Avaliação da interação farmacológica de antifúngicos e quimioterápicos: uma revisão sistemática / Evaluation of pharmacological interaction of antifungals and chemotherapy: a systematic review

Objetivo: avaliar, por meio da literatura existente, a interação farmacológica de antifúngicos e quimioterápicos. Métodos: foi realizado um estudo de revisão sistemática de acordo com o diagrama de fluxo do processo de pesquisa PRISMA. Os descritores escolhidos foram: drug interactions, CYP inhibitors, antifungal e antineoplastic, mediante análise realizada no MESH. As bases de dados escolhidas foram: Pubmed, Lilacs e Scielo. O período considerado para busca de artigos publicados foi de 2015 a 2020. Resultados: no banco de dados PubMed, foram encontrados 54 artigos, enquanto, nas bases Lilacs e Scielo, não foram encontrados artigos de acordo com os critérios estabelecidos. Dos 54 artigos, 7 foram selecionados para esta revisão. O intervalo com maior número de publicações foi de 2015-2016. Os antifúngicos mais citados nos resultados foram os inibidores fortes da CYP (Cetoconazol, Itraconazol e Voriconazol). Conclusão: a revisão sistemática da literatura mostrou que não existe uma correlação exata entre a interação farmacológica dos antifúngicos com os antineoplásicos, quando administrados de forma simultânea. São necessários mais estudos atuais que possam monitorar e estabelecer, de forma precisa, a relação dessas interações.

Objective: to evaluate, through the existing literature, the pharmacological interaction of antifungals and chemotherapeutics. Methods: a systematic review study was conducted according to the PRISMA research process flow diagram. The descriptors were chosen by analysis performed in MESH. The descriptors chosen were: drug interactions, CYP inhibitors, antifungal and antineoplastic. The databases chosen were: Pubmed, Lilacs, and Scielo. The period considered for the search of published articles was from 2015 to 2020. Results: in the PubMed database, 54 articles were found, while in the Lilacs and Scielo databases, no articles were found according to the established criteria. Of the 54 articles, 8 were selected for this review. The interval that had the highest number of publications was 2015-2016. The most cited antifungal drugs in the results were the strong CYP inhibitors. Conclusion: the systematic review of the literature showed that there is no exact correlation between the pharmacological interaction of antifungals with antineoplastic drugs when administered simultaneously. More current studies are needed that can accurately monitor and establish the relationship between these interactions.

Efectos adversos de lopinavir/ritonavir en enfermedad grave por coronavirus (COVID-19) / Adverse effects of lopinavir/ritonavir in critically ill patients with COVID-19

Resumen Durante el transcurso de la pandemia causada por el virus SARS-CoV-2 se han utilizado diferentes fármacos como potenciales tratamientos específicos con el objetivo de lograr mejoría clínica y/o disminuir la mortalidad de los afectados, pero al tratarse de una enfermedad hasta ahora desconocida, la evidencia acerca de su seguridad y eficacia se va construyendo a medida que se los prescribe. La farmacovigilancia intensiva en este contexto permite detectar eventos adversos y mediante su reporte y análisis inferir el perfil de seguridad en cada indicación. Se realizó un estudio observacional, retrospectivo, en un único centro, en el cual se relevaron los eventos adversos en 23 pacientes adultos en estado crítico, de los cuales 18 recibieron lopinavir/ ritonavir como tratamiento empírico, entre el 15 de marzo y el 15 de junio de 2020, durante su internación en una Unidad de Cuidados Intensivos. Se describe el tipo de eventos adversos, su gravedad y si fueron motivo de suspensión del tratamiento. Los resultados del presente análisis muestran una alta tasa de eventos adversos (10/23, 43%) entre los que recibieron lopinavir/ritonavir, llevando en la mayoría de los casos a la decisión de suspender el mismo antes de completar el tratamiento. Aun con las limitaciones propias del reducido número de casos, la divulgación de dichos resultados aporta evidencia para definir el perfil de seguridad de la combinación lopinavir / ritonavir usado en enfermedad grave por SARS-CoV-2.

