Common Approaches of Cytochrome P450 (CYP) Induction Assays

The induction of enzymes is a defensive mechanism for some xenobiotics, but it may alter the drug's safety and efficacy by altering the activity of metabolic enzymes. One of the major families of enzymes involved in phase I metabolism is Cytochrome P450 (CYP) enzymes which may get induced by certain drugs. Concomitant administration of drugs due to chronic disease or polypharmacy, inducers among them may cause toxicity or reduce the plasma concentration at a sub-therapeutic level. This is one of the dangerous types of drug-drug interactions, but predictable & preventable. The CYPs get induced by three nuclear receptors, including the aryl hydrocarbon receptor (AhR); constitutive androstane receptor (CAR); the pregnane X receptor (PXR). Without identification during drug development, enzyme induction phenomenon of a new drug molecule may get noticed only during pharmacovigilance. Though, this CYP induction may not be a barrier for drug development, it may cause possible DDI and treatment failure. According to FDA guidelines, pharmaceutical industries adopted In-vitro, Ex-vivoand In-vivotechniques based on different developmental stages. The results are also interpreted based on regulatory bodies guidelines. For In-vitroassay best accepted method is using primary hepatocytes either fresh or cryopreserved, for Ex-vivoliver slices of different species and in-vivo, clinical investigations are the extreme option. This paper reviews current industry approaches of CYP induction assays to evaluate potentiality for a new drug molecule as an inducer

A time-motion study on the operating room processes among pregnant COVID-19 patients undergoing cesarean section in a tertiary government hospital

@#Objective. This study aims to determine time and motion in the operating room in emergent, urgent and scheduled cesarean section surgeries among pregnant COVID-19 patients. Methodology. A time and motion performance evaluation study was done by computing the following parameters: pre-induction time, pre-incision time, opening time, closing time, for both decision-to-delivery interval (DDI) and overall operative time. Results. During the study period, emergent DDI average was 2 hours and 38 minutes, emergent overall operative time was 1 hour and 31 minutes, urgent DDI average was 3 hours and 51 minutes, and urgent overall operative time of 1 hour and 57 minutes. However, in both urgent and emergent cases, the recommended DDI of 30 minutes, and the average duration of 44.3 minutes for CS were not feasible. Conclusion. The COVID-19 pandemic has negatively affected the provision of surgical obstetric care and OR utilization. Due to the new safety protocol for healthcare workers and patients, there was a significant delay in DDI and overall operative time. The causes were preparation, anesthesia factors or obstetrician factors. Identifying modifiable obstacles may improve the DDI, overall operative time, and the quality of maternal and child birth care during this pandemic.

Applications of drug interaction study in new drug development and regulartory decision-making / 中国临床药理学与治疗学

Drug-drug interactions (DDI) change dose-response relationships, and may result in low efficacy or high toxicity, which are important considerations especially in medical practice with multiple-drug therapies. Predicting clinically significant drug interactions during new drug development is an important part of benefit and risk assessment in drug development and review. This article summarizes the purpose and significance of drug interactions in new drug development, the main content and precautions of DDI studies in vivo and in vitro. Drug interaction studies on novel drug approvals for 2020 in the National Medical Products Administration (NMPA) and US Food and Drug Administration (USFDA) are examined, respectively. It aims to provide reference for DDI studies and regulatory reviews in new drug development in our country.

Targeting uptake transporters for cancer imaging and treatment

Cancer cells reprogram their gene expression to promote growth, survival, proliferation, and invasiveness. The unique expression of certain uptake transporters in cancers and their innate function to concentrate small molecular substrates in cells make them ideal targets for selective delivering imaging and therapeutic agents into cancer cells. In this review, we focus on several solute carrier (SLC) transporters known to be involved in transporting clinically used radiopharmaceutical agents into cancer cells, including the sodium/iodine symporter (NIS), norepinephrine transporter (NET), glucose transporter 1 (GLUT1), and monocarboxylate transporters (MCTs). The molecular and functional characteristics of these transporters are reviewed with special emphasis on their specific expressions in cancers and interaction with imaging or theranostic agents [., I-123, I-131, I-iobenguane (mIBG), F-fluorodeoxyglucose (F-FDG) and C pyruvate]. Current clinical applications and research areas of these transporters in cancer diagnosis and treatment are discussed. Finally, we offer our views on emerging opportunities and challenges in targeting transporters for cancer imaging and treatment. By analyzing the few clinically successful examples, we hope much interest can be garnered in cancer research towards uptake transporters and their potential applications in cancer diagnosis and treatment.

