Latest ArticlesSirolimus self-microemulsion-mesoporous silicon sustained release tablets were prepared in order to improve the dissolution of the insoluble drug sirolimus and reduce its side effects. Firstly, sirolimus self-microemulsion was prepared and cured with mesoporous silicon. Secondly, the suitable excipients were selected according to the appearance, hardness and in vitro release rate. The sustained-release tablets with hydroxypropyl methylcellulose (HPMC) as skeleton material were prepared by powder direct pressing method, and the formulation was optimized by central composite design-response surface method to investigate the drug release in vitro. Finally, the pharmacokinetics was carried out in beagle dogs using the commercial sirolimus tablets as references. The final formulation of sustained-release tablets is as follows: 162 mg of sirolimus self-microemulsion-mesoporous silica (1∶1, w/w), 80 mg of HPMC K4M and 80 mg of carboxymethyl starch sodium, the microcrystalline cellulose is 168 mg. The results of in vitro release test showed that the self-made sustained-release tablets released slowly within 12 h, which conformed to the Ritger-Peppas model. The in vivo test results showed that compared with the commercial sirolimus tablets, the Cmax of the sustained-release tablets decreased by 49.47%, the Tmax of the sustained-release tablets was prolonged by 5.1 times, and the relative bioavailability was 105.81%. Sirolimus self-microemulsion-mesoporous silicon sustained-release tablets have good sustained-release effects in vitro and in vivo, which provides a reference for the solubilization of other insoluble drugs and the research and development of sustained-release preparations. Animal experiments and welfare processes were reviewed and approved by the Animal Ethics Committee of the 900TH Hospital of the Joint Logistics support Force.
1-Deoxy-D-xylulose-5-phosphate synthase (DXS), the first key enzyme in 2-methyl-D-erythritol-4-phosphate (MEP) pathway, catalyzes the condensation of glyceraldehyde-3-phosphate with pyruvate to 1-deoxy-xylose-5-phosphate (DXP). In this study, PgDXS1, PgDXS2, and PgDXS3 genes were cloned from the root of Platycodon grandiflorum (P. grandiflorum). The open reading frame (ORF) of PgDXS1, PgDXS2, and PgDXS3 were 2 160, 2 208, and 2 151 bp in full length, encoding 719, 735, and 716 amino acids, respectively. Homologous alignment results showed a high identity of PgDXSs with DXS in Hevea brasiliensis, Datura stramonium and Stevia rebaudiana. The recombinant expression plasmids of pET-28a-PgDXSs were constructed and transformed into Escherichia coli (E. coli) BL21 (DE3) cells, and the induced proteins were successfully expressed. Subcellular localization results showed that PgDXS1 and PgDXS2 were mainly located in chloroplasts, and PgDXS3 was located in chloroplasts, nucleus and cytoplasm. The expression of three DXS genes in different tissues of two producing areas of P. grandiflorum were assayed via real-time fluorescence quantitative PCR, and the results showed that all of them were highly expressed in leaves of P. grandiflorum from Taihe. Under methyl jasmonate (MeJA) treatment, the expression levels of three PgDXS genes showed a trend of first decreasing and then increasing at different time points (3 - 48 h), and the activity of DXS showed a trend of first increasing and then decreasing in three tissues of P. grandiflorum. This study provides a reference for further elucidating the biological function of PgDXS in terpenoid synthesis pathway in P. grandiflorum.
