Drug discovery calls for faster method development and high-throughput analysis in supporting drug metabolism and pharmacokinetic (PK) studies, whereas the rapid, sensitive, and accurate analysis of biological samples...Drug discovery calls for faster method development and high-throughput analysis in supporting drug metabolism and pharmacokinetic (PK) studies, whereas the rapid, sensitive, and accurate analysis of biological samples remains a significant challenge. For analysis of complex biomatrices (e.g. plasma), liquid chromatography (LC) interfaced to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) has been hampered by adverse matrix effects. For rapid assay development, it would be beneficial to improve the time-consuming method comparison and optimization steps by using generic procedures that work for a variety of compounds. However, injudiciously combining the generic procedures including protein precipitation for sample clean-up and electrospray ionization (ESI) for detection, as well as using conventional short-time isocratic or gradient LC, yield fast assay development, but often at the cost of decreased assay accuracy and increased risk of assay failure. We previously reported that the use of a mobile phase containing an extremely low concentration of ammonium formate (HCOONH4) or formic acid (HCOOH) increased analyte ESI response and controlled against matrix effects. We designated these favorable effects ‘LC-electrolyte effects’. These favorable effects can be achieved in either the positive or the negative ion ESI mode, but not for atmospheric-pressure chemical ionization (APCI). The magnitude of the LC-electrolyte effect on the analyte response depends on both the concentration of the electrolyte modifier added into the mobile phase and its identity, which is also analyte-dependent. In addition, LC is often optimized with more emphasis on improving the analytical sensitivity by concentrating the analyte on the LC column leading to a narrow and symmetric band and achieving sufficient separation between analytes and polar matrix components to avoid adverse ion suppression or enhancement of MS-MS detection. For these reasons, we proposed the so-called ‘pulse gradient system’ for conventional HPLC-based MS-MS analyses of complex biological samples, which is generic and makes method development straightforward. In order to support rapid PK studies for drug discovery, we applied the LC-electrolyte effects and the pulse gradient chromatography to the development of generic procedures that can be used to quickly generate reliable PK data for compound candidates. We herein demonstrate our approach using four model tested compounds (Compd-A,-B,-C, and-D). The analytical methods involve generic protein precipitation for sample clean-up, followed by application of fast LC gradients and the subsequent use of electrospray ionization tandem mass spectrometry (ESI-MS/MS) for individual measurement of the tested compounds in 20 μL plasma samples. Good linearity over the concentration range of 1.6 or 8-25 000 ng/mL (r2>0.99), precision (RSD, 0.45%-13.10%), and accuracy (91%-112%) were achieved through the use of a low dose of formic acid (0.4 mmol/L or 0.015‰) in the methanol/water-based LC mobile phase. The analytical method was quite sensitive, providing a lower limit of quantification of 1.6 pg on-column except for Compd-C (8 pg), and showed negligible ion suppression caused by matrix components. Finally, the assay suitability was demonstrated in simulated discovery PK studies of the tested compounds with i.v./p.o. dosing to rats. This new assay approach has been adopted with good results in our laboratory for many recent discovery PK studies.展开更多
A rapid, sensitive and selective pseudo MRM（p MRM）-based method for the determination of solutol HS15（SHS15） in rat plasma was developed using liquid chromatography/tandem mass spectrometry（LC–MS/MS）. The most ...A rapid, sensitive and selective pseudo MRM（p MRM）-based method for the determination of solutol HS15（SHS15） in rat plasma was developed using liquid chromatography/tandem mass spectrometry（LC–MS/MS）. The most abundant ions corresponding to SHS15 free polyethyleneglycol（PEG）oligomers at m/z 481, 525, 569, 613, 657, 701, 745, 789, 833, 877, 921 and 965 were selected for p MRM in electrospray mode of ionization. Purity of the lipophilic and hydrophilic components of SHS15 was estimated using evaporative light scattering detector（ELSD）. Plasma concentrations of SHS15 were measured after oral administration at 2.50 g/kg dose and intravenous administration at 1.00 g/kg dose in male Sprague Dawley rats. SHS15 has poor oral bioavailability of 13.74% in rats. Differences in pharmacokinetics of oligomers were studied. A novel proposal was conveyed to the scientific community,where formulation excipient could be analyzed as a qualifier in the analysis of new chemical entities（NCEs） to address the spiky plasma concentration profiles.展开更多