Abstract During the SARS-CoV-2 pandemic many drugs have been used as potential treatments in order to improve the clinical outcome and reduce the mortality. But since it is a currently unknown disease, the evidence about efficacy and safety is built as the drugs are prescribed. In this context, intensive pharmacovigilance allows early detection of adverse events, and thereby infer the safety profile of the indication. We conducted an observational, retrospective, single-center study involving adult patients with severe SARS-CoV-2 infection. All adverse events detected in 23 patients in the Intensive Care Unit between March 15 and June 15, 2020 were registered. We describe type and severity of the adverse events and if treatment suspension was needed. The results show a high rate of adverse events (10/23, 43%) in treatment with lopinavir/ritonavir. In most cases early treatment suspension was required. Even though the limitations of our study derived from the small sample size, these results could help in building evidence about the safety of using lopinavir/ritonavir for severe SARS-CoV-2 infection.

Miopatía por estatinas y vitamina D / Statin-Related Myopathy and Vitamin D

Las estatinas son fármacos habitualmente seguros y bien tolerados, muy eficaces para la prevención de trastornos cardiovasculares. La presencia de mialgias, poco frecuente, pero con incidencia dispar en diversos reportes, es una de las causas de abandono de su uso. También las distintas denominaciones (mialgia, miopatía, rabdomiólisis) y la subjetividad de cada paciente para referirlas han creado confusión en el tema. Se ha comenzado a reportar asociación entre niveles de vitamina D sérica disminuida y mayor riesgo de miopatía, por un lado, y trabajos donde pacientes que las abandonaban a causa de mialgias, con deficiencia de vitamina D, pueden tolerarlas una vez que se suplementa la vitamina hasta valores deseables. La presencia de polimorfismos en genes de enzimas que metabolizan o transportan a las estatinas es otro factor claramente relacionado con miopatía. Es posible que el déficit de vitamina D deba ser considerado un factor de riesgo para desarrollar miopatía por estatinas, como lo serían también la administración simultánea de fármacos que se metabolizan por la misma vía de citocromo P450, o la presencia de los polimorfismos mencionados. En conclusión, el hallazgo de tener deficiencia de vitamina D se asocia a miopatía por estatinas, o que es un factor de riego para desarrollarla, abre nuevas perspectivas para un gran número de pacientes que abandonan este tratamiento debido a esta patología. (AU)

Statins are usually safe and well tolerated drugs, very effective for preventing cardiovascular complications. The rare presence of myalgia, with different incidence as reported by several studies, is one of the causes of lack of drug compliance. Also the different symptoms referred (myalgia, myopathy, rhabdomyolysis) and the lack of objetivity of each patient when referring to the symptoms, have created confusion in this matter. Associations between decreased vitamin D levels and increased risk of myopathy has been reported. Indeed, studies describing patients with vitamin D deficiency who are not compliant due to myalgia show that they become tolerant to the drugs once the vitamin is supplemented to desirable values. The presence of gene polymorphisms for enzymes that metabolize or transport statins is another factor clearly related to myopathy. Therefore, we should consider vitamin D deficiency and other conditions such as the simultaneous administration of drugs that are metabolized by the same cytochrome P450 pathway, or the presence of mentioned polymorphisms as a risk factor for developing myopathy due to statins. In conclusion, the finding that vitamin D deficiency is associated with statin myopathy, or is a risk factor its develpoment, opens new perspectives for a large number of patients who leave this treatment due to this condition. (AU)

Effects of Ayurvedic Rasayana botanicals on CYP3A4 isoenzyme system / 中西医结合学报

<p><b>OBJECTIVE</b>Consuming botanical dietary supplements or herbal drugs along with prescription drugs may lead to potential pharmacokinetic-pharmacodynamic (PK-PD) herb-drug interactions (HDI). The present study focuses on the importance of and novel approach for assessing HDI in integrative medicine with case examples of two frequently-used Ayurvedic Rasayana botanicals.</p><p><b>METHODS</b>The aqueous extracts of Asparagus racemosus (ARE) and Gymnema sylvester (GSE) were prepared as per Ayurvedic Pharmacopoeia of India. Chemoprofiling of these extracts was done using high-performance liquid chromatography (HPLC). Additionally, ARE was characterized for the presence of shatavarins IV and I using HPLC & mass spectroscopy respectively. Effects of ARE and GSE were investigated on rat liver microsome using testosterone probe drug assay. The changes in formation of metabolite (6-β hydroxy testosterone) were monitored on incubation of testosterone alone, testosterone with ketoconazole, ARE and GSE using HPLC. Half inhibitory concentration (IC50) was used to predict plausible HDI.</p><p><b>RESULTS</b>ARE and GSE showed no inhibition with IC50 values >1 000 μg/mL while the standard inhibitor ketoconazole completely abolished CYP3A4-dependent activity at 0.531 μg/mL and IC50 was found to be 0.036 μg/mL.</p><p><b>CONCLUSION</b>ARE and GSE prepared as per Ayurvedic Pharmacopoeia of India were found to be safe for CYP3A4-mediated inhibitory HDI in rats. Our in vitro study suggests the need of further in vivo investigation for HDI in order to provide clinical relevance.</p>

