Role of Intestinal Microbiota in Baicalin-Induced Drug Interaction and Its Pharmacokinetics

( Keumhan Noh ),( Youra Kang ),( Mahesh Raj Nepal ),( Ki Sun Jeong ),( Do Gyeong Oh ),( Mi Jeong Kang ),( Sangkyu Lee ),( Wonku Kang ),( Hye Gwang Jeong ),( Tae Cheon Jeong ) 영남대학교 약품개발연구소 2016 영남대학교 약품개발연구소 연구업적집 Vol.26 No.-

Since many glycoside compounds in natural products are hydrolyzed by intestinal microbiota when administered orally, it is of interest to know whether their pharmacological effects are derived from the glycoside itself or from the aglycone form in vivo. An interesting example is baicalin versus baicalein, the aglycone of baicalin, which is contained in some herbs from Labiatae including scutellaria baicalensis Georgi and scutellaria Linne. The herbs have been extensively used for treatment of inflammatory diseases in Asia. Although there have been numerous reports regarding the pharmacological effects of baicalin and baicalein in vivo and in vitro, some reports indicated that the glycoside form would hardly be absorbed in the intestine and that it should be hydrolyzed to baicalei.n in advance for absorption. Therefore, the role of metabolism by intestinal rnicrobiota should also be considered in the metabolism of baicalin. In addition, baicalin contains a glucuronide moiety in its structure, by which baicalin and baicalein show complex pharmacokinetic behaviors, due to the interconversion between them by phase II enzymes in the body. Recently, concerns about drug interaction with baicalin and/ or baicalein have been raised, because of the co-administration of Scutellnria species with certain drugs. Herein, we reviewed the role of intestinal rnicrobiota in pharmacokinetic characteristics of baicalin and baicalein, with regards to their pharmacological and toxicological effects.

Calculation of a First-In-Man Dose of 7-O-Succinyl Macrolactin A Based on Allometric Scaling of Data from Mice, Rats, and Dogs

( Keumhan Noh ),( Wonku Kang ) 한국응용약물학회 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.6

7-O-Succinyl macrolactin A (SMA) exerts several pharmacological effects including anti-bacterial, anti-inflammation, and anti-cancer activities. Recently, SMA has been extensively evaluated as an anti-cancer drug. Thus, the objectives of the present study were to characterise the pharmacokinetics of SMA via both non-compartmental and compartmental analysis in mice, rats, and dogs, and to derive an appropriate first-in-man dose based on allometric scaling of the animal data. The time courses of plasma SMA concentrations after intravenous administration to rats and dogs were analysed retrospectively, as were data collected after intraperitoneal SMA injection in mice. Pharmacokinetic parameters were estimated via both noncompartmental and compartmental analysis, and were correlated with body weight and/or the potential maximum life-span. The clearance and distribution volume of SMA in humans were predicted, and a first-in-man dose proposed. A two-compartment model best described the time courses of SMA plasma concentrations after a saturation elimination process was applied to fit the dataset obtained from rats. Incorporation of the maximum potential life-span during allometric scaling was required to improve the estimation of human clearance. The SMA clearance and the distribution volume in the steady state, in a 70-kg adult male, were estimated to be 30.6 L/h and 19.5 L, respectively. To meet the area under the curve (AUC) required for anti-tumour activity, a dose of 100 mg (~1.5 mg/kg) was finally proposed as the first dose for a 70-kg human. Although toxicological profiles derived from non-clinical studies must be considered before any final decision is made, our work will facilitate clinical studies on SMA.