Artemisia argyi (A. argyi) is a Chinese herbal medicine in China. The main active components are volatile oils, flavonoids, and other compounds, which have various pharmacological activities. Methoxylated flavonoids are the main active ingredients in A. argyi. Flavonoid O-methyltransferase (FOMT) is a key enzyme in the O-methylation of flavonoids. In order to further understand the function and characteristics of FOMT proteins, this paper carried out the whole genome mining and identification of FOMT genes in A. argyi and performed phylogenetic, chromosomal localization, gene sequence characterization, subcellular localization prediction, protein structure, gene structure analysis, and expression pattern analysis. The results showed that a total of 83 FOMT genes were identified in the genome of A. argyi. The phylogenetic tree shows that FOMT genes are divided into two subgroups, CCoAOMT (caffeoyl CoA O-methyltransferase) subfamily (32 genes) and COMT (caffeic acid O-methyltransferase) subfamily (51 genes). Gene sequence analysis showed that the number of amino acids encoded by FOMT was 70-734 aa, the molecular weight was 25 296.55-34 241.3 Da, and the isoelectric point was 4.51-9.99. Compared with 32 members of the CCoAOMT subfamily, nearly 1/3 of the 51 members of the COMT subfamily were hydrophobic proteins and 2/3 were hydrophilic proteins. Subcellular localization prediction showed that more than 80% of CCoAOMT subfamily members were located in the cytoplasm, and 96% of COMT subfamily members were located in the chloroplast. COMT subfamily members have more motifs than CCoAOMT subfamily members. The N-terminal motifs of COMT subfamily proteins are relatively variable, while the C-terminal motifs are relatively conserved. Expression pattern analysis showed that CCoAOMT subfamily members were mainly expressed in roots, while COMT members were mainly expressed in leaves. Some FOMTs showed the tissue expression specificity by real-time quantitative PCR analysis, especially in leaves. In this study, we identified and analyzed the FOMT gene family in A. argyi, and provided a theoretical basis for further research on the function of FOMTs and the biosynthesis of methylated flavonoids in A. argyi.
Dihydroflavonol 4-reductase (DFR) plays an essential role in the biosynthesis of anthocyanin and regulation of plant flower color. Based on the transcriptome data of Cistanche tubulosa (Schenk) Wight, a full-length cDNA sequence of CtDFR gene was cloned by reverse transcription-polymerase chain reaction (RT-PCR). CtDFR contains an open reading frame (ORF) of 1 263 bp which encodes 420 amino acids with a predicted molecular weight of 47.5 kDa. The sequence analysis showed that CtDFR contains a nicotinamide adenine dinucleotide phosphate (NADPH) binding domain and a specific substrate binding domain. The expression analysis indicated that CtDFR was highly expressed in red and purple flowers, and the relative expression levels were 4.04 and 19.37 times higher than those of white flowers, respectively. The recombinant CtDFR protein was expressed in E.coli BL21 (DE3) using vector pET-28a-CtDFR and was purified. In vitro enzyme activity analysis, CtDFR could reduce three types of dihydroflavonols including dihydrokaempferol, dihydroquercetin, and dihydromyricetin to leucopelargonidin, leucocyanidin and leucodelphinidin. Subcellular localization analysis showed that CtDFR was mainly localized in the cytoplasm. These results demonstrate that CtDFR plays an important role in regulation of flower color in C. tubulosa and make a valuable contribution for the further investigation on the regulation mechanism of C. tubulosa (Schenk) Wight flower color.
Ribonucleic acid (RNA) medicines have strong therapeutic potential for numerous rare genetic illnesses and malignancies because of its exact programmability based on Watson-Crick base pairing principle and unique ability to regulate gene expression. However, RNA medicines still have limitations in many areas, including stability, half-life time, immunogenicity, organ selectivity, cellular uptake and endosomal escape efficiency despite their great therapeutic potentials. This review briefly introduced numerous RNA medications [mostly messenger RNA (mRNA), small interfering RNA (siRNA), microRNA (miRNA) and antisense oligonucleotide (ASO)] that have intrigued of researchers in recent years, as well as their action mechanism in vivo. A number of delivery techniques, such as chemical modification, ligands coupling and nanocarriers have been proposed. The manufacture and applications of lipid nanoparticle, polymer nanoparticle and exosomes were discussed in depth. The goal of this work is to give a theoretical foundation and design concepts for the development of effective and safe RNA delivery technology, as well as to facilitate RNA therapeutic clinical translation.
