Follow-on drug approach is to follow-up and make-up of the innovation of pioneering drugs. Since the millennium new molecular entities (NME) have experienced ample optimization, and the patents have claimed in wide ranges, as well as the drug administration requires NME being superior or non-inferior to the existing drugs of the same class. These situations have made the space of follow-on drug innovation narrow and smaller than before. The follow-on drug approach can be concisely differentiated into two aspects:one is to start from the chemistry of small molecules, which are performed with a niche-targeting manipulation to optimize the safety, efficacy and (or) convenience for dose superior to the existing drugs; another proceeds with the macromolecule targets. Based on the knowledge of the mechanism of action or of target mutation, active compounds are constructed through complementary binding or by the reaction mechanism. In this article successful examples are briefly described to illustrate the features of follow-on drug approach.

CRISPR/Cas9 system, consisting of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins, is a prokaryotic immune system that confers resistance to foreign genetic elements such as those present within plasmids and phages. A simple version of the CRISPR/Cas system, type Ⅱ CRISPR, has been modified to edit genomes. By delivering the Cas9 nuclease together with a synthetic guide RNA (sgRNA) into cells, genome can be edited at desired loci site. CRISPR/Cas genome editing techniques have been widely implemented in various species and research areas. In this review, we summarize the several applications of CRISPR/Cas9 in the field of drug discovery and development, which include target gene screening and editing, drug target screening and validation, generation of animal models and treatment of genetic disease, etc. The defects and improvements of CRISPR/Cas9 technology is discussed as well.

Ginsenoside Rg1 is one of the main active components of ginseng with various pharmacological activities including anti-inflammatory, anti-oxidation, anti-aging, anti-tumor and anti-apoptosis. Ginsenoside Rg1 plays a protective role in multiple tissues and organs, which shows the multiple targeting properties of the pharmacological effects. Recently, a number of studies have demonstrated that ginsenoside Rg1 has a protective role in the liver due to its multiple pharmacological effects. In chemical liver injury models, or in other liver injury models, ginsenoside Rg1 can alleviate liver necrosis induced by oxidative stress and inflam-mation. This article provides a review of the recent studies on the efficacy of ginsenoside Rg1 in the treatment of various liver damage and the molecular mechanism.

The New Delhi metallo-β-lactamase-1 (NDM-1) was first reported in 2010, detected in a Klebsiella pneumoniae isolate from a Swedish patient of Indian origin. It has recently attracted extensive attention for its biological activities to catalyze the hydrolysis of almost all of β-lactam antibiotics. The gene for NDM-1 can spread from one strain of bacteria to another by horizontal gene transfer. The most troubling aspect is that there are currently no clinically available inhibitors to block the metallo-β-lactamase action. Therefore, there is urgent need to develop new NDM-1 inhibitors, which can protect β-lactam antibiotics from the hydrolysis effect of NDM-1. In this review, the current research, drug-assistant mechanism and potential NDM-1 inhibitors are summarized.

Compared with the racemate of chiral drugs, enantiopure chiral drugs have been the hot spot of drug research because of their higher selectivity and lower side-effects. Although remarkable progress of asymmetric synthesis has been achieved in the last decades, chiral resolution is regarded as an important approach to obtain chiral drugs. Recent research advancements in the field of chiral resolution of racemic drugs and intermediates are reviewed here. It is clear that combination of chiral separation and racemization to improve the resolution efficiency has become a trend of chiral resolution. In addition, we also introduce some novel resolution methods, such as chiral extraction, membrane resolution, and resolution using nanoparticles.

The key of gene therapy is to deliver the functional gene to the target tissue in the body. The safe and efficient gene carrier is particularly important in the targeted delivery. Multifunctional envelope-type nano device (MEND), based on concept "Programmed packaging", is a new type of gene carrier system, with high encapsulation efficiency, favourable stability, high transfection efficiency, easy preparation, etc. MEND is designed to control intracellular trafficking as well as the tissue distribution of encapsulated compounds such as nucleic acids/proteins/peptides, permitting them to function at the appropriate location. In this paper, research progresses in MEND are reviewed in accordance with three types of payloads:the small interfering RNA (siRNA), DNA and proteins/peptides in recent years.

