Sirolimus 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 C_max of the sustained-release tablets decreased by 49.47%, the T_max 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.

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.

Pro-inflammatory macrophages play key regulatory role in the occurrence and development of rheumatoid arthritis (RA). In this study, we constructed a celastrol (Cel)-loaded polyamide-amine dendrimer (PAMAM) drug delivery system, which could target folate receptor and mitochondria. It could target inflammatory macrophages and realize chemo-photothermal synergistic therapy. Using PAMAM as the nano-carrier, folate receptor-targeting group folic acid (FA) and mitochondria-targeting group IR808 (also known as the photothermal agent) were conjugated with PAMAM through amide reaction, and then complexed with anti-inflammatory drug Cel to prepare the FA-PAMAM-IR808/Cel nanocomplex. In vitro characterization results showed that the drug loading efficiency of the nanocomplex was 50.90%, particle size was between 130 and 160 nm, average potential was between 1.0 and 3.5 mV, the drug release showed pH sensitivity, temperature reached to 42.5 ℃ after near-infrared (NIR) light irradiation for 10 min. In vitro cellular uptake experiments showed that the nanocomplex had obvious folate receptor-targeting and mitochondria-targeting ability. Following irradiation with NIR light, the cytotoxicity and cellular apoptosis enhanced. The secretion of pro-inflammatory factors tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-6 and nitric oxide (NO) decreased in a concentration-dependent manner. This study provided insights for the development of novel anti-RA nanomedicines.

Fifteen compounds were isolated from the 95% ethanol extract of the whole plant of Elephantopus tomentosus L. by silica gel column chromatography, Sephadex LH-20 column chromatography, MCI column chromatography and semi-preparative HPLC methods. Their structures were identified on the basis of physicochemical properties, and spectral data (UV, IR, NMR, MS and CD) analysis as tomenlephanlide A (1), molephantinin (2), molephantin (3), 8-O-methacryloylelephanpane (4), apigenin (5), tricin (6), 2-phenyl acetamide (7), 3, 4-dihydroxybenzoic acid methyl ester (8), caffeic acid methyl ester (9), caffeic acid ethyl ester (10), (+)-(4S)-(2E)-4-hydroxy-2-nonenoic acid (11), E-4-hydroxyhex-2-enoic acid (12), 1H-indole-3-carboxylic acid (13), 1H-indole-3-carbaldehyde (14) and isohematinic acid (15). Among them, compound 1 is a new germacrene-type sesquiterpenoid, 5-15 were obtained from E. tomentosus L. for the first time. It was the first time the absolute configuration of compound 2 was reported. Compound 1 showed weak cytotoxicity against gastric cancer cells (SGC-7901).

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.

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.

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.

The aim is to study the tissue distribution characteristics of eight effective components in normal rats after oral administration of Ziziphi Spinosae Semen (ZSS) aqueous extract. An ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) analysis method was developed and validated for the determination of four flavonoids and four saponins in rat tissue using puerarin and ginsenoside Re as the internal standard (IS), respectively. Tissue samples including the heart, liver, spleen, lung, kidney, muscle, brain, small intestine, and serum, were collected from each rat at 0.5 h, 1.0 h, and 2.0 h after oral administration of ZSS aqueous extract (15 g·kg^-1). All calibration curves exhibited good linearity (r > 0.994 6) over a wide concentration range for all components. The intra-day and inter-day precisions (RSD) at four different levels were both less than 19.77%, and the accuracies (RE) ranged from -19.68% to 19.46%; The extraction recoveries of the eight components ranged from 86.70% to 114.29%, and the matrix effects were from 82.14% to 114.57%. The validated method was successfully applied to the tissue distribution study of the eight components. The levels of swertisin, spinosin, 6‴-feruloylspinosin, and kaempferol-3-O-rutinoside in the small intestine were highest, then followed by the kidney, heart, and liver. Meanwhile, the levels of jujuboside A (JuA), jujuboside B (JuB), and jujuboside A₁ (JuA₁) in the small intestine were highest, then followed by the lung, spleen, and kidney. The concentrations of betulinic acid in the small intestine were higher than heart, lung, kidney, and liver. The flavonoids and saponins of ZSS with extremely low content could pass through the blood-brain barrier. The research results will provide an experimental basis for explaining the mechanism of nourishing the heart and tranquilizing the mind of ZSS. The animal experimental operations involved in this study followed the regulations of the Animal Ethics Committee of Shanxi University of Chinese Medicine and passed the animal experimental ethical review (No. 2021DW172).

Tumor microenvironment (TME) is composed of endothelial cells, pericytes, immune cells, cancer-associated fibroblasts (CAFs), cancer stem cells (CSCs), extracellular matrix (ECM) and other components of the complex biological environment. TME interacts with the tumor cells through a large amount of signaling pathways, participates in the process of tumor progression, invasion, and metastasis. Hence, TME has become a potential therapeutic target for cancer treatment, exhibiting excellent therapeutic potential and research value in the field of cancer treatment. Currently, the novel nanotechnology has been widely applied in anticancer therapy, and nanotechnology-mediated drug delivery system is being explored to apply in TME modulation to inhibit tumor progression. Nanotechnology-mediated drug delivery has many advantages over traditional therapeutic modalities, including longer circulation times, improved bioavailability, and reduced toxicity. This review summarized the research of targeted nano-drug delivery based on TME regulation, including regulation strategies based on CSCs, CAFs, immune cells, ECM, tumor vascularization, exosomes, and microbiota. In addition, we summarized the advantages, opportunities, and challenges of TME regulation strategy compared with traditional treatment strategy, which provides a reference for the application of nano-drug delivery system based on TME regulation strategy in tumor precision therapy.

Gut microbiota is a complex and dynamic system, and is essential for the health of the body. As the "second genome" of the body, it can establish communication with the important organs by regulating intestinal nerves, gastrointestinal hormones, intestinal barrier, immunity and metabolism, thus affecting host′s physiological functions. Short chain fatty acid (SCFA), known as one important metabolite of intestinal microbiota, is regarded as a significant messenger of the gut-organ communication, due to its extensive regulation in the body′s immunity, metabolism, endocrine and signal transduction. In this review, we summarize the interaction between gut-liver/brain/kidney/lung axis and diseases, and focus on the role and mechanism of SCFA in the gut-organ communication, hoping to provide new ideas for the treatment of the related diseases.