Application progress of radiolabeled drugs in new drug research and development in China / 药学学报

The metabolism study of radiolabeled drugs plays an important role in the development of new drugs. It provides information on drug absorption, metabolism, tissue distribution and excretion, and plays an irreplaceable role in the metabolite safety evaluation and mass balance of new drugs. The new guidance draft on clinical trials of radiolabeled drugs recently released by the US FDA puts forward higher standards and has been widely concerned by the industry. In recent years, in the research and development of new drugs in China, 14C labeled drugs have been used to carry out clinical metabolism studies, which has overcome key technical bottlenecks and accumulated experience. This paper summarizes the above research progress, analyzes the existing problems, and preliminarily looks forward to the future technological development and application.

Research progress of drug toxicity mechanism based on the gut microbiota / 药学学报

The exploration of drug toxicity and mechanisms is a vital component in ensuring the safe use of drugs in clinical practice, as this topic has attracted widespread concern. The intestinal flora holds great significance for drug metabolism, efficacy and mechanism, and is an instrumental metabolic organ that facilitates material information transfer and biotransformation. However, an increasing number of studies have shown that intestinal bacteria are closely related to the toxicity of specific drugs. On the one hand, drugs are transformed into toxic metabolites under the influence of intestinal bacteria, thus inducing direct drug toxicity. On the other hand, the composition and function of the intestinal flora are altered under drug influence, resulting in disruption of endogenous metabolic pathways. Consequently, this disruption compromises the intestinal barrier and affects other organs, leading to indirect drug toxicity. This review meticulously compiles recent examples of drug toxicity attributed to intestinal bacteria, explores in depth the contention that metabolic enzymes of gut microbiota may be of great influence on oral drug toxicity, and outlines prospective avenues for future research on gut microbiota and drug toxicity and mechanisms. This not only provides novel perspectives for the judicious clinical utilization of drugs but also offers insights for the safety assessment of innovative pharmaceuticals.

Advances on toxicity and metabolism of alkaloids from the "toxic" traditional Chinese medicines / 药学学报

The "toxicity" and safety of traditional Chinese medicines have been seriously concerned. Alkaloids are the main pharmacodynamic components of many kinds of traditional Chinese medicines, which show strong biological activity at low concentration. It will also cause toxic side effects but if used improperly. Some alkaloids are both active and toxic, and the safety of related traditional Chinese medicines is particularly noteworthy. The efficacy or toxicity of alkaloids may be the result of the combined action of parent compounds and metabolites, which is not only related to the structural types of compounds, but also has obvious species differences between humans and animals. This review focused on the alkaloids contained in the "toxic" traditional Chinese medicines that are officially recorded in Chinese Pharmacopoeia and the metabolism patterns of alkaloids with different structures as well as the enzymes involved were summarized and discussed by referencing the publications in recent two decades. The present study will be beneficial to the rational use of these traditional Chinese medicines in clinic.

Application of micro-pen electrospray ionization tandem mass spectrometry in rapid detection of metabolic stability of testosterone and dextromethorphan / 药学学报

Probe electrospray ionization (PESI) is one of the typical types of ambient ionization technology, but its application in quantitative analysis is limited due to its poor sampling stability. Previously, we developed a new micro-pen electrospray ionization tandem mass spectrometry (μPen-ESI-MS/MS) method based on PESI. In this study, a μPen-ESI-MS/MS method to measure testosterone and dextromethorphan in liver microsome samples was developed and validated to further applicate in evaluating drug metabolism stability and CYP450 enzyme activity. A μPen-ESI-MS/MS method for detecting the CYP3A4 substrate testosterone and CYP2D6 substrate dextromethorphan in the liver microsome incubation system were developed, and the linearity, precision and accuracy of the method was validated. The validated method was further used to detect the metabolic stability of testosterone in the liver microsome incubation system. The results showed that the μPen-ESI-MS/MS had high efficiency with 0.3 min spraying time of each sample. The standard curve of the testosterone and dextromethorphan has good linearity (R2 > 0.99), the intra- and inter-batch accuracy of testosterone and dextromethorphan was 95.9%-109.3% and 90.5%-107.3%, respectively; the intra- and inter-batch precision was acceptable with RSD values of 2.4%-13.5% and 3.4%-12.1%. The half-lives of testosterone and dextromethorphan in the liver microsome incubation system were 12 min and 14 min, respectively. This study provided a rapid and sensitive μPen-ESI-MS/MS method for the assay of testosterone and dextromethorphan in liver microsome samples, and provided a new strategy for the evaluation of drug metabolism stability and CYP3A4/CYP2D6 activity.