Homoisoflavonoids are in the subclass of the larger family of flavonoids having one more alkyl carbon than flavonoids. Among them, 8-C-Methylated homoisoflavones have not been extensively studied for synthesis and bio...Homoisoflavonoids are in the subclass of the larger family of flavonoids having one more alkyl carbon than flavonoids. Among them, 8-C-Methylated homoisoflavones have not been extensively studied for synthesis and biological evaluation. Author’s current objective is to synthesize 8-C-Methylated homoisoflavones by the reaction of 3-C-methylated dihydrochalcones with N,N’-dimethyl (chloromethylene) ammonium chloride generated<em> in situ</em> from DMF and PCl<sub>5</sub> for one carbon extension at about room temperature. The 3-C-methylated dihydrochalcones were synthesized by the reduction of 3-C-methylated chalcones, which were prepared from 3-C-methylated acetophenones and aromatic aldehydes in the presence of base. All the synthesized novel homoisoflavones’s structures were characterized by NMR and Tandem Mass Spectrometry.展开更多
Physiologically based pharmacokinetic(PBPK) modeling and simulation can be used to predict the pharmacokinetic behavior of drugs in humans using preclinical data.It can also explore the effects of various physiologic ...Physiologically based pharmacokinetic(PBPK) modeling and simulation can be used to predict the pharmacokinetic behavior of drugs in humans using preclinical data.It can also explore the effects of various physiologic parameters such as age,ethnicity,or disease status on human pharmacokinetics,as well as guide dose and dose regiment selection and aid drug–drug interaction risk assessment.PBPK modeling has developed rapidly in the last decade within both the field of academia and the pharmaceutical industry,and has become an integral tool in drug discovery and development.In this mini-review,the concept and methodology of PBPK modeling are briefly introduced.Several case studies were discussed on how PBPK modeling and simulation can be utilized through various stages of drug discovery and development.These case studies are from our own work and the literature for better understanding of the absorption,distribution,metabolism and excretion(ADME) of a drug candidate,and the applications to increase efficiency,reduce the need for animal studies,and perhaps to replace clinical trials.The regulatory acceptance and industrial practices around PBPK modeling and simulation is also discussed.展开更多
Rhubarb is a perennial herb belonging to the genus Rheum L. (Polygonaceae). Rhei Radix et Rhizoma (rhubarb roots and rhizomes) is one of the most popular Chinese materia medica and has been widely used for strong laxa...Rhubarb is a perennial herb belonging to the genus Rheum L. (Polygonaceae). Rhei Radix et Rhizoma (rhubarb roots and rhizomes) is one of the most popular Chinese materia medica and has been widely used for strong laxative function. About 200 compounds with six different types of skeletons (anthraquinone, anthrone, stilbene, flavonoids, acylglucoside, and pyrone) have so far been isolated from eighteen species of the genus Rheum L. These constituents showed extensive pharmacological activities including cathartic, diuretic, anticancer, hepatoprotective, anti-inflammatory, and analgesic effects, as well as toxicological effects. Chemical fingerprint, LC-MS, and other analytical techniques have been used for the quality control of rhubarb. This comprehensive review summarizes the researches into the isolation, pharmacological activities, and phytochemical analysis reported since investigations began in the late 1940s. In addition, pharmacokinetic studies and clinical application of rhubarb are also discussed in present paper.展开更多
Managing the dysregulated host response to infection remains a major challenge in sepsis care. Chinese treatment guideline recommends adding Xue Bi Jing, a five-herb medicine, to antibioticbased sepsis care. Although ...Managing the dysregulated host response to infection remains a major challenge in sepsis care. Chinese treatment guideline recommends adding Xue Bi Jing, a five-herb medicine, to antibioticbased sepsis care. Although adding Xue Bi Jing further reduced 28-day mortality via modulating the host response, pharmacokinetic herbedrug interaction is a widely recognized issue that needs to be studied.Building on our earlier systematic chemical and human pharmacokinetic investigations of Xue Bi Jing, we evaluated the degree of pharmacokinetic compatibility for Xue Bi Jing/antibiotic combination based on mechanistic evidence of interaction risk. Considering both Xue Bi Jing-antibiotic and antibiotic-Xue Bi Jing interaction potential, we integrated informatics-based approach with experimental approach and developed a compound pair-based method for data processing. To reflect clinical reality, we selected for study Xue Bi Jing compounds bioavailable for drug interactions and 45 antibiotics commonly used in sepsis care in China. Based on the data of interacting with drug metabolizing enzymes and transporters, no Xue Bi Jing compound could pair, as perpetrator, with the antibiotics. Although some antibiotics could,due to their inhibition of uridine 50-diphosphoglucuronosyltransferase 2 B15, organic anion transporters1/2 and/or organic anion-transporting polypeptide 1 B3, pair with senkyunolide I, tanshinol and salvianolic acid B, the potential interactions(resulting in increased exposure) are likely desirable due to these Xue Bi Jing compounds’ low baseline exposure levels. Inhibition of aldehyde dehydrogenase by 7 antibiotics probably results in undesirable reduction of exposure to protocatechuic acid from Xue Bi Jing.Collectively, Xue Bi Jing/antibiotic combination exhibited a high degree of pharmacokinetic compatibility at clinically relevant doses. The methodology developed can be applied to investigate other drug combinations.展开更多
