Permeability is a key factor in the bioavailability of oral drugs. Therefore, in the early stage of drug discovery, accurate and efficient evaluation of drug permeability is essential. The parallel artificial membrane permeability assay (PAMPA) with Caco-2 cells model was used by the industry as early evaluation methods. At present, the Ussing chamber rat model is also widely used. This review summarizes the human data for the in vivo single-pass perfusion technique (Loc-I-Gut)-the gold standard, and then focuses on the basic principles, experimental operation, and efficiency of the three in vitro methods, with correlation to the effective permeability coefficient (P_eff) and fractional absorbed (Fa) in man. We provide recommendations for the use of proper permeability methods at different stages in drug discovery and development.

In recent years, the phenomenon of glass transition has been gradually applied to the field of pharmaceutics. And it exhibits important influences on multiple operating units of pharmaceutical preparations, and the properties and storage of pharmaceutical intermediates and products. At present, it has been widely used in the process of preparations such as drying, granulation, coating, tableting, holt-melt extrusion, cryogenic comminution, and so on. Meanwhile, it showed guiding significance for the process of preparation intermediates and their products, such as solid dispersion, microcapsule, liposome, particle, tablet, and other preparation intermediates and their products. Therefore, this article conducts a detailed analysis and systematic summary of the application guidance of the phenomenon of glass transition in the preparation process, and its influence on the preparation intermediates and products, so as to provide theoretical guidance for preparation production and product storage.

An UPLC-MS/MS method was established for the quantification of the genotoxic impurities bis(2-chloroethyl)amine hydrochloride and 1-(3-chloropropyl)-4-(3-chlorophenyl)piperazine hydrochloride in trazodone hydrochloride. The chromatographic separation of the two genotoxic impurities was performed on Waters ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm) at 20℃. A mixture of 5 mmol·L^-1 ammonium hydrogen carbonate aqueous solution and acetonitrile at a flow rate of 0.3 mL·min^-1 in gradient elution mode was employed as mobile phase. The UPLC-MS/MS was equipped with electrospray ionization in positive ionization mode and adopted multiple reaction monitoring mode. We found that the calibration curves of the two genotoxic impurities were linear in the range of 0.1-10 ng·mL^-1. The limit of detection was 0.10 ng·mL^-1 for bis(2-chloroethyl)amine hydrochloride and the average recovery was 101.53% (RSD=4.06%). The limit of detection was 0.01 ng·mL^-1 for 1-(3-chloropropyl)-4-(3-chlorophenyl)piperazine hydrochloride and the average recovery was 97.95% (RSD=1.27%). The sample solution was stable for 24 h. No bis(2-chloroethyl)amine hydrochloride was detected in the samples, and the content of 1-(3-chloropropyl)-4-(3-chlorophenyl)piperazine hydrochloride in the samples was within the limit. This research provides a method to improve the quality control standards of trazadone.

A metabolomics method was used to search for chemical markers in prepared slices of Glycyrrhiza uralensis with different degrees of honey processing. Coupled with these metabolomics analytical methods, ultra-performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF/MS) was used to generate global chemical profiles of the raw material of Glycyrrhiza uralensis and the prepared slices. The samples were collected in Shanxi, Hebei Zhangjiakou and Inner Mongolia. A total of 57 chemical components were identified in Glycyrrhiza uralensis by using the UNIFI theoretical database combined with the library of reference samples. Among them, 37 compounds were identified in positive ion mode and 56 compounds were identified in negative ion mode. Unsupervised principal component analysis (PCA) showed that the chemical ingredients differed considerably depending on the extent of processing. Supervised orthogonal partial least squares discriminant analysis (OPLS-DA) was used to differentiate the moderate processing group and the raw group, and partial least squares discriminant analysis (PLS-DA) was used to differentiate the less, the moderate, and the excessive processing groups. The results showed that the contents of glycyrrhizic acid, licoricesaponin G2, and licoricesaponin E2 varied with the extent of processing. The content of these components increased after processing, and reached the highest level when the extent of processing was moderate (P < 0.05). Glycyrrhizic acid, licoricesaponin G2 and licoricesaponin E2 can be regarded as the chemical markers to differentiate the samples with different degrees of processing. These three compounds can be used to monitor the processing of Glycyrrhiza uralensis.

Two dimeric diterpenoid alkaloids were isolated from the whole plant of Aconitum tanguticum (Maxim.) Stapf and their structures were elucidated by extensive analysis of 1D, 2D-NMR and HR-MS data. One is a new compound and named tanguticurine A (1), and the other is the known compound anthoroidine B (2); both were isolated from this plant for the first time. The antiviral activity of compounds 1 and 2 against HCV and EV71 were also evaluated. It was found that compound 1 had a good inhibitory effect on HCV and EV71 with EC₅₀ values of 15.5 and 9.7 μmol·L^-1, respectively, and showed low cytotoxicity. Therefore, compound 1 is a good antiviral lead compound and deserves further study.