As a new generation of anti-tumor drugs, taxanes has a good clinical efficacy in the treatment of ovarian cancer, breast cancer, non-small cell lung cancer, head and neck cancer. However, low bioavailability of oral administration from low water solubility and low permeability significantly limited the development of their oral applications. Currently, the marketed preparations were non-oral drug preparations, and the injection contained a large number of surfactants (cremophor EL or Tween 80) and organic solvents (ethanol), which could result in fluid retention, hypersensitivity and other side effects, as well as poor compliance. Oral preparation will be an ideal form for development of taxanes medicines. According to the research by our and other groups in recent years, we investigate the technical strategies enhancing the water solubility and absorptive permeability to improve their oral bioavailability. Among them, we emphasize the application prospects of crystallography technology, and provide a theoretical basis to guide future research in the development of oral preparations for taxanes.

This study was to investigate the effect of RORα activator SR1078 on ovarian cancer cells and its molecular mechanism in vitro. The survival rate of HeyA8 and Hey cells was detected by MTS assay; the apoptosis and cells cycle distribution after SR1078 treatment and the effect of p53 siRNA or PFT-α and PFT-β of p53 inhibitors on SR1078-induced apoptosis of HeyA8 or Hey cells were analyzed by flow cytometry. Western blot was used to detect the effect of SR1078 and p53 siRNA on the expression of p53 protein and the effect of p53 inhibitors alone or in combination with SR1078 on the expression of p53, p-p53 and its downstream pro-apoptotic protein Noxa. The results showed that SR1078 significantly reduced the cell viability and induced apoptosis in HeyA8 and Hey cells. In addition, SR1078 up-regulated the protein expression of p53 and Noxa, and p53 suppression led to significant inhibition of SR1078-induced apoptosis and the expression of Noxa in ovarian cancer cells. In summary, SR1078 induced apoptosis of ovarian cancer cells by activation of p53 signaling pathway.

The study was designed to test the estrogen-like effects about allantoin. The activity of the allantoin was investigated by mouse uterine weight gain test and MCF-7 cell proliferation assay. The levels of E2, FSH and LH were also measured. ICI182, 780, MPP, THC and G15 antagonnist assay and Western blot were adopted to explore the mechanism of allantoin. Allantoin increased the uterus index of premature female mice, the levels of E2 and FSH, and the expression of ERα and GPR30, compared with the control group. Allantoin also promoted the proliferation of MCF-7 cells. Co-incubation of MCF-7 cells with estrogen receptor blockers, ICI182, 780, MPP and G15 abolished the inductive effect of the proliferation. These results suggest that allantoin has estrogenic activities, which are mainly mediated by ERα, GPR30.

Metabolic transformation in vivo is a critical approach in the study of toxicity, but real-time dynamic observation of the transformation is difficult. We proposed that zebrafish toxicity/metabolism synchronization may be used in the analysis of toxicity of Folium Epimedium (Yinyanghuo for Chinese, YYH) and the toxicity may be reduced by Radix Morindae Officinalis (Bajitian for Chinese, BJT). Healthy zebrafish embryos 1 day post fertilization (1 dpf) were exposed to different concentrations of YYH, total flavonoids of YYH (YTF), representative flavonoids (epimedin C and icariin) and their respective in combination with BJT. Death numbers of the embryos or larvals were counted during 1-5 days after dosing (2-6 dpf); embryonic micro-morphology of zebrafish (3 dpf) was observed and pictures were taken. The blank vehicle (0.4% DMSO) was used in the control group, and LC₅₀ value of 2 to 6 dpf was calculated by SPSS16.0. A relative safe concentration was sampled every day to analyze the dynamic metabolites changes of major flavonoids of YYH. The results showed that epimedin A/B/C (EA/EB/EC) and icariin, the major flavonoids of YYH, were dynamically transformed into major metabolites of sagittatoside C (SC) and baohuoside I (BI) by zebrafish. BI was mainly derived from EA, EB and icariin. Neither original form nor their metabolite BI can cause zebrafish poisoning. SC was mainly derived from EC, and its accumulation was closely related to the toxicity of YYH, YTF and EC. After combination with BJT, the metabolism of EC was slowed down and the toxicity was alleviated. Zebrafish toxicity/metabolism synchronization revealed that the toxicity of EC of YYH was increased after metabolism into SC, which maybe the key potential poisonous factor of YYH, and BJT can reduce the toxicity by slowing down the metabolism rate of EC. The data provides new ideas and methods in the study of toxic substances in Chinese medicine and mechanism of detoxicity by combination.