Ferulic acid(FA) is an active component of herbal medicines. One of the best documented activities of FA is its antioxidant property. Moreover, FA exerts antiallergic, anti-inflammatory, and hepatoprotective effects. ...Ferulic acid(FA) is an active component of herbal medicines. One of the best documented activities of FA is its antioxidant property. Moreover, FA exerts antiallergic, anti-inflammatory, and hepatoprotective effects. However, the metabolic pathways of FA in humans remain unclear. To identify whether human CYP or UGT enzymes are involved in the metabolism of FA, reaction phenotyping of FA was conducted using major CYP-selective chemical inhibitors together with individual CYP and UGT Supersomes. The CYPand/or UGT-mediated metabolism kinetics were examined simultaneously or individually. Relative activity factor and total normalized rate approaches were used to assess the relative contributions of each major human CYPs towards the FA metabolism. Incubations of FA with human liver microsomes(HLM) displayed NADPH-and UDPGA-dependent metabolism with multiple CYP and UGT isoforms involved. CYPs and UGTs contributed equally to the metabolism of FA in HLM. Although CYP1 A2 and CYP3 A4 appeared to be the major contributors in the CYP-mediated clearance, their contributions to the overall clearance are still minor(< 25%). As a constitute of many food and herbs, FA poses low drug-drug interaction risk when co-administrated with other herbs or conventional medicines because multiple phase I and phase II enzymes are involved in its metabolism.展开更多
文摘Drug discovery calls for faster method development and high-throughput analysis in supporting drug metabolism and pharmacokinetic (PK) studies, whereas the rapid, sensitive, and accurate analysis of biological samples remains a significant challenge. For analysis of complex biomatrices (e.g. plasma), liquid chromatography (LC) interfaced to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) has been hampered by adverse matrix effects. For rapid assay development, it would be beneficial to improve the time-consuming method comparison and optimization steps by using generic procedures that work for a variety of compounds. However, injudiciously combining the generic procedures including protein precipitation for sample clean-up and electrospray ionization (ESI) for detection, as well as using conventional short-time isocratic or gradient LC, yield fast assay development, but often at the cost of decreased assay accuracy and increased risk of assay failure. We previously reported that the use of a mobile phase containing an extremely low concentration of ammonium formate (HCOONH4) or formic acid (HCOOH) increased analyte ESI response and controlled against matrix effects. We designated these favorable effects ‘LC-electrolyte effects’. These favorable effects can be achieved in either the positive or the negative ion ESI mode, but not for atmospheric-pressure chemical ionization (APCI). The magnitude of the LC-electrolyte effect on the analyte response depends on both the concentration of the electrolyte modifier added into the mobile phase and its identity, which is also analyte-dependent. In addition, LC is often optimized with more emphasis on improving the analytical sensitivity by concentrating the analyte on the LC column leading to a narrow and symmetric band and achieving sufficient separation between analytes and polar matrix components to avoid adverse ion suppression or enhancement of MS-MS detection. For these reasons, we proposed the so-called ‘pulse gradient system’ for conventional HPLC-based MS-MS analyses of complex biological samples, which is generic and makes method development straightforward. In order to support rapid PK studies for drug discovery, we applied the LC-electrolyte effects and the pulse gradient chromatography to the development of generic procedures that can be used to quickly generate reliable PK data for compound candidates. We herein demonstrate our approach using four model tested compounds (Compd-A,-B,-C, and-D). The analytical methods involve generic protein precipitation for sample clean-up, followed by application of fast LC gradients and the subsequent use of electrospray ionization tandem mass spectrometry (ESI-MS/MS) for individual measurement of the tested compounds in 20 μL plasma samples. Good linearity over the concentration range of 1.6 or 8-25 000 ng/mL (r2>0.99), precision (RSD, 0.45%-13.10%), and accuracy (91%-112%) were achieved through the use of a low dose of formic acid (0.4 mmol/L or 0.015‰) in the methanol/water-based LC mobile phase. The analytical method was quite sensitive, providing a lower limit of quantification of 1.6 pg on-column except for Compd-C (8 pg), and showed negligible ion suppression caused by matrix components. Finally, the assay suitability was demonstrated in simulated discovery PK studies of the tested compounds with i.v./p.o. dosing to rats. This new assay approach has been adopted with good results in our laboratory for many recent discovery PK studies.
