Latest ArticlesIn current study, adefovir dipivoxil (AD)-acetaminophen (AP) cocrystal (molar ratio, 1:1) was prepared by slow evaporation from acetonitrile, followed by physicochemical characterizations using differential scanning calorimetry, powder X-Ray diffraction and Fourier transform infrared spectroscopy. Molecular modeling showed that the phosphoester group of AD was connected with the amide group of AP through hydrogen bonds. In comparison to crystalline AD, the solubility and dissolution rate of AD from AD-AP cocrystal were significantly enhanced by 1.5-fold and 1.6-fold, respectively. In addition, based on the rat single-pass intestinal perfusion study, the permeabilities of AD in various intestinal sections (i.e., duodenum, jejunum, ileum and colon) were significantly improved (e.g., about 3-fold enhancement in duodenum) after cocrystallization with AP by inhibiting P-glyprotein mediated efflux of AD, which will benefit absorption in vivo and subsequent oral bioavailability of poorly permeable drug AD.
The therapeutic application of artemisinin (ART) is restricted in application due to its poor water solubility and stability. In this study, the long-circulating liposomes (L-Lip) were constructed to improve the solubility and stability of ART. The preparation method, physicochemical properties, serum stability, in vitro release profile and cytotoxicity of the ART loaded long-circulating liposomes were investigated. Using the particle size and entrapment efficiency (EE) as the evaluation index, the preparation procedure was optimized by the Box-Behnken response surface design based on the single factor screening method. The ART loaded long-circulating liposomes were prepared by filming rehydration method, and evaluated with particle size and entrapment efficiency. The optimal formulation was as follows:lipid-cholesterol=5.22:1 (mass ratio), drug-lipid=1:23.15 (mass ratio), lipid concentration=14.35 mg·mL-1, and molar percentage of mPEG=2%. The morphology of L-Lip was uniformly spherical shape according to optimal formulation. The mean size and polydispersity index (PDI) were about (113.3 ±4.7) nm and 0.227 ±0.022 respectively, the zeta potential was (-12.9 ±2.6) mV, and the entrapment efficiency (EE) of ART was (95.88 ±4.8)%. The L-Lip had good stability at 4℃ for 15 days and the particle sizes did not exhibit significant variations in 50% rat plasma over 24 h at 37℃. The in vitro release study of formulation showed a sustained release. Moreover, the cytotoxicity exhibited that blank liposomes were of great safety. Compared with the free ART, the liposome formulation achieved lower cytotoxicity at the high concentration. The L-Lip successfully prepared by a simple filming-rehydration method exhibited ideal physicochemical properties and were enhanced safety, which may sever as a promising nanoplatform for clinical application.
As a common Tibetan herb, Bawo Sebo was mainly used in the treatment of rheumatoid arthritis and urarthritis in Traditional Tibetan medicine. Based on our ethnobotanical survey, the origin of the herb was determined as Swertia verticillifolia T. N. Ho et S. W. Liu (Gentianaceae), endemic to the region of the Qinghai-Tibet Plateau. The diagnostic characters:perennial; stem leaves in whorls; corolla campanulate, yellow-green, 4-lobed; nectary 1 per corolla lobe, naked. Also, its complete chloroplast (cp) genome was sequenced. It is 151 682 bp in length, including a large single copy (LSC) region of 82 623 bp, a small single copy (SSC) region of 18 335 bp and a pair of inverted repeats (IRs) of 25 362 bp. It contains 129 unique genes, including 84 protein-coding genes, 37 tRNAs and 8 rRNAs. This study provides information for understanding the diversity of Swertia cp genomes, and the alpine species identification, conservation and molecular phylogenetic researches of Swertia and Gentianaceae.
Berberine is one of the most studied original natural drugs in China in recent years. It is a new lipid-lowering drug with completely different mechanism from statins, which has been used in the multi-center clinical trials. However, berberine is poorly absorbed in the intestinal tract after oral administration leading a significant pharmacokinetic characteristic of low blood concentration (1%) and bioavailability (< 5%). That is to say, it is difficult to explain the therapeutical effect in vivo by the current pharmacokinetic results. In fact, this phenomenon also exists in a number of clinically effective natural drugs. This review introduces the pharmacokinetic characteristic of berberine by focusing on the gut microbiota to mediate the metabolic process of berberine in vivo. Meanwhile, taking berberine as an example, we emphasized the important role of intestinal bacteria on the pharmacokinetic study on the oral chemical drugs, and put forward a new research mode of drug PK-PD mediated by the gut microbiota.