Effects of triptolide on the pharmacokinetics of cyclophosphamide in rats: a possible role of cytochrome P3A4 inhibition / 中国结合医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of a 10-day course of triptolide (TP) on rat cytochrome (CY) P3A4 activity, and on the pharmacokinetics of cyclophosphamide (CPA).</p><p><b>METHODS</b>In the pharmacokinetics experiment, rats were orally given 0.9% NaCl solution (n=5) and TP [1.2 (mg/kg·d)] for 10 days and a single dose of CPA was administered intravenously (100 mg/kg) to rats on day 11. Blood samples were collected up to 4 h at predetermined time intervals, the plasma concentration of CPA was determined by high performance liquid chromatography (HPLC) and pharmacokinetic parameters were determined. In the in vitro CYP3A4 activity inhibition research, rat blank liver microsomes were divided into 3 groups: a control group, a TS (5 μL, 200 μmol/L) with TP (5 μL, 12.5 μmol/L) group, a TS with ketoconazole (5 μL, 1 μmol/L) group. Concentration of 6β-hydroxylated testosterone (6β-OHT) in liver microsomes was measured by HPLC and the activity of CYP 3A4 was calculated through the following formula: Einhibitor/Econtrol × 100%=Cinhibitor/Ccontrol × 100%.</p><p><b>RESULTS</b>Compared with the control group, the area under the plasma concentration-time curve (AUC0-∞) of CPA was significantly increased by 229.05% pretreated with TP (P<0.01). Peak plasma concentrations (Cmax) of CPA was significantly increased and plasma half-life was correspondingly extended. The CYP3A4 activity was significantly inhibited by ketoconazole 93.5%±0.2% and TP 84.6%±0.3% compared with the control group (P<0.01 and P<0.05, respectively).</p><p><b>CONCLUSION</b>Our results strongly suggested that long-term oral intake of TP can distinctly inhibit the CYP3A4 activity and this inhibition evidently decrease the formation of toxic metabolites of CPA.</p>

Meta-Analysis of First-Line Triple Therapy for Helicobacter pylori Eradication in Korea: Is It Time to Change?

Proton pump inhibitor (PPI)-based triple therapy consisting of PPI, amoxicillin, and clarithromycin, is the recommended first-line treatment for Helicobacter pylori infection. However, the eradication rate of triple therapy has declined over the past few decades. We analyzed the eradication rate and adverse events of triple therapy to evaluate current practices in Korea. A comprehensive literature search was performed up to August 2013 of 104 relevant studies comprising 42,124 patients. The overall eradication rate was 74.6% (95% confidence interval [CI], 72.1%-77.2%) by intention-to-treat analysis and 82.0% (95% CI, 80.8%-83.2%) by per-protocol analysis. The eradication rate decreased significantly from 1998 to 2013 (P < 0.001 for both intention-to-treat and per-protocol analyses). Adverse events were reported in 41 studies with 8,018 subjects with an overall incidence rate of 20.4% (95% CI, 19.6%-21.3%). The available data suggest that the effectiveness of standard triple therapy for H. pylori eradication has decreased to an unacceptable level. A novel therapeutic strategy is warranted to improve the effectiveness of first-line treatment for H. pylori infection in Korea.