文摘A rapid, sensitive and selective pseudo MRM（p MRM）-based method for the determination of solutol HS15（SHS15） in rat plasma was developed using liquid chromatography/tandem mass spectrometry（LC–MS/MS）. The most abundant ions corresponding to SHS15 free polyethyleneglycol（PEG）oligomers at m/z 481, 525, 569, 613, 657, 701, 745, 789, 833, 877, 921 and 965 were selected for p MRM in electrospray mode of ionization. Purity of the lipophilic and hydrophilic components of SHS15 was estimated using evaporative light scattering detector（ELSD）. Plasma concentrations of SHS15 were measured after oral administration at 2.50 g/kg dose and intravenous administration at 1.00 g/kg dose in male Sprague Dawley rats. SHS15 has poor oral bioavailability of 13.74% in rats. Differences in pharmacokinetics of oligomers were studied. A novel proposal was conveyed to the scientific community,where formulation excipient could be analyzed as a qualifier in the analysis of new chemical entities（NCEs） to address the spiky plasma concentration profiles.
文摘Homoisoflavonoids are in the subclass of the larger family of flavonoids having one more alkyl carbon than flavonoids. Among them, 8-C-Methylated homoisoflavones have not been extensively studied for synthesis and biological evaluation. Author’s current objective is to synthesize 8-C-Methylated homoisoflavones by the reaction of 3-C-methylated dihydrochalcones with N,N’-dimethyl (chloromethylene) ammonium chloride generated<em> in situ</em> from DMF and PCl<sub>5</sub> for one carbon extension at about room temperature. The 3-C-methylated dihydrochalcones were synthesized by the reduction of 3-C-methylated chalcones, which were prepared from 3-C-methylated acetophenones and aromatic aldehydes in the presence of base. All the synthesized novel homoisoflavones’s structures were characterized by NMR and Tandem Mass Spectrometry.
文摘Physiologically based pharmacokinetic(PBPK) modeling and simulation can be used to predict the pharmacokinetic behavior of drugs in humans using preclinical data.It can also explore the effects of various physiologic parameters such as age,ethnicity,or disease status on human pharmacokinetics,as well as guide dose and dose regiment selection and aid drug–drug interaction risk assessment.PBPK modeling has developed rapidly in the last decade within both the field of academia and the pharmaceutical industry,and has become an integral tool in drug discovery and development.In this mini-review,the concept and methodology of PBPK modeling are briefly introduced.Several case studies were discussed on how PBPK modeling and simulation can be utilized through various stages of drug discovery and development.These case studies are from our own work and the literature for better understanding of the absorption,distribution,metabolism and excretion(ADME) of a drug candidate,and the applications to increase efficiency,reduce the need for animal studies,and perhaps to replace clinical trials.The regulatory acceptance and industrial practices around PBPK modeling and simulation is also discussed.