Discovery of cytochrome P450 enzymes-inhibiting components in traditional Chinese medicine / 中国中药杂志

With the widespread use of traditional Chinese medicine(TCM) and the integration of TCM and western medicine, drug-drug interaction(DDI) is considered as a major cause of therapeutic failures and side effects. Cytochrome P450 enzymes(CYPs) are responsible for large number of drug metabolism. CYP3 A4 and CYP2 D6, two important CYP isoforms, are responsible for about 80% drug metabolism of CYPs super family. The inhibition of CYPs is likely to be the most common factor leading to adverse DDI. Therefore, it is of great significance to predict potential CYP3 A4 and CYP2 D6 inhibitors to prevent the DDI. A fast and low-cost me-thod for calculating and predicting CYP inhibiting components was established in this paper, namely support vector machine(SVM) and molecular docking technology which are used to predict and screen drugs. Firstly, 12 qualitative models of two targets were established by using SVM, and the optimal model was selected to predict the compounds in traditional Chinese medicine database(TCMD). Then, molecular docking technology was used to establish docking model. By analyzing the key amino acids involved in drug-target interactions and combining with SVM model, potential inhibitors of CYP3 A4 and CYP2 D6 were found. From the computational results, astin D and epiberberine exhibited inhibition effect on CYP3 A4 and CYP2 D6, respectively. Astin D was only found in astins family from Aster tataricus, while epiberberine was considered to be the active constituent of Coptidis Rhizoma. Therefore, for the risk of DDI, extra attention should be paid to the source of these potential inhibitors, Asteris Radix et Rhizoma and Coptidis Rhizoma. This computational method provides technical support for discovering potential natural inhibitors of CYPs from Chinese herbs by using SVM and molecular docking model, and it is also helpful to recognize the CYPs-mediated DDI existing in TCM, providing research ideas for further pharmacovigilance of integrated therapy.

Potential Drug-Drug Interactions In Heart Failure Patients

Objective: The aim of the present study was to assess the prevalence, risk rating and the severity of hazardous pDDIs (potential drug-drug interactions) in the prescribed pharmacotherapy in the hospital discharged heart failure (HF) patients, primarily with co-administered drugs with narrow therapeutic index (statins, anticoagulants, antithrombotic drugs). Methods: The prescriptions of chronic heart failure patients for one year (January-December 2014) were analyzed for pDDIs through Lexi-interact® software. DDIs belonging to the categories D (Consider therapy modification) and X (Avoid combination) and/or severity of drug interaction-major, were selected for the study. Results: After reviewing the medical records of 985 patients, 239 patients were selected based on the criteria mentioned above. The average number of prescription drugs at hospital discharge was 7.27 medications (±1.84 SD) per patient. The total number of pDDIs was 1483 or approximately 6.2 (±3.89 SD) pDDIs per patient. With respect to the risk rating, in categories D and X were detected 76 (5.12 %) and 2 (0.13 %) pDDI, respectively. The major pDDIs were 108 (7.28 %). Conclusion: HF patients are at high risk of pDDIs. Screening of prescriptions for pDDIs and monitoring of pharmacotherapy in terms of response and associated adverse drug events will contribute to patient safety.