This study was designed to explore the mechanism of Coix seed oil (Coix) impact on the drug resistance, bioluminescence imaging (BLI) and the efflux of D-luciferin potassium salt, the substrate of ABC transporters, in doxorubicin-resistant breast cancer cells. Multidrug resistance (MDR) gene and protein expression were analyzed in the cells by q-PCR and Western blot. First, in order to investigate the effect of the efflux function by ABC protein, a cell line with overexpressed luciferase was established in MCF-7 cell line. BLI was used to monitor the efflux kinetics of D-luciferin potassium salt before and after Coix treament. The results showed that the efflux of D-fluorescein potassium from MCF-7/DOX^Fluc was lessened when pretreated with Coix, which means that Coix may decrease the efflux of other chemotherapies using ABC transporters. Both of the results of q-PCR and Western blot showed that gene and protein expression of ABC transporters such as ABCG2, ABCC1 and ABCB1 were down-regulated by Coix treatment. The efficacy of Coix reversing MDR was verified with the chemotherapy medication doxorubicin (DOX). MTT assay showed that Coix increased the inhibitory effect of DOX on proliferation of MCF-7/DOX, and the optimal combination of ratio was 25 times that of DOX. The results suggest that Coix may reverse MDR of the substrate of ABC transporters from two aspects, one is to cut down the ABC protein efflux function, and the other is to decrease the quantity of ABC gene and protein expression.

This study was carried out to investigate the pharmacokinetics/bioequivalence of levornidazole disodium phosphate by using stable isotope labeled drug, evaluated the pharmacokinetic profile and confirmed the prodrug characteristics of levornidazole disodium phosphate in monkey. Levornidazole (Drug A) and stable isotope ¹⁵N labeled levornidazole disodium phosphate (Drug B) were mixed with equal mole amount (experiment Ⅰ); stable isotope ¹⁵N labeled levornidazole disodium phosphate (Drug B) and levornidazole disodium phosphate (Drug C) were mixed with equal mole amount, respectively. After giving the mixed drugs to the monkey, the concentration of ¹⁵N-levornidazole disodium phosphate, levornidazole disodium phosphate, ¹⁵N-levornidazole and levornidazole in plasma samples of pre-dosing and 24 h after administration were analyzed by a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method. Pharmacokinetic calculations were performed through non-compartmental analysis using WinNonlin software. Two-sided 90% confidence intervals (CI) were used to evaluate the bioequivalence of two drugs. The results showed that levornidazole disodium phosphate was metabolized to levornidazole rapidly after administration, the body exposure were increased with the dosage. The method of bioequivalence used in this study was different from the traditional two periods, crossover design. By using the method of this study, the effects of administration period, intra-individual variability, and sequence of administration on bioequivalence were avoided. The results of this study had successfully supported the pharmacokinetic and bioequivalence study of this drug in human using the same approach.

A new dihydroflavone:mirabiflavone (1), together with two known compounds were isolated from the ethyl acetate extract of the roots of Mirabilis himalaica by using various chromatographic techniques, such as silica gel column, Sephadex LH-20 column, and semi-preparative HPLC. Their structures were elucidated as syringaresinol (2) and lariciresinol (3) by spectroscopic analysis. Compounds 2 and 3 were isolated from this plant for the first time.

Two new diarylheptane derivatives were isolated from Rhizoma Zingiberis by Diaion HP-20, MCI Gel CHP-20, ODS, silica gel column and reverse phase semi-prepared high performance liquid chromatography. Their structures were elucidated by spectrum technology (MS, UV, IR, NMR), which were identified as 3-keto-5R-ethoxy-1-(3-methoxy-4-hydroxyphenyl)-7-(3, 4-dihydroxyphenyl)heptane (1) and 3-keto-5R-ethoxy-1-(3-methoxy-4-hydroxyphenyl)-7-(3-methoxy-4, 5-dihydroxyphenyl)heptane (2). Compounds 1 and 2 are new compounds.

Vancomycin has been widely prescribed as the first-line antibiotic in the treatment of methicillin-resistant Staphylococcus aureus and other serious Gram-positive infections. Due to its large pharmacokinetic (PK) variability and narrow therapeutic range, it requires optimization of dosage to achieve target exposure. In this study, SmartDose, a decision support system for individualization of vancomycin dosage is developed using the maximum a posterior Bayesian estimation (MAPB) by the open-source language R combined with the population PK characteristics of vancomycin in Chinese patients. It provides initial design and adjustment of dose regimens based on the therapeutic drug monitoring (TDM) results, as well as a user-defined module to facilitate optimal vancomycin therapy. SmartDose has a high computational reliability, which is validated by NONMEM, the golden standard PK software. Meanwhile, SmartDose is established as a web-based application and its operational flexibility makes it an efficient tool for vancomycin dose optimization in routine clinical settings.