In the research on cancer theranostics, most environment-sensitive drug delivery systems can only achieve unidirectional and irreversible responsive changes under pathological conditions, thereby improving the targeting effect and drug release performance of the delivery system. However, such irreversible changes pose potential safety hazards when the dynamically distributed delivery system returns to the blood circulation or transports to the normal physiological environment. Intelligent reversible drug delivery systems can respond to normal physiological and pathological microenvironments to achieve bidirectional and reversible structural changes. This feature will help to precisely control the drug release of the delivery system, prolong the blood circulation time, improve the targeting efficiency, and avoid the potential safety hazards of the irreversible drug delivery system. In this review, we describe the research progress of intelligent reversible drug delivery system from two main aspects: controlled drug release and prolonged blood circulation time/enhanced cellular internalization of drug.
Malignant tumors are major diseases that endanger human health. Due to their complex and variable microenvironment, most anti-tumor drugs cannot precisely reach the focal tissue and be released in a controlled manner. Intelligent responsive nano carriers have become a hot spot in the field of anti-tumor drug delivery systems. As an excellent nano material, mesoporous silica has the advantages of non-toxic, stable, adjustable pore volume and pore diameter, and easy functional modification on the surface. By virtue of its perceptive response to the tumor microenvironment or physiological changes, it can achieve the targeted drug release or controlled drug release of the drug delivery system in the tissue, making it an ideal carrier for intelligent response drug delivery system. In this paper, we review the design strategies and current research status of smart responsive anti-tumor drug delivery systems based on mesoporous silica, in order to provide a reference for the development of anti-tumor drug nanoformulations.
Exosome is a self-secreted phospholipid bilayer nanovesicles, and has shown great potential in drug delivery field due to the important advantages of low immunogenicity and homologous targeting. Phototherapy, mainly includes photodynamic therapy (PDT) and photothermal therapy (PTT), utilize light to activate photoactive drug for tumor cell killing. The advanced therapeutic strategy shows low toxic side-effect and non-invasion precise advantages, and thus has made great progress in tumor treatment over the past few years. Therefore, using exosomes as a drug delivery system to deliver phototherapeutic agents can improve therapeutic performances with a reduced side-effect, and further enhance their application potential for clinical tumor therapy. This review focus on the rising cross-subjects field involving exosomes and phototherapy, and mainly introduce the research progress and relative case of exosomes-based delivery system for cancer phototherapy. Additionally, the advantages and challenges of exosome-based phototherapy are also discussed and proposed.
Since the application of biomedical nanotechnology in the field of drug delivery breathes new life into the research and development of high-end innovative agents, a substantial number of novel nano-drug delivery systems (nano-DDSs) have been successively developed and applied in the clinical practice. Among them, small molecule pure drug and prodrug-based nanoassemblies have grasped great attention, owing to the facile fabrication, ultrahigh drug loading and feasible industrial production. Herein, we provide an overview on the latest updates of small-molecule nanoassemblies. Firstly, the self-assembled prodrug-based nano-DDSs are introduced, including nanoassemblies formed by amphiphilic monomeric prodrugs, hydrophobic monomeric prodrugs and dimer monomeric prodrugs. Then, the recent advances on nanoassemblies of small molecule pure chemical drugs and biological drugs are presented. Furthermore, carrier-free small-molecule hybrid nanoassemblies of pure drugs and/or prodrugs are summarized and analyzed. Finally, the rational design, application prospects and clinical challenges of small-molecule self-assembled nano-DDSs are discussed and highlighted. This review aims to provide scientific reference for constructing the next generation of nanomedicines.
Local anesthetic drugs are commonly used to block the conduction function of patient's nerves temporarily for anesthesia during surgery or to provide targeted analgesia after trauma. Compared with general anesthetics, local anesthetics makes less impact on the physiological status and alleviates pain complications in the presence of clear consciousness. However, its clinical application is still limited by its systemic toxicity, as well as toxicity to nerves and muscles, duration of action and lack of penetration. Nanotechnology can help it penetrate the physiological barrier, prolong the time of nerve block, and reduce toxic side effects. In addition, by building a light-responsive release system, local anesthetics can be released on demand, enhancing drug effectiveness and safety. However, in addition to the problems of poor consistency and high production costs, the system of light response release is still limited in application due to the limitation of the depth of penetration of the tissue. According to the current research progress, this paper briefly introduces and analyzes the main dosage forms, hoping to provide new ideas for the responsive release of local anesthetic drugs.
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