Prediction of potential drug interactions of apigenin based on molecular docking and in vitro inhibition experiments / 中国中药杂志

The purpose of this study was to investigate the effect of apigenin on UGT1 A1 enzyme activity and to predict the potential drug-drug interaction of apigenin in clinical use. First,on the basis of previous experiments,the binding targets and binding strength of apigenin to UGT1 A1 enzyme were predicted by computer molecular docking method. Then the inhibitory effect of apigenin on UGT1 A1 enzyme was evaluated by in vitro human liver microsomal incubation system. Molecular docking results showed that apigenin was docked into the active region of UGT1 A1 enzyme protein F,consistent with the active region of bilirubin docking,with moderate affinity. Apigenin flavone mother nucleus mainly interacted with amino acid residues ILE343 and VAL345 to form hydrophobic binding Pi-Alkyl. At the same time,the hydroxyl group on the mother nucleus and the amino acid residue LYS346 formed an additional hydrogen bond,which increased the binding of the molecule to the protein. These results suggested that the flavonoid mother nucleus structure had a special structure binding to the enzyme protein UGT1 A1,and the introduction of hydroxyl groups into the mother nucleus can increase the binding ability. In vitro inhibition experiments showed that apigenin had a moderate inhibitory effect on UGT1 A1 enzyme in a way of competitive inhibition,which was consistent with the results of molecular docking. The results of two experiments showed that apigenin was the substrate of UGT1 A1 enzyme,which could inhibit the activity of UGT1 A1 enzyme competitively,and there was a risk of drug interaction between apigenin and UGT1 A1 enzyme substrate in clinical use.

Evaluation of hypoglycemic drug-drug interactions by software / 药学实践杂志

Objective To evaluate and analyze the drug-drug interactions(DDI)of different antidiabetic drugs.Methods DDI database Lexi-InteractionTMwas used to evaluate DDI for 28 commonly used antidiabetic medications(including insulin and 27 non-insulin preparations).Results 882 DDIs were identified for 28 drugs.Category C was the top rated DDI(69.8%). Category C,D,X were accounted for 91.2% of the total DDI.28 medication combinations belonged to category X,which should be avoided to use together.Sulfonylureas had the most DDI,followed by metformin.Alpha-glucosidase inhibitors had least DDI.Conclusion Hypoglycemic drugs with less DDI,such as α-glycosidase inhibitors,glucagon-likepeptide1(GLP-1)an-alogs and sodium-dependent glucose transporters 2 inhibitor(SGLT2i)should be considered with high priority for patients tak-ing multiple antidiabetic medications,elderly patients and patients with liver-kidney dysfunction.

Inhibition of berberine on organ anion transporters and its bidirectional trans-membrane transport / 药物评价研究

Objective To study the inhibition of berberine on organ anion transporters (OATs) and its bidirectional trans-membrane transport.Method The transgene cell lines of the organ anion transporters including OAT1,OAT2,OAT3,OAT4,OAT7,and URAT1 were constructed and selected by animal cell transgenic method mediated by transporter Lipo 3000.Wild type (WT) cells were used as control group,and activity of OATs was verified by adding their radiolabeled substrates and inhibitors.The inhibition of 100 μmol/L berberine on the transporters was investigated in vitro.The IC50 of berberine on URAT1 was also determined.The bidirectional transport of berberine was studied through the Caco-2 model.Result The results showed that 100 μmol/L berberine inhibited the activity of OAT1,OAT2,OAT3,OAT4,OAT7 and URAT1 to (70.48±4.23)％,(69.13±1.28)％,(72.12±3.28)％,(79.77±6.49)％,(69.51 ±5.99)％ and (38.4 ± 2.67)％ respectively,the IC50 of berberine to URAT 1 was 13.19 μmol/L,the Papp (A-B) of 50 μmol/L and 100 μmol/L berberine were separately 0.28 × 10-6 and 0.40 × 10-6 cm/s,and the effiux rates were separately 3.18 and 3.15.Conclusion Berberine shows a stronger inhibition to URAT1 compared to OAT1,OAT2,OAT3,OAT4 and OAT7.Berberine may be the substrate of some effiux transporters.This study provides theoretical basis for explaining the low bioavailability ofberberine and forecasting the possible drug-drug interaction.