基金National Natural Science Foundation of China (81102770)Chinese Traditional Medicine Researches of Special Projects (200707007)+1 种基金the Technological Large Platform for Comprehensive Research and Development of New Drugs in the Twelfth Five-Year "Significant New Drugs Created" Science and Technology Major Projects (2012ZX09301-002-001-026)the Chemical Composition of the Digital Library of TraditionalChinese Medicine for Drug Discovery in the Twelfth Five-Year "Significant New Drugs Created" (2011ZX09307-002-01)
文摘Rhubarb is a perennial herb belonging to the genus Rheum L. (Polygonaceae). Rhei Radix et Rhizoma (rhubarb roots and rhizomes) is one of the most popular Chinese materia medica and has been widely used for strong laxative function. About 200 compounds with six different types of skeletons (anthraquinone, anthrone, stilbene, flavonoids, acylglucoside, and pyrone) have so far been isolated from eighteen species of the genus Rheum L. These constituents showed extensive pharmacological activities including cathartic, diuretic, anticancer, hepatoprotective, anti-inflammatory, and analgesic effects, as well as toxicological effects. Chemical fingerprint, LC-MS, and other analytical techniques have been used for the quality control of rhubarb. This comprehensive review summarizes the researches into the isolation, pharmacological activities, and phytochemical analysis reported since investigations began in the late 1940s. In addition, pharmacokinetic studies and clinical application of rhubarb are also discussed in present paper.
基金funded by grants from the National Science&Technology Major Project of China “Key New Drug Creation and Manufacturing Program”(2017ZX09301012006)the National Basic Research Program of China(2012CB518403)+1 种基金the National Natural Science Foundation of China(81503345)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA12050306)
文摘Managing the dysregulated host response to infection remains a major challenge in sepsis care. Chinese treatment guideline recommends adding Xue Bi Jing, a five-herb medicine, to antibioticbased sepsis care. Although adding Xue Bi Jing further reduced 28-day mortality via modulating the host response, pharmacokinetic herbedrug interaction is a widely recognized issue that needs to be studied.Building on our earlier systematic chemical and human pharmacokinetic investigations of Xue Bi Jing, we evaluated the degree of pharmacokinetic compatibility for Xue Bi Jing/antibiotic combination based on mechanistic evidence of interaction risk. Considering both Xue Bi Jing-antibiotic and antibiotic-Xue Bi Jing interaction potential, we integrated informatics-based approach with experimental approach and developed a compound pair-based method for data processing. To reflect clinical reality, we selected for study Xue Bi Jing compounds bioavailable for drug interactions and 45 antibiotics commonly used in sepsis care in China. Based on the data of interacting with drug metabolizing enzymes and transporters, no Xue Bi Jing compound could pair, as perpetrator, with the antibiotics. Although some antibiotics could,due to their inhibition of uridine 50-diphosphoglucuronosyltransferase 2 B15, organic anion transporters1/2 and/or organic anion-transporting polypeptide 1 B3, pair with senkyunolide I, tanshinol and salvianolic acid B, the potential interactions(resulting in increased exposure) are likely desirable due to these Xue Bi Jing compounds’ low baseline exposure levels. Inhibition of aldehyde dehydrogenase by 7 antibiotics probably results in undesirable reduction of exposure to protocatechuic acid from Xue Bi Jing.Collectively, Xue Bi Jing/antibiotic combination exhibited a high degree of pharmacokinetic compatibility at clinically relevant doses. The methodology developed can be applied to investigate other drug combinations.
基金supported by Chinese National Science & Technology Major Special Project on Major New Drug Innovation(Nos.2008ZXJ09006001 and 2015ZX09J15104)National Natural Science Foundation of China(No.81130067)
文摘Ferulic acid(FA) is an active component of herbal medicines. One of the best documented activities of FA is its antioxidant property. Moreover, FA exerts antiallergic, anti-inflammatory, and hepatoprotective effects. However, the metabolic pathways of FA in humans remain unclear. To identify whether human CYP or UGT enzymes are involved in the metabolism of FA, reaction phenotyping of FA was conducted using major CYP-selective chemical inhibitors together with individual CYP and UGT Supersomes. The CYPand/or UGT-mediated metabolism kinetics were examined simultaneously or individually. Relative activity factor and total normalized rate approaches were used to assess the relative contributions of each major human CYPs towards the FA metabolism. Incubations of FA with human liver microsomes(HLM) displayed NADPH-and UDPGA-dependent metabolism with multiple CYP and UGT isoforms involved. CYPs and UGTs contributed equally to the metabolism of FA in HLM. Although CYP1 A2 and CYP3 A4 appeared to be the major contributors in the CYP-mediated clearance, their contributions to the overall clearance are still minor(< 25%). As a constitute of many food and herbs, FA poses low drug-drug interaction risk when co-administrated with other herbs or conventional medicines because multiple phase I and phase II enzymes are involved in its metabolism.