In recent years, targeted therapy has become the standard treatment for advanced non-small cell lung cancer (NSCLC), but this treatment method has very limited effect on patients with epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutation. This insertion mutation is the third most common mutation in EGFR. It shrinks the drug binding pocket and gives tumors inherent resistance to available EGFR tyrosine kinase inhibitors (TKIs), resulting in the limited efficiency of the first and second generation of EGFR tyrosine. So far, no targeted therapy has been approved for NSCLC patients with EGFR exon 20 insertion mutations, and there are still no drugs that have met clinical needs. In this case, new treatment strategies using new EGFR TKIs or bispecific antibodies may establish new treatment standards for these patients in the future. In this review, we will summarize all relevant exon 20 insertions reported so far on the structure of EGFR and its influence on EGFR inhibitor sensitivity, as well as the treatment strategies of exon 20 insertions in NSCLC patients, hoping to be a clinical treatment for reference.

Cyclic peptide drugs have gradually become an emerging research direction due to their some favorable properties such as high-efficiency binding affinity, high selectivity, lower toxicity, and stable metabolism. In recent years, the number of cyclic peptide drugs under clinical research has continued to increase. Unlike the previous cyclic peptide drugs, which were mostly derived from natural products and their derivatives, these cyclic peptide drugs are designed by genetically encoded display technologies which are based on rational design and in vitro evolution (such as BT1718, PTG-300, POL6326, etc). Among them, phage display technology has some advantages such as mature research system, low cost, and simpler operation that make it well recognized and praised by the majority of researchers in this field. Here, we reviewed the recent progress of applying phage display technology to explore diverse cyclic peptide libraries, which, we believe, will contribute more valuable candidate cyclic peptide drugs in clinical research.

Studies have found that metformin is not only the preferred drug for lowering blood sugar, but also shows lipid-lowering and weight-loss effects. The purpose of this study was to use a hyperlipidemia hamster model to investigate the lipid-lowering effect of metformin and its effect on important metabolic pathways in lipid metabolism disorders. Fifty golden hamsters were divided into a control group, a model group, metformin high- and low-dose groups, and a simvastatin group. A high-fat diet was fed for 1 week to create the model, and then drug was administered for 11 weeks with the high-fat diet. Serum was taken for measurement of blood lipid and blood glucose at 2, 6, and 9 weeks after administration, and at weeks 3, 5, and 9 feces and urine were collected for ¹H NMR metabolomics tests. After 11 weeks of intravenous injection of[U-¹³C₆] glucose, serum was collected for a ¹³C NMR metabolic flux test. The results showed that the administration of metformin can significantly reduce blood lipids and glucose levels and can significantly affect metabolic pathways such as sugar metabolism, lipid metabolism, ketone metabolism, amino acid metabolism, and intestinal flora metabolism. The results of the metabolic flux analysis showed that the high-fat diet reduced the metabolism of tricarboxylic acids by 37.48%. After administration of low and high doses of metformin the metabolism of tricarboxylic acid increased by 98.14% and 143.10%, respectively. After administration of simvastatin tricarboxylic acid metabolism increased by 33.18%. The results indicate that metformin has a significant effect on promoting energy metabolism. This study used a combination of metabolomics and metabolic flow to explore the effect of metformin on lipid metabolism disorders and quantifies changes in the key pathway of energy metabolism-the tricarboxylic acid cycle. This study provides useful information for the study of the efficacy and mechanism of metformin, as well as a practical technical method for the screening of lipid-lowering drugs based on a hamster model.

Lefamulin (BC-3781) is a semi-synthetic pleuromutilin antibiotic, approved for the treatment of community-acquired bacterial pneumonia (CABP) by Food and Drug Administration (USA) in August 2019, with the commodity name of Xenleta. It is the first pleuromutilin antibiotics used for systemic treatment of bacterial infections in human. Lefamulin binds to the peptidyl transferase center of the 50S ribosomal subunit to prevent peptide transfer, thus inhibits protein synthesis. Lefamulin displays expanded activity against gram-positive organisms, and also shows high activity against atypical microorganism like Mycoplasma pneumoniae. This review discusses the mechanism, bacterial spectrum of activity, preclinical and clinical data of Lefamulin.

Bioorthogonal fluorogenic probes are becoming an ideal tool for live-cell fluorescence imaging. With the tetrazine bioorthogonal fluorogenic probe that displays fluorescence enhancement, the tetrazine plays the dual-role of a bioorthogonal reaction unit and the fluorescence quenching unit. The "off" and "on" states of the fluorescence probe are mainly controlled through inverse electron demand Diels-Alder (IEDDA) bioorthogonal reaction. We designed a series of turn-on tetrazine fluorescent probes with Donor-π-Acceptor (D-π-A) structure to achieve a high signal-to-noise ratio and specificity of fluorescence imaging. This series of probes reacted with the dienophile bicyclononyne, and then generated pyridazine structure in-situ that acted as an electron acceptor, resulting in a new D-π-A effect of fluorescent dyes, turning on the intramolecular charge transfer (ICT) effect. By adjusting the electron-donating groups and the degree of conjugation, tunable fluorescence spectra between 400-647 nm with fluorescence turn-on enhanced up to 500-fold have been achieved. This research lays the foundation for the further optimization of tetrazine bioorthogonal fluorescent probes and their applications in molecular imaging and biomedical fields.