Calculation of a First-In-Man Dose of 7-O-Succinyl Macrolactin A Based on Allometric Scaling of Data from Mice, Rats, and Dogs

Noh, Keumhan,Kang, Wonku The Korean Society of Applied Pharmacology 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.6

7-O-Succinyl macrolactin A (SMA) exerts several pharmacological effects including anti-bacterial, anti-inflammation, and anti-cancer activities. Recently, SMA has been extensively evaluated as an anti-cancer drug. Thus, the objectives of the present study were to characterise the pharmacokinetics of SMA via both non-compartmental and compartmental analysis in mice, rats, and dogs, and to derive an appropriate first-in-man dose based on allometric scaling of the animal data. The time courses of plasma SMA concentrations after intravenous administration to rats and dogs were analysed retrospectively, as were data collected after intraperitoneal SMA injection in mice. Pharmacokinetic parameters were estimated via both noncompartmental and compartmental analysis, and were correlated with body weight and/or the potential maximum life-span. The clearance and distribution volume of SMA in humans were predicted, and a first-in-man dose proposed. A two-compartment model best described the time courses of SMA plasma concentrations after a saturation elimination process was applied to fit the dataset obtained from rats. Incorporation of the maximum potential life-span during allometric scaling was required to improve the estimation of human clearance. The SMA clearance and the distribution volume in the steady state, in a 70-kg adult male, were estimated to be 30.6 L/h and 19.5 L, respectively. To meet the area under the curve (AUC) required for anti-tumour activity, a dose of 100 mg (~1.5 mg/kg) was finally proposed as the first dose for a 70-kg human. Although toxicological profiles derived from non-clinical studies must be considered before any final decision is made, our work will facilitate clinical studies on SMA.

Pharmacokinetic Interaction of Chrysin with Caffeine in Rats

Noh, Keumhan,Oh, Do Gyeong,Nepal, Mahesh Raj,Jeong, Ki Sun,Choi, Yongjoo,Kang, Mi Jeong,Kang, Wonku,Jeong, Hye Gwang,Jeong, Tae Cheon The Korean Society of Applied Pharmacology 2016 Biomolecules & Therapeutics(구 응용약물학회지) Vol.24 No.4

Pharmacokinetic interaction of chrysin, a flavone present in honey, propolis and herbs, with caffeine was investigated in male Sprague-Dawley rats. Because chrysin inhibited CYP1A-selective ethoxyresorufin O-deethylase and methoxyresorufin O-demethylase activities in enriched rat liver microsomes, the pharmacokinetics of caffeine, a CYP 1A substrate, was studied following an intragastric administration with 100 mg/kg chrysin. In addition to the oral bioavailability of chrysin, its phase 2 metabolites, chrysin sulfate and chrysin glucuronide, were determined in rat plasma. As results, the pharmacokinetic parameters for caffeine and its three metabolites (i.e., paraxanthine, theobromine and theophylline) were not changed following chrysin treatment in vivo, despite of its inhibitory effect on CYP 1A in vitro. The bioavailability of chrysin was found to be almost zero, because chrysin was rapidly metabolized to its sulfate and glucuronide conjugates in rats. Taken together, it was concluded that the little interaction of chrysin with caffeine might be resulted from the rapid metabolism of chrysin to its phase 2 metabolites which would not have inhibitory effects on CYP enzymes responsible for caffeine metabolism.

Pharmacokinetic Interaction of Chrysin with Caffeine in Rats

( Keumhan Noh ),( Do Gyeong Oh ),( Mahesh Raj Nepal ),( Ki Sun Jeong ),( Yongjoo Choi ),( Mi Jeong Kang ),( Wonku Kang ),( Hye Gwang Jeong ),( Tae Cheon Jeong ) 한국응용약물학회 2016 Biomolecules & Therapeutics(구 응용약물학회지) Vol.24 No.4

Pharmacokinetic interaction of chrysin, a flavone present in honey, propolis and herbs, with caffeine was investigated in male Sprague-Dawley rats. Because chrysin inhibited CYP1A-selective ethoxyresorufin O-deethylase and methoxyresorufin O-demethylase activities in enriched rat liver microsomes, the pharmacokinetics of caffeine, a CYP 1A substrate, was studied following an intragastric administration with 100 mg/kg chrysin. In addition to the oral bioavailability of chrysin, its phase 2 metabolites, chrysin sulfate and chrysin glucuronide, were determined in rat plasma. As results, the pharmacokinetic parameters for caffeine and its three metabolites (i.e., paraxanthine, theobromine and theophylline) were not changed following chrysin treatment in vivo, despite of its inhibitory effect on CYP 1A in vitro. The bioavailability of chrysin was found to be almost zero, because chrysin was rapidly metabolized to its sulfate and glucuronide conjugates in rats. Taken together, it was concluded that the little interaction of chrysin with caffeine might be resulted from the rapid metabolism of chrysin to its phase 2 metabolites which would not have inhibitory effects on CYP enzymes responsible for caffeine metabolism.