The Chinese herbal Sophora alopecuroides is widely used to clean intestine and eliminate dampness, and it has good therapeutic effects on treating bacillary dysentery and inflammatory bowel disease, etc. in clinics. However, the mechanism of treatment is not yet well understood. The present study was aimed to explore the mechanism of Sophora alopecuroides treatment of large intestine dampness-heat syndrome (LIDHS). The LIDHS model was performed by the comprehensive factors, including high temperature and humidity environment, high-sugar and high-fat diet, and intraperitoneal injection of Escherichia coli. The blood routine, serum proinflammatory cytokine levels and histopathological changes of intestine were detected and observed. Meanwhile, the serum metabolomic approach was conducted using the method of ultra performance liquid chromatography coupled to quadrupole time-of-flight mass/mass spectrometry (UHPLC-Q/TOF-MS/MS). The results showed that Sophora alopecuroides has good therapeutic effects on the LIDHS rat models. After treatment with Sophora alopecuroides, the abnormality of blood routine indexes as well as proinflammatory cytokines, including IL-1β, IL-2, IL-6 and TNF-α in vivo, tended to be normal, and the histopathological changes of intestine were improved. Through metabolic profiling and protocol analysis, 9 potential metabolic markers may be closely related with the treatment mechanism of Sophora alopecuroides on this disease, including taurine, L-tryptophan, LysoPE, LysoPC, LPA, DG, chenodeoxycholic acid disulfate, traumatic acid and 7-ketodeoxycholic acid, which were involved in taurine and hypotaurine metabolism, glycerophospholipid metabolism, glycerolipid metabolism, tryptophan metabolism and primary bile acid biosynthesis etc. The serum metabolomic approach can be applied to clarify the therapeutic mechanism of Sophora alopecuroides on LIDHS, and provide the theoretical basis for Sophora alopecuroides in clinical practice.

An LC-MS/MS method was developed for the simultaneous determination of fosaprepitant and aprepitant in human plasma, and applied to a pharmacokinetic study of 150 mg fosaprepitant dimeglumine injection to 12 Chinese healthy volunteers. The analytes and internal standards were extracted from plasma by protein precipitation with acetonitrile and separated on a Cortex C18+ (50 mm×2.1 mm, 2.7 μm) column using a gradient elution procedure. Mass spectrometry was performed in negative MRM mode, and parent-to-produce transitions were as follows:m/z 613.1→78.9 for fosaprepitant, m/z 617.0→78.9 for d₄-fosaprepitant, m/z 533.2→275.1 for aprepitant and m/z 537.2→279.1 for d₄-aprepitant. Plasma sample was basified to stabilize fosaprepitant. The standard curves were demonstrated to be liner in the range of 15.0 to 6 000 ng·mL^-1 for fosaprepitant and 10.0 to 4 000 ng·mL^-1 for aprepitant. The intra-day precisions and inter-day precisions and accuracy were within the acceptable limits for all concentrations.

Severe acute pancreatitis (SAP) is characterized by both local and systemic inflammatory responses. This study was designed to develop a site-specific delivery strategy for SAP therapy using celastrol (CLT). First, murine RAW264.7 cells were used as a model of macrophage cell line, cell membranes were obtained by emptying intracellular contents via hypotonic lysing, mechanical membrane disruption, and differential centrifugation. Poly(ethylene glycol) methyl ether-block-poly(lactic-co-glycolic acid) (PEG-PLGA) nanoparticles (NPs) were then prepared by sonication. With the collected membrane materials, macrophage membrane coated PEG-PLGA NPs (RNPs) were then prepared by extrusion through a 400 nm polycarbonate membrane. Biodistribution study in rats with SAP showed RNPs selectively accumulated in the inflamed pancreatic tissues. Compared with CLT loaded NPs, CLT loaded RNPs were proven to effectively attenuate local pancreatic inflammation and systemic inflammation in rats with SAP.

