This paper reviewed our research progress in respects of th intercalation law of acetylsalicylic acid (ASP) with magnesium aluminate layered double hydroxide (LDH), the drug release mechanism and the tablet preparation effect of LDH-ASP system. We also discussed the propositions about the composite assembly rules, slow-release mechanism, and dosage form processing of the layered double hydroxide drug delivery system. Intercalation way and drug structure should be taken into consideration in assembly LDH-drugs system. The characteristic parameter of the composite LDH-drug reflected finely their loading efficiency and correlated definitely with drug release property. It had been found that the release rate and extent of intercalated drug was closely linked to the retarding status of LDH interlayer, which was dependent on the exchange mole ratio of n(drug) with n[HnPO4(3-n)-]. In addition, the grafting reaction and phase transformation degree of LDH layer was hinged on the acidity of solution. The slow-release function of the LDH-drug system could be improved significantly by compositing with dextran (DET). A sustained-release skeleton tablet was producted with DET-LDH-ASP drug delivery system and hydrophilic gel material HPMC, which could effectively overcome the "first pass effect" and " burst release problem" of LDH-drug oral agents. The slow-release effect of LDH drug delivery system could be ulteriorly improved in systemic circulation environments, attributed to the triple control of HPMC-DET-LDH, DET-LDH-drugs three-level supramolecular assembly and the special circulation in vivo. Key words: Layered double hydroxide, Supramolecular assembly, Release control, Slow controlled release drug delivery system

We report here the intracellular trafficking characteristics of a gene delivery system composed by magnetic layered double hydroxide/DNA (MLDH/DNA) hybrids to human gastric cancer cells (SGC-7901). Perls Staining of MLDH/DNA was done to examine the intracellular iron uptake and accumulation; confocal microscopy and transmission electron microscopy were evaluated the cellular internalization feature of the MLDH/DNA system. We have indicated that the MLDH/DNA hybrids are able to enter into the nucleus within 2 h of incubation, displaying a prospect for application in targeted gene delivery.

This paper studied the cytotoxicity of the dextran-magnetic layered double hydroxide-fluorouracil targeted liposomes ( DET-MLDH-FU liposomes, DMFL ) by MTT method against human ovarian adenocarcinoma cancer cells ( SKOV3 )in vitro. The results shown that the cellular inhibition rate at 24 h increased with the increasing of the fluorouracil concentration in DMFL, DET-MLDH-FU ( DMF ), fluorouracil-loaded liposomes ( FUL ) and free fluorouracil ( FU ). The order of inhibition rate was DMFL, DMF, FUL and FU at same concentration and intervention time. The IC50values of DMFL, DMF, FUL and FU were 14.39, 25.47, 34.39, 48.71 ( μgmL-1), respectively. The results of cytotoxicity experiment proved that the DMFL was superior than other preparations of fluorouracil.

In this paper, we synthesized a CdHgTe type water-soluble quantum dots, combined in the next time with the drug delivery system "dextran - magnetic layered double hydroxide - fluorouracil" (DMF), built a new nanostructures platform QD@DMF for blending the fluorescent probe function of quantum dot together with the magnetic targeting curative effect of the DMF system. The Fluorescence spectrophotometer, Ultraviolet spectrophotometer, TEM and XRD were used to characterize the luminescent properties, particle morphology and phase characteristics of the QD@DMF samples. The experiments on cell imaging were carried out by laser con-focal scan microscopy technique. Results showed that the CdHgTe QDs could be successfully grafted onto the surface of the DMF system through electrostatic coupling, forming a special structure based on magnetic layered double hydroxide with a near-infrared emission wavelength in 575~780 nm. Compared with QDs, the QD@DMF composite could significantly improve the cell imaging effect, the label intensity increased with the magnetic field intensity and obeyed the linear relationship Dmean = 1.760+0.013B. The fluorescent magnetic nanoparticles maintained not only the super-paramagnetic of DMF but also the photoluminescence properties of the QDs, implicating that the QD@DMF composite may be an effective multifunction tool for optical bio-imaging and magnetic targeted therapy.

The purpose of this paper is to prepare and evaluate a gene delivery system resulted from the intercalation of DNA with magnetic layered double hydroxide (MLDH). The structure and property of the MLDH/DNA hybrids were studied using XRD, FTIR and TG characterization. The cytotoxicity and protection effect of MLDH were evaluated by MTT assay and gel electrophoresis assay. MLDH exhibited lower cytotoxicity than other inorganic nanoparticles. Under physiological conditions, MLDH could protect DNA from enzymatic degradation. Our results confirmed that MLDH can be used safely and effectively as non-viral vectors for gene targeting therapy in form of MLDH/DNA composite.