Effects of Baicalin on Oral Pharmacokinetics of Caffeine in Rats

( Keumhan Noh ),( Mahesh Raj Nepal ),( Ki Sun Jeong ),( Sun A Kim ),( Yeon Ji Um ),( Chae Shin Seo ),( Mi Jeong Kang ),( Pil Hoon Park ),( Wonku Kang ),( Hye Gwang Jeong ),( Tae Cheon Jeong ) 한국응용약물학회 2015 Biomolecules & Therapeutics(구 응용약물학회지) Vol.23 No.2

Scutellaria baicalensis is one of the most widely used herbal medicines in East Asia. Because baicalein and baicalin are major components of this herb, it is important to understand the effects of these compounds on drug metabolizing enzymes, such as cytochrome P450 (CYP), for evaluating herb-drug interaction. The effects of baicalin and baicalein on activities of ethoxyresoru- fin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), benzyloxyresorufin O-debenzylase (BROD), p-nitrophenol hydroxylase and erythromycin N-demethylase were assessed in rat liver microsomes in the present study. In addition, the pharmacokinetics of caffeine and its three metabolites (i.e., paraxanthine, theobromine and theophylline) in baicalin-treated rats were compared with untreated control. As results, EROD, MROD and BROD activities were inhibited by both baicalin and baicalein. However, there were no significant differences in the pharmacokinetic parameters of oral caffeine and its three metabolites between control and baicalin-treated rats. When the plasma concentration of baicalin was determined, the maximum concentration of baicalin was below the estimated IC50 values observed in vitro. In conclusion, baicalin had no effects on the pharmacokinetics of caffeine and its metabolites in vivo, following single oral administration in rats.

HPLC-MS/MS analysis of ilimaquinone and its application in a pharmacokinetic study in rats

Son, Heebin,Noh, Keumhan,Kang, Changhyun,Na, MinKyun,Oh, Sangtaek,Song, Im-Sook,Kang, Wonku Pergamon Press 2019 Journal of Pharmaceutical and Biomedical Analysis Vol.166 No.-

<P><B>Abstract</B></P> <P>Ilimaquinone, a metabolite isolated from the marine sponge <I>Hippiospongia metachromia</I>, has antimicrobial, cytotoxic, anti-HIV, anti-inflammatory, and anti-cancer activities. A new quantitative analytical method for determination of ilimaquinone in rat plasma using HPLC-MS/MS was developed and validated. Ascorbic acid was added to ensure the stability of ilimaquinone in plasma. After protein precipitation using acetonitrile plus diclofenac as an internal standard, the analytes were chromatographed on a biphenyl column with a mobile phase of methanol and water (8:2, v/v, including 0.1% formic acid). This method was successfully applied in a pharmacokinetic study of ilimaquinone after oral administration in rats.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ilimaquinone isolated from <I>Hippiospongia metachromia</I> exerts pharmacological actions. </LI> <LI> A new analytical method for determination of ilimaquinone in rat plasma using HPLC-MS/MS was developed and validated. </LI> <LI> Ascorbic acid was added to ensure the stability of ilimaquinone in plasma. </LI> <LI> This method was successfully applied in a pharmacokinetic study of ilimaquinone after oral administration in rats. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Pharmacometabolomic Approach to Predict QT Prolongation in Guinea Pigs

( Jeonghyeon Park ),( Keumhan Noh ),( Hae Won Lee ),( Mi Sun Lim ),( Sook Jin Seong ),( Jeong Ju Seo ),( Eun Jung Kim ),( Wonku Kang ),( Young Ran Yoon ) 영남대학교 약품개발연구소 2013 영남대학교 약품개발연구소 연구업적집 Vol.23 No.0