Hepatic fibrosis is an important pathological process in the development of liver cirrhosis and liver cancer from chronic liver damage. So far there is no effective chemical drug in clinic for treatment of hepatic fibrosis. Therefore, the research in anti-hepatic fibrosis drugs is a hot topic. For drugs currently under research and development, most of the mechanisms of action are related to inhibition of factors that could cause or deteriorate liver fibrosis, including activation and proliferation of hepatic stellate cells, inflammation, oxidative stress and production of extracellular matrix, et al. In this review, we briefly analyze targets and drugs related to the mechanisms mentioned above in order to provide a reference to the future research and development of anti-hepatic fibrosis drugs.
Tumor microenvironment (TME) is the internal environment of tumor. As a functional unit, the microenvironment determines the occurrence and development of tumors. Hypoxia, inflammation and immunosuppression are three major characteristics of TME. Hypoxia signals involve in multiple immunosuppressive pathway. There is communication among the gut microbiota, chronic inflammation and immunity. The three characteristics are associated with each other to form a complex network affecting the metastasis of the tumor. TME also influences the development of immunotherapy and efficacy of drugs in solid tumor. Therefore, it is important to identify the valuable biomarkers to predict disease progression, to elucidate the mechanistic networks in the microenvironment, to develop microenvironment targeting drugs and effective drug combination strategies to improve the drug efficacy. All of these have a profound clinical value.
Neural stem cell is a cell type with the ability of self-renewing and the potential to differentiate into neurons, astrocytes or oligodendrocytes. Neurogenesis is beneficial for the recovery of many neurological diseases, such as stroke, Alzheimer's disease and so on. Neurogenesis capacity can maintain through the whole life, which includes the proliferation, migration and differentiation of neural stem cell, as well as the incorporation into the neuronal network of newborn neurons. The self-renewal and differentiation activities of neural stem cell are regulated by the microenvironment, which is defined as neural stem cell niche. Components of neural stem cell niche include cell-cell interactions, cytokines, extracellular matrix and vascular niche. Illustration of neural stem cell niche impact is far more significant for the treatment of certain nervous system diseases. This review summarizes the current understanding of the relationship between neural stem cell niche and the fate of neural stem cell.
HIV-1 reverse transcriptase (RT) plays an important role in HIV-1 life cycle. At present, the listed NRTIs and NNRTIs targeting the RT showed high efficiency as clinical first-line drugs. However, the rapid emergence of multidrug-resistant viruses and significant cumulative drug toxicities compromises antiretroviral therapy efficacy and limits therapeutic options. Therefore, there is an urgent demand for new types of RT inhibitors with novel mechanism of action to address this challenge. In recent years, additional inhibitors with novel mechanism of action have been reported, including nucleic acid competitive inhibitors, reverse transcriptase-directed mutagenesis inhibitors, primers/templates-competitive reverse transcriptase inhibitors, polymerase-RNase H inhibitors, reverse transcription initiation process inhibitors, peptide inhibitors etc., which have brought new hope to the development of novel anti-HIV drugs. This article focuses on the development of these inhibitors.
Fluorinated compounds, which now make up 20%-25% of all marketed chemical drugs, are playing significant role and showing great potential in medicinal chemistry. Fluorine substitution is always utilized to change the physicochemical properties of the compounds to improve the ADME/T properties. In addition, fluorine substitution leads to improvement of the ligand binding affinity. With respect to molecular level, organofluorine can form various intermolecular interactions with the target proteins, e.g., hydrogen bond, halogen bond, C-F…π interaction, polar interaction and so on. These interactions display unique properties or nature due to the specificity of fluorine atom, which are at the center of attention. This paper reviews the related research background, followed by the research progress of hydrogen bond, halogen bond, C-F…π interaction, polar interaction and some other interactions involved organofluorine.
Primary hepatocellular carcinoma as the main pathological type of liver cancer is one of the common malignant tumors in our country. Liver cancer stem cells (LCSCs) have the characteristics of multidrug resistance, anti-radiotherapy and high tumorigenicity in addition to the characteristics of stem cells, namely, self-renewal, multi-directional differentiation and unlimited proliferation. Based on the above features, relapse and metastasis often occur after the patients being treated with conventional methods, which results in poor prognosis. Effective treatment targeting LCSCs has the potential to cure hepatocellular carcinoma (HCC) completely. This article reviews the common biomarkers used in identification of LCSCs and development of stem cell-targeted therapy for HCC.
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