanohybrids can be intercalation assembly and exfoliation-reassembling. Carboxylated Chitsan(CS) is soluble chitsan is obtained by carboxylation of chitsan, it can bring down blood glucose, blood pressure, regulate the body’s environment, and so on. However, it have be a urgent problem in medical circles, it dissolve too fast in a body, can not have a long effect to a body. Due to stereo-hindrance effect of LDHs and interaction between drug and laminate, LDHs can controll drug’s releass well, and they are potential drug-controlled system.In this article, the precursor Ni-Ti-LDHs was synthesized by co-precipitation reaction method, and then prepare CS@LDHs nanohybrids by intercalation assembly and exfoliation-reassembling method, etc. The physico-chemical properties of the CS@LDHs nanohybrids were characterized by means of XRD, FT-IR, SEM, EDS and TG-DTG Nanohybrids release in phosphate buffered solution(PBS) with different pH, The change over time of concentration of CS detected by UV-vis, and then evaluating the sustained-release performance of LDHs. The results as follows combined with characterization and experimental:According to the results of XRD and SEM, the Ni-Ti-LDHs have obviously layered structures, and have "rose petals"-like layered strcture, however Ni-Ti-LDHs nanosheet have no obvious layered structrues, and have been exfoliated into one sigle or a few nanosheets layered structures successfully. According to the results of EDS and FT-IR, the substance of LDHs have nothing change before and after exfoliation. According to the results of TG-DTG, nanosheets’weight have a more loss than Ni-Ti-LDHs, because the Ni-Ti-LDHs namosheets will have a larger superficial area and more amount of hydroxyl and crystallization water than Ni-Ti-LDHs.The CS@LDHs nanohybrids were prepared successfully by intercalation method. According to the results of XRD and SEM, LDHs’interlayer spacing become smaller after intercalation reaction, and CS only load on the LDHs’ surface. Idicating small molecular and groups of CS intercalate into interlayer, and almostly load on outside surface. According to the results of EDS and FT-IR, the content of C element increase after intercalation reaction, and CS characteristic peak appear on nanohybrids’ FT-IR spectrogram, indicating CS have been loaded on LDHs. The results of releasing experiments are not very well, because CS load on outside surface of LDHs.The nanohybrids were prepared successfully by exfoliation-reassembling method, According to the results of XRD and SEM, the crystallinity of the nanohybrids are lower, but it is also the aggregation of the nanosheets, indicating CS and LDHs is reassembling into nanohybrids in a certain degree. It can be seen that the content of C element in the compound of CS have a obviously increasing on EDS and FT-IR spectrogram, And the characteristic peaks of CS appear on the nanohybrids’ FT-IR spectrogram, indicating CS have been loaded successfully on LDHs’ interlayer by exfoliation-reassembling method and the load increased greatly. The results of release test show that:CS was successfully inserted into the interlayer of LDHs, thus there is interaction between the CS and LDHs, CS can be controlled-release in the phosphate-buffer solution.