Drug-induced torsades de pointes (TdP), a life-threatening arrhythmia associated with prolongation of the QT interval, has been a significant reason for withdrawal of several medicines from the market. Prolongation of the QT interval is considered as the best biomarker for predicting the torsadogenic risk of a new chemical entity. Because of the difficulty assessing the risk for TdP during drug development, we evaluated the metabolic phenotype for predicting QT prolongation induced by sparfloxacin, and elucidated the metabolic pathway related to the QT prolongation. We performed electrocardiography analysis and liquid chromatography-mass spectroscopy-based metabolic profiling of plasma samples obtained from 15 guinea pigs after administration of sparfloxacin at doses of 33.3, 100, and 300 mg/kg. Principal component analysis and partial least squares modelling were conducted to select the metabolites that substantially contributed to the prediction of QT prolongation. QTc increased significantly with increasing dose (r = 0.93). From the PLS analysis, the key metabolites that showed the highest variable importance in the projection values (>1.5) were selected, identified, and used to determine the metabolic network. In particular, cytidine-5`-diphosphate (CDP), deoxycorticosterone, L-aspartic acid and stearic acid were found to be final metabolomic phenotypes for the prediction of QT prolongation. Metabolomic phenotypes for predicting drug-induced QT prolongation of sparfloxacin were developed and can be applied to cardiac toxicity screening of other drugs. In addition, this integrative pharmacometabolomic approach would serve as a good tool for predicting pharmacodynamic or toxicological effects caused by changes in dose.

Short Communication : Quantitative determination of aceclofenac and its three major metabolites in rat plasma by HPLC-MS/MS

( Eunyoung Kim ),( Byoungki Ahn ),( Keumhan Noh ),( Wonku Kang ),( Hye Sun Gwak ) 영남대학교 약품개발연구소 2013 영남대학교 약품개발연구소 연구업적집 Vol.23 No.0

We developed a method for the simultaneous quantification of aceclofenac and its three major metabolites in rat plasma. After protein precipitation with acetonitrile including flufenamic acid as an internal standard (IS), aceclofenac, diclofenac, 4`-hydroxyaceclofenac, 4`-hydroxydiclofenac, and the IS were chromatographed on a reverse-phase C18 analytical column. The isocratic mobile phase of acetonitrile/0.1% formic acid (aq; 9:1 [v/v]) was eluted at 0.3 mL/min. Quantification was performed on a triple-quadrupole mass spectrometer using electrospray ionization, and the ion transitions were monitored in selective reaction-monitoring mode. The coefficient of variation in the assay precision was less than 8%, and the accuracy was 92-103%. This method was successfully used to measure the concentrations of aceclofenac and its three major metabolites in rat plasma following the oral administration of a single 20 mg/kg oral dose of aceclofenac.

Atorvastain과 Telmisartan의 약물상호작용

박진남 ( Jinhyun Park ),노금한 ( Keumhan Noh ),임미선 ( Misun Lim ),강원구 ( Wonku Kang ) 영남대학교 약품개발연구소 2014 영남대학교 약품개발연구소 연구업적집 Vol.24 No.0

Purpose: Atorvastatin, a HMG-CoA reductase inhibitor is widely prescribed in hyperlipidemic patients and telmisartan,an angiotensin receptor blocker is frequently used in the treatment of hypertension. Both drugs are substrates of organicanion transporting polypeptide (OATP) expressed in basolateral membrane in the liver, and undergo high first passmetabolism. Therefore, OATP-mediated hepatic uptake is important for disposition and metabolism of these drugs. Thepresent study was designed to investigate the pharmacokinetic interactions between atorvastatin and telmisartan in rats. Method: Young adult SD rats were divided into three groups (n=6, each) and atorvastatin (10 mg/kg) and telmisartan(4 mg/kg) were orally given alone and together. Heparinized blood was serially taken and plasma concentrations of bothdrugs were measured using HPLC-MS/MS. Pharmacokinetic parameters of two drugs were calculated. Results: No significantpharmacokinetic change was found except a delay of time to peak of telmisartan when administered with atorvastatin. Each drug at the present dosage seemed to be insufficient to alter the pharmacokinetic parameters of itscounterpart drug. Conclusion: Conclusively, co-administration of atorvastatin and telmisartan may lead to negligibleclinical consequences.