An update on the role of intestinal cytochrome P450 enzymes in drug disposition

Oral administration is the most commonly used route for drug treatment. Intestinal cytochrome P450 (CYP)-mediated metabolism can eliminate a large proportion of some orally administered drugs before they reach systemic circulation, while leaving the passage of other drugs unimpeded. A better understanding of the ability of intestinal P450 enzymes to metabolize various clinical drugs in both humans and preclinical animal species, including the identification of the CYP enzymes expressed, their regulation, and the relative importance of intestinal metabolism compared to hepatic metabolism, is important for improving bioavailability of current drugs and new drugs in development. Here, we briefly review the expression of drug-metabolizing P450 enzymes in the small intestine of humans and several preclinical animal species, and provide an update of the various factors or events that regulate intestinal P450 expression, including a cross talk between the liver and the intestine. We further compare various clinical and preclinical approaches for assessing the impact of intestinal drug metabolism on bioavailability, and discuss the utility of the intestinal epithelium-specific NADPH-cytochrome P450 reductase-null (IECN) mouse as a useful model for studyingroles of intestinal P450 in the disposition of orally administered drugs.

Inhibition of CYP3A4 and CYP2C9 by podophyllotoxin: Implication for clinical drug–drug interactions.

Podophyllotoxin (PPT) and its derivatives exert significant anti-cancer activities, and one derivative etoposide is often utilized to treat various cancers in the clinic. The aim of the present study is to investigate the inhibitory effects of PPT on major cytochrome P450 (CYP) isoforms in human livers. Inhibition of CYP3A4, CYP2C9, CYP2C8, CYP2D6, CYP2E1 and CYP2A6 by PPT was investigated in the human liver microsomal system. Time-dependent inhibition of CYP3A4 by PPT was also evaluated. The results showed that PPT strongly exhibited inhibitory effects on CYP3A4 and CYP2C9 in a concentration-dependent manner. Half inhibition concentration (IC50) was 1.1±0.3 and 4.6±0.3 μM for CYP3A4 and CYP2C9, respectively. Inhibition kinetic analysis showed that PPT exhibited competitive inhibition towards CYP3A4 and CYP2C9 with Ki of 1.6 and 2.0 μM, respectively. Additionally, PPT exerted time-dependent inhibition towards CYP3A4 and the kinetic parameters were 4.4±2.1 μM and 0.06±0.01 min–1 for KI and kinact, respectively. Our experimental data indicate that potential drug–drug interaction (DDI) might exist when PPT is co-administered with the substrates which mainly undergo CYP3A4- or CYP2C9-mediated metabolism.

The Birth,Development and Applications of Domain-Domain Interaction Databases / 生物化学与生物物理进展

Domains are evolutionarily conserved sequence units and they are structural and functional building blocks of proteins.Interaction between two proteins typically involves binding between specific domains, and identifying interacting domain pairs is an important step towards thoroughly understanding protein function and evolution, constructing protein-protein interaction(PPI) networks, and analyzing pathway at the domain level.A number of interacting and/or functionally linked domain pairs have been identified and the information was organized and hosted in many domain-domain interactions(DDI) databases with the help of further mining experimental data and computational predictions from various input data.First, the 8 computational predicting methods used to acquire DDI data will be introduced.Then the introduction of DDI public databases, including 3DID, iPfam, InterDom, DIMA and DOMINE will be given.And finally, some examples are described about applications of DDI in computational predicting interacting protein pairs, assessment of the reliability for PPI, protein domain annotation, and in pathway study.

Role of CYP hypotype on the metabolism of 629 in human liver microsomes in vitro / 中国药理学通报

0.05). Conclusions In human liver microsome system in vitro,CYP1A2,2B6 and CYP2A6 contribute to the metabolism of 629.It is very important for bioreduction drugs design and development,and provide the basic experimental and theoretical profiles for extensive application in clinic.