Targeted Drug Delivery for Cardiovascular and Cerebrovascular Diseases.

Cardiovascular and cerebrovascular diseases (CCVD) are a major and increasing health burden worldwide. Although treatments have been made a certain progress, the development of novel therapies for patients remains a major research object. There are a lot of drugs against CCVD, but most of them lack tissue specificity with a short half-life, which seriously limits their extensive clinical application. Utilization of some pathophysiological changes caused by CCVD, targeted drug distribution in CCVD patients could be achieved. The current review aims to capture various drug delivery systems transporting drug specifically to vascular disease, including passive, active and physicochemical targeted delivery carriers. Their design strategies and mechanisms are described in detail. The present limitations and future perspective are also discussed.

PEGylated long circulating nanostructured lipid carriers for Amoitone B: preparation, cytotoxicity and intracellular uptake.

Amoitone B is a newly synthesized derivative of antitumor drug cytosporone B, which exhibits excellent anticancer activity in vivo. Nevertheless, the water-insolubility and short biological half-life limit its further development. In the present study, polyethylene glycol-modified, Amoitone B-loaded long circulating nanostructured lipid carriers (AmB-PEG-NLC) were prepared by the emulsion-evaporation and low temperature-solidification method. The in vitro antitumor activity and intracellular uptake of AmB-PEG-NLC in the human colon cancer SW620 cells and liver cancer HepG2 cells were evaluated in detail. MTT assay was employed to investigate the inhibition effect on cellular viability. Propidium iodide and DAPI staining were performed to visually examine the fluorescent morphology changes of the cells incubated with AmB-PEG-NLC. Flow cytometry was utilized to determine the influence of AmB-PEG-NLC on apoptosis of SW620. The intracellular uptake was observed by rhodamine B, a fluorescent maker. Cytotoxicity assay, observation of morphological changes and apoptosis examination revealed that AmB-PEG-NLC could markedly enhance the cytotoxicity of AmB against cancer cell compared to AmB solution and AmB-NLC. An increased uptake of PEG-NLC was obtained compared with NLC in SW620 cells, which might attribute to the effect of PEG. Based on these results, AmB-PEG-NLC could be a promising delivery system for AmB with effective cancer therapy.

Research on the in vitro anticancer activity and in vivo tissue distribution of Amoitone B nanocrystals.

Amoitone B, a natural agonist to Nur77, is a promising anticancer drug. However, its application is seriously restricted due to the water-insolubility and short biological half-life. Amoitone B nanocrystals (AmB-NC) were formulated by microfluidization method to overcome the above obstacles. This study aims to evaluate the cytotoxicity and tissue distribution of AmB-NC. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay revealed the improved in vitro antitumor activity of AmB-NC against stomach, colon, liver and lung cancer cells compared with Amoitone B solution. Meanwhile, observation of morphological changes, cell cycle and apoptosis examination using flow cytometry exhibited that AmB-NC could induce G1 cycle arrest and markedly enhance the apoptosis of human gastric cancer BGC-823 cell line. Tissue distribution study demonstrated that AmB-NC had a higher distribution in liver and lung, which was helpful for relevant cancer treatment. In conclusion, AmB-NC could be a potential delivery system for treatment of human cancer.

In vitro and in vivo study of Gal-OS self-assembled nanoparticles for liver-targeting delivery of doxorubicin.

A liver-targeting drug delivery system for doxorubicin (DOX), that is, DOX-loaded self-assembled nanoparticles based on galactosylated O-carboxymethyl chitosan-graft-stearic acid conjugates (Gal-OS/DOX), has been prepared. The objective of the present study was to investigate the preparation, in vitro release, in vivo pharmacokinetics, and tissue distribution of Gal-OS/DOX nanoparticles. The drug-loaded nanoparticles were spherical in shape with mean size of 181.9 nm. In vitro release profiles indicated that the release of DOX from Gal-OS/DOX nanoparticles behaved with a sustained and pH-dependent drug release. Pharmacokinetics study revealed Gal-OS/DOX nanoparticles exhibited a higher AUC value and a prolonged residence time of drug in the blood circulation than those of DOX solution. Furthermore, Gal-OS/DOX nanoparticles increased the uptake of DOX in liver and spleen, but decreased uptake in heart, lung, and kidney in the tissue distribution study. These results suggested that the Gal-OS/DOX nanoparticles could prolong blood circulation time, enhance the liver accumulation, and reduce the side effect especially the cardiotoxicity of DOX. In conclusion, Gal-OS/DOX nanoparticles could be a promising drug delivery system for liver cancer therapy.

Preparation, characterization and pharmacokinetics of Amoitone B-loaded long circulating nanostructured lipid carriers.

Amoitone B, chemically synthesized as the derivative of Cytosporone B, is a powerful agonist for Nur77 receptor. It has outstanding anticancer activity in vivo. However, the water-insolubility and short biological half-life lead to poor bioavailability, which limits its application. The aim of this study was to develop polyethylene glycol-coated Amoitone B-loaded nanostructured lipid carriers (AmB-PEG-NLC) for parenteral delivery of Amoitone B to prolong drug circulation time in body and enhance the bioavailability. AmB-PEG-NLC were prepared by emulsion-evaporation and low temperature-solidification method, while Amoitone B-loaded NLC (AmB-NLC) were also prepared as control. The characteristics of AmB-PEG-NLC and AmB-NLC such as particle size, zeta potential, entrapment efficiency and drug loading were investigated in detail. The mean particle size was about 200 nm and the zeta potential value was about -15 mV. The X-ray diffraction analysis demonstrated that Amoitone B was not in crystalline state in NLC (AmB-PEG-NLC and AmB-NLC). Drug release pattern with burst release initially and prolonged release afterwards was obtained in vitro for AmB-PEG-NLC. Furthermore, AmB-PEG-NLC exhibited prolonged MRT (mean residence time) and higher AUC (area under drug concentration-time curve) compared with AmB-NLC as well as Amoitone B solution. These results indicated that AmB-PEG-NLC could be a promising delivery system for Amoitone B to prolong the circulation time in body and thus improve its bioavailability.