Pharmacological activities of berberine and strategies to improve its oral bioavailability / 药学学报

Berberine is a naturally occurring benzylisoquinoline alkaloid with a wide range of pharmacological activities, such as antibacterial, anticancer, hypolipidemic, antidiabetic and antidiarrheal. Although berberine has a wide range of curative effects, the extremely low bioavailability (< 1%) limits its clinical application. Pure berberine preparations have not yet been approved for any specific disease. The low oral bioavailability of berberine is mainly due to poor solubility caused by self-aggregation under acidic conditions, low permeability, P-glycoprotein (P-gp)-mediated efflux, and liver and intestine metabolism. To improve the oral bioavailability of berberine, researchers have adopted a variety of strategies, including the application of various nano-delivery systems, penetration enhancers and P-gp inhibitors, structural modifications, and development of berberine derivatives. Improving the oral bioavailability of berberine can improve the pharmacological activity of berberine, reduce the dosage, and then reduce the toxic and side effects. This review summarized the various pharmacological activities, metabolism progress and pharmacokinetic characteristics of berberine, the newly discovered berberine target intestinal microbiota and focused on the strategies to improve the oral bioavailability of berberine by improving solubility and permeability, inhibiting P-gp efflux, and structural modification. The research on berberine was prospected, which provided guidance for the in-depth study of berberine.

Metabolism characteristics and pharmacological insights of flavonoids based on the intestinal bacteria / 药学学报

The gut microbiota takes part in many in vivo important physiological activities of host, such as the substance metabolism and energy exchange, etc. The interaction between the host and the intestinal microorganisms has attracted scholars' attention. Flavonoids are a group of polyphenol compounds widely found in natural plants, with the bioactive effect of regulation of glucose and lipid metabolism, anti-inflammation. However, their low bioavailability cause difficulty to clarify the effective substances and the mechanism of flavonoids. Apart from the metabolic effects of liver on flavonoids, recent studies have shown that the gut microbiota can interact with flavonoids. On the one hand, flavonoids can be metabolized by gut microbiota and subsequent metabolites can produce pharmacological activities different from the parent components. On the other hand, flavonoids and their metabolites can in turn regulate the composition and physiological activities of the intestinal flora, which seems to provide a new insight for the research on the effective substances of flavonoids. In this review, we introduced the metabolic characteristics of flavonoids under the actions of intestinal bacteria, and the regulation effects of flavonoids on gut microbiota was also summarized. Meanwhile, the therapeutic effect of flavonoids under the action of intestinal bacteria was discussed.

Construction and application of recombinant human UDP-glucuronosyltransferases expression systems / 药学学报

In the research and development of new drugs, it is very important to investigate the in vitro metabolism of candidate drugs. Traditional models such as liver microsomes have many limitations, while the in vitro model of recombinant human drug metabolizing enzymes is considered as an important and useful approach because of its convenient access, stable activity and low cost. In this study, six major human UDP-glucuronosyltransferases (UGTs) genes (UGT1A1, 1A3, 1A4, 1A6, 1A9 and 2B7) were cloned from human liver cDNA and heterologously expressed in Saccharomyces cerevisiae and baculovirus-infected insect cell. UGT1A1, 1A3, 1A6 and 1A9 were successfully expressed in yeast and showed glucuronidation activity against a variety of different structural types of substrates, but their activities were low. All six UGTs were successfully expressed and exhibited significantly improved glucuronidation activity when Trichopolusia ni cells BTI-TN5B1-4 (High Five) were used as the host. The recombinant human UGTs expressed in insect cells can catalyze the glucuronidation of their specific substrates, and the glucuronidation products were synthesized at milligram-scale with yields of 13%-66% for the first time, of which the structures were identified via MS, 1H NMR, and 13C NMR spectroscopic analysis. Above all, the recombinant human UGTs yeast and insect cell expression systems constructed in this study can be used for in vitro metabolism evaluation in the early stage of new drugs research and development, and also provide a new tool for the synthesis of glucuronide metabolites.

Research progress on the interaction of neuropsychiatric drugs with the gut microbiota / 药学学报

The gut microbiota is an intricate and dynamic community composed of many symbiotic and pathogenic microorganisms, and works closely with the host. In recent years increasing evidence has supported the gut-brain axis theory, lending support for a link between gut microbiota and neuropsychiatric diseases. Since most of the drugs used to treat neuropsychiatric diseases enter the intestinal tract after oral administration, interaction with the gut microbiota is likely. A number of studies have shown that such drugs can change the composition and function of the gut microbiota. At the same time, the gut microbiota also participates in the metabolism of drugs, which in turn have beneficial or harmful effects on brain function. Therefore, the role of gut microbiota in drug metabolism also has attracted attention. This article reviews the research results of the interaction between the two, discusses the influence of neuropsychiatric diseases on the gut microbiota and the effect of the gut microbiota on psychoactive drugs, and provides new ideas for the treatment of various clinical neuropsychiatric diseases.

2018 DMPK research progress in China / 药学学报

This paper summarizes research progresses of Chinese scholars in the field of drug metabolism and pharmacokinetics (DMPK) in 2018. Chinese scholars focused on drug metabolizing enzymes and transporters, and carried out studies on the mechanisms of drug metabolism and transport of active molecules. Topics of research included regulatory mechanisms of drug metabolizing enzymes or transporters, and their implications in drug development and disease etiology or progression. Here, we summarized studies on drug toxicity based on drug metabolism or transport, rational drug use in the clinic, drug metabolism mediated by intestinal flora, metabolism of traditional Chinese medicines, and new technologies or models in DMPK. In recent years, the research focus of drug metabolism in China has transformed from serving for new drug discovery and rational use, to innovation driven and mechanism oriented research. The domestic research topics and technology utilization are gradually aligning with the international conventions.