ABSTRACT
Polymer nanomaterials have been attracted more and more attention because of their advantages such as long circulation, reduced immunogenicity and less side effects, and have become a hot research topic in nanomaterials. However, the number of polymer nanomedicines successfully applied in clinical application is very limited, and the unsatisfactory pharmacokinetic behavior is one of the main reasons for thisresult. After polymer nanoparticles enter the body, they will release free drugs and polymer excipients. Polymer nanoparticles are the loaded drugs and free drugs are the active chemicals for efficacy, while polymer excipients may cause excipient drug interactions. Therefore, the focus of the pharmacokinetics study of polymer nanoparticles should not be only limited to the free drugs themselves, but should also focus on the loaded drugs, free drugs and polymer excipients. The dynamic changes of polymer excipients and their metabolites pose new requirements and challenges for the bioanalysis of polymer nanomedicines. The characteristics and application scope of common analytical methods for detection polymer nanomedicines including chromatographic assay will be discussed in this paper. Moreover, this review will also summarize the absorption, distribution, metabolism and excretion of polymer nanomedicines. We hope this review will provide reference for the pharmacokinetics study, safety and effectiveness evaluation of polymer nanomedicines.
ABSTRACT
[Abstract] Objective To elucidate the important role of Nogo-A in climacteric neurodegeneration such as memory impairment by observing memory function and the expression of Nogo-A in hippocampus and striatum of rats under low estrogen condition. Methods Fouthy-five female SD rats were divided into sham operation group, ovariectomized group and ovariectomized estrogen treatment group with 15 rats in each group. Medication was given 2 weeks after ovariectomized. Estrogen treatment group was subcutaneously injected in groin with estrogen [25 μg/ (kg.d)] dissolved in sterile sesame oil. The sham operation group and the ovariectomized group were given the same amount of aseptic sesame oil. Samples were collected after 6 weeks of drug treatment. The difference of memory function of rats in three groups was observed by conditioned fear training experiment, and the expression of Nogo-A in hippocampus and striatum was observed by immunohistochemistry and Western blotting. Results Compared with the sham and estrogen treatment group, memory function in ovariectomized group decreased significantly and the number of Nogo-A positive neurons in hippocampus and striatum of ovariectomized rats was significantly higher than that of sham operation group (P 0. 05). The result of immunoblotting was consistent with the above-mentioned immunohistochemical result. Conclusion The increased expression of Nogo-A in hippocampus and striatum under low estrogen condition may be one of the key reasons for memory impairment in climacteric women.
ABSTRACT
<p><b>OBJECTIVE</b>To construct angiogenesis-specific RGD10-NGR9 dual-targeting superparamagnetic iron oxide nanoparticles, and to evaluate its magnetic resonamce imaging (MRI) features in nude mice and potential diagnostic value in tumor MRI.</p><p><b>METHODS</b>Dual-targeting peptides RGD10-NGR9 were designed and synthesized. Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles were synthesized by chemical co-precipitation method and the surface was modified to be hydrophilic by coating with dextran. The dual-targeting peptides RGD10-NGR9 were conjugated to USPIO. Cell binding affinity and up-taking ability of the dual-targeting USPIO nanoparticles to integrin ανβ3-APN positive cells were subsequently tested by Prussian blue staining and phenanthroline colorimetry in vitro. The RGD10-NGR9 conjugated with USPIO was injected intravenously into xenograft mice, which were scanned by MRI at predetermined time points. The MRI and contrast-to-noise ratio (CNR) values were calculated to evaluate the ability of dual-targeting USPIO as a potential contrast agent in nude mice.</p><p><b>RESULTS</b>P-CLN-Dextran-USPIO nanoparticles with stable physical properties were successfully constructed. The average diameter of Fe3O4 nanoparticles was 8-10 nm, that of Dextran-USPIO was about 20 nm and P-CLN-Dextran-USPIO had an average diameter about 30 nm. The in vitro studies showed a better specificity of dual-targeting USPIO nanoparticles on proliferating human umbilical vein endothelia cells (HUVEC). In vivo, RGD10-NGR9-USPIO showed a significantly reduced contrast in signal intensity and 2.83-times increased the CNR in the tumor MRI in xenograft mice.</p><p><b>CONCLUSION</b>This novel synthesized RGD10-NGR9 dual-targeting USPIO is with better specific affinity in vitro and in vivo, and might be used as a molecular contrast agent for tumor angiogenesis MRI.</p>