Folate-modified bexarotene-loaded bovine serum albumin nanoparticles as a promising tumor-targeting delivery system.

Bexarotene (BEX), a high-affinity agonist for retinoid X receptors (RXRs), shows apparent biological activities and distinct inhibitive efficacy in both cancer therapy and prevention. This study exploited a folate-decorated delivery of bexarotene-loaded bovine serum albumin nanoparticles, which could solubilize the poorly water-soluble drug and overcome the nonspecific targeting disadvantage. Bexarotene-loaded bovine serum albumin nanoparticles (BEX-BSANPs) were optimized by a desolvation technique, subsequently conjugated with folate by carbodiimide reaction. The resultant folate-modified bexarotene-loaded bovine serum albumin nanoparticles (FA-BEX-BSANPs) showed a spherical shape, with a diameter of 195.3 ± 5.6 nm, a zeta potential of -33.64 ± 1.97 mV, and 71.28 ± 1.93 µg folate was coupled per mg BSA. Differential scanning calorimetry and X-ray diffraction analysis confirmed the amorphous state of bexarotene in the folate-conjugates. The in vitro drug release of bexarotene presented a controlled and sustained release pattern. The in vitro cytotoxicity, cell apoptosis and cellular uptake experiments of the nanoparticles were performed by MTT assay, propidium iodide staining, fluorescence microscopy and flow cytometric analysis on A549 and MCF-7 cancer cells. Both the BEX-BSANPs and FA-BEX-BSANPs induced an enhanced cancer cell apoptotic effect in contrast to BEX solution. The cells showed an excellent binding for folate-modified nanoparticles. Especially, the interference effect on the cellular internalization process by an excess folic acid was relatively dramatic for the FR-positive MCF-7 cells in comparison to the modest change seen in the FR-negative A549 cell lines, indicating that the uptake was mediated by the folate receptors. Together these data suggested that the folate-modified bexarotene-loaded delivery system, which demonstrated better biocompatibility and potential superiority, could be an appropriate cancer therapy in targeting tumors in the future.

Design and characterization of Amoitone B-loaded nanostructured lipid carriers for controlled drug release.

Amoitone B, a novel compound chemically synthesized as the analogue of cytosporone B, has been proved to own superior affinity with Nur77 than its parent compound and exhibit notable anticancer activity. However, its application is seriously restricted due to the water-insolubility and short biological half-time. The aim of this study was to construct an effective delivery system for Amoitone B to realize sustained release, thus prolong drug circulation time in body and improve the bioavailability. Nanostructured lipid carriers (NLC) act as a new type of colloidal drug delivery system, which offer the advantages of improved drug loading and sustained release. Amoitone B-loaded NLC (AmB-NLC) containing glyceryl monostearate (GMS) and various amounts of medium chain triglycerides (MCT) were successfully prepared by emulsion-evaporation and low temperature-solidification technology with a particle size of about 200 nm and a zeta potential value of about -20 mV. The results of X-ray diffraction and DSC analysis showed amorphous crystalline state of Amoitone B in NLC. Furthermore, the drug entrapment efficacy (EE) was improved compared with solid lipid nanoparticles (SLN). The EE range was from 71.1% to 84.7%, enhanced with the increase of liquid lipid. In vitro drug release studies revealed biphasic drug release patterns with burst release initially and prolonged release afterwards and the release was accelerated with augment of liquid lipid. These results demonstrated that AmB-NLC could be a promising delivery system to control drug release and improve loading capacity, thus prolong drug action time in body and enhance the bioavailability.

Expression of EspA in Lactococcus lactis NZ9000 and the detection of its immune effect in vivo and vitro.

Enterhemorrhagic Escherichia coli (EPEC), an important cause of severe infantile diarrheal disease in many parts of the developing world, produced several recently described virulence determinations. Several of its virulence factors are secreted by type III secretion including EspA, which forms filamentous structures on bacterial surface bridging to the host cell's surface. These structures on bacterial surfaces may deliver other virulence factors directly into the host cell from EHEC. In this study, EspA was expressed in Lactococcus lactis NZ9000 (L. lactis NZ9000). BALB/C mice were immunized by recombinant EspA, and mice sera were assayed for the disruption of E. coli O157:H7 interaction with the host cell. BALB/C mice which were immunized with recombinant EspA produced specific antibody titers, and the difference between the control group and the immune group is marked (P<0.05). The polyclonal mice antisera blocked E. coli O157:H7-induced host cell actin rearrangement and could label E. coli O157:H7 EspA filaments in vitro. Our present findings suggest that L. lactis may be a good candidate to produce oral vaccine, and thus entertains the possibility of developing EspA-oral vaccine in the defense of E. coli O157:H7 infection.