Honokiol (HK) have extensive pharmacological activities, but its poor solubility and instability restricted its clinical application and efficacy exertion. HK nanosuspensions (HK-NSps) were designed in this study in order to solve the problems. HK-NSps were prepared by antisolvent precipitation method, using poly-vinylpyrrolidone (PVP) and bovine serum albumin (BSA) as a combined stabilizer. The particle size was measured using dynamic light scattering method, the morphology was observed by transmission electron microscopy. The size change and drug content of HK-NSps in various physiological media during the storage at ambient temperature was examined to evaluate their storage stability. Dialysis method was used to study their drug release in vitro. MTT assay was used to assess their in vitro cytotoxicity against 4T1 breast cancer cell line. Anti-tumor effect in vivo was also investigated in 4T1 tumor-bearing mice. HK-NSps were prepared with high drug loading content of 48.62%, nearly spherical shape and good storage stability. The average particle size was (83.40 ±1.042) nm, the polydispersity index (PDI) value was 0.223 ±0.011, the zeta potential was (-42.2 ±1.2) mV. HK-NSps showed sustained in vitro drug release and enhanced cytotoxicity in contrast to free HK against 4T1 cells (IC₅₀, 8.36 μg·mL^-1 vs 37.58 μg·mL^-1, P < 0.05). The in vivo study on 4T1 tumor-bearing mice demonstrated that HK-NSps showed good dose-dependent tumor inhibition rate (TIR). In contrast to 4 mg·kg^-1 of PTX injection (TIR, 47.9%), medium and high dose of HK-NSps displayed improved therapeutic efficacy (TIR, 55.67% for 40 mg·kg^-1, 67.28% for 60 mg·kg^-1, P < 0.05). In contrast, the high dose of HK crude drug (60 mg·kg^-1) had TIR of only 54.13% even administrated every day. In conclusion, HK-NSps were prepared with small size, high drug-loading capacity, and good stability. The improved in vitro and in vivo antitumor efficacy demonstrated that HK can be a promising antitumor drug in combination with nanosuspensions technology.

Safflower is a dried flower of the annual herbaceous plant safflower (Carthamus tinctorius L.). As a traditional Chinese medicine, it was widely used in the regulation of blood circulation. Flavonoids are the main active ingredients in safflower. MYB transcription factors are involved in the regulation of flavonoids. The cloning and expression analysis of MYB transcription factor genes in safflower is of great significance, not only for clarifying the regulation mechanism of flavonoids biosynthesis in safflower, but also for the artificial regulation of flavonoid biosynthesis in safflower. Based on the transcriptome data, we used iTAK to annotate the MYB transcription factors in safflower. The MYB transcription factors were cloned and their sequences were analyzed. Besides, their expressions were analyzed by a Real-time PCR. In the experiment, eight long fragment MYB transcription factors were screened and six MYB transcription factors was successfully cloned, named CtMYB-TF1, CtMYB-TF2, CtMYB-TF4, CtMYB-TF5, CtMYB-TF6 and CtMYB-TF7, respectively. The six MYB transcription factors had the core domain of MYB transcription factor family, and evolutionary analysis showed that the CtMYB-TF7 transcription factor was closely related to the factors AtMYBL2 and AtMYB12. Expression analysis showed that the expression of CtMYB-TF5, CtMYB-TF6 and CtMYB-TF7 was low in roots, stems and leaves, and was high in the flower. The results provide a foundation for study of mechanism of molecular regulation of safflower flavonoids.

Currently, the specification grading standard for Astragali Radix can not accurately reflect growth years. The aim of this study is to identify the growth ring number of different parts of 1 to 6 year Hengshan imitative wild culture Astragali Radix, in order to get a different absolute growth years, to classify the accumulation rules of the content of flavonoids and saponins, and to lay the foundation for evaluating quality of Astragali Radix. Observing growth ring numbers of 1-6 years Astragali Radix by means of hand sections and paraffin sections in the study, and analyzing the number of different growth years and different diameter. At the same time, HPLC-UV-ELSD was used to analyze the 12 index components of the samples with absolute growth years of 2 to 6 years. The results indicated that the growth ring number excepting hollow part is consistent with the actual growth period of Astragali Radix and the number of growth rings gradually decreased from the upper to lower. The results of HPLC-UV-ELSD determination showed that the saponins content of 3-year-old Astragali Radix was the highest while the flavonoids content of the 4-year-old reached the maximum. The study provided the basis for foundation of the specification grading standard for Astragali Radix and clinical rational use drug.