Metabolites and metabolic pathways of mesaconitine in rat liver microsomal investigated by using UPLC-MS/MS method in vitro / 药学学报

Mesaconitine was incubated with rat liver microsomes in vitro. The metabolites of mesaconitine in rat liver microsomes were identified by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method with high resolution power. A typical reaction mixture of 100 mol L-1 Tris-HCI buffer (pH 7.4) containing 0.5 gL-1 microsomal protein and 50 micro molL-1 mesaconitine was prepared. The above reaction mixture was divided into six groups, and the volume of each group was 200 micro L. The incubation mixture was pre-incubated at 37 degrees C for 2 min and the reactions were initiated by adding NADPH generating system. After 90 min incubation at 37 degrees C, 200 micro L of acetonitrile was added to each group to stop the reaction. The metabolites of mesaconitine were investigated by UPLC-MS/MS method. Mesaconitine and 6 metabolites M1-M6 were found in the incubation system. The structures were characterized according to the data from MS/MS spectra and literatures. The metabolic reactions of mesaconitine in rat liver microsomes included the demethylation, deacetylation, dehydrogenation and hydroxylation. The major metabolic pathways of mesaconitine in rat liver microsomes were determined by UPLC-MS/MS on multiple reaction monitoring (MRM) mode combined with specific inhibitors of cytochrome P450 (CYP) isoforms, including alpha-naphthoflavone (CYP1A2), quinine (CYP2D), diethyldithiocarbamate (CYP2E1), ketoconazole (CYP3A) and sulfaphenazole (CYP2C), separately. Mesaconitine was mainly metabolized by CYP3A. CYP2C and CYP2D were also more important CYP isoforms for the metabolism reactions of mesaconitine, but CYP1A2 and CYP2E1 haven't any contribution to MA metabolism in rat liver microsomes.

Inhibitory effect of PNS on drug metabolism enzyme CYP3A in rat livers and its kinetic analysis / 中国中药杂志

<p><b>OBJECTIVE</b>To study the inhibitory effect of total saponins of the root and rhizome of Panax notoginseng (PNS) on drug metabolism enzyme CYP3A in rat livers and its kinetic analysis.</p><p><b>METHOD</b>Microsome enzyme was prepared by differential velocity centrifugation. Michaelis constant (Km) and maximum velocity (Vmax) of CYP3A, 50% inhibitory concentration of PNS on CYP3A, and the inhibition type and the inhibition constant of CYP3A (Ki, Kis) of PNS on CYP3A were calculated by Lineweaver-Burk and the low of semi-effect-probit.</p><p><b>RESULT</b>Total saponins of the root and rhizome of panax notoginseng inhibited CYP3A activity, with IC50 of 689.54 mg x L(-1). Compared with the substrate aminopyrine, CYP3A showed Km of 0.036 mmol x L(-1) and Vmax of 21.01 micromol min(-1) x g(-1). Total saponins of the root and rhizome of panax notoginseng showed a mixed inhibition on CYP3A, with the inhibition constants of 247.79 mg x L(-1) (Ki) and 321.79 mg x L(-1) (Kis).</p><p><b>CONCLUSION</b>Total saponins of the root and rhizome of panax notoginseng have a significant effect on CYP3A activity in rat livers.</p>

In vitro inhibition of five traditional Chinese medicine injections on rat liver microsomal CYP3A / 中国中药杂志

<p><b>OBJECTIVE</b>Qingkailing injection (QKLI), Jinnaduo injection (JNDI), Shuxuetong injection (SXTI), Shenmai injection (SMI) and Kangai injection (KAI) are widely used in China. To predict the herb-drug interactions in clinical application, they were evaluated for their in vitro inhibition effect on CYP3A in rat liver microsomes.</p><p><b>METHOD</b>The rat liver microsomes were incubated with different doses of 5 kinds of traditional Chinese medicine injections (TCMIs) in the present of testosterone, a specific substrate of CYP3A. 6beta-hydroxytestosterone, the metabolite of testosterone, was monitored by HPLC to compare the inhibition effect of 5 TCMIs on CYP3A in rat liver microsomes. Ketoconazole was used as a positive control.</p><p><b>RESULT</b>10% QKLI reduced the formation of 6beta-hydroxytestosterone by approximately 93.0%, which is more significant than other four TCMIs. The half maximal inhibitory concentration (IC50) and the enzyme-inhibitor constant K(i) were 1.0% and 0.7% respectively.</p><p><b>CONCLUSION</b>QKLI showed much stronger inhibition activity against CYP3A, comparing to other 4 TCMIs. The results revealed that QKLI may be involved in herb-drug interactions by inhibition of CYP3A.</p>

In vitro metabolism of glycyrrhetic acid by human cytochrome P450 / 药学学报

Licorice root has been frequently used as antitode in traditional Chinese medicine. As the main active component of Licorice root, glycyrrhetic acid (GA) is mainly metabolized in liver. This study was designed to investigate the in vitro metabolism of GA by human liver microsomes (HLM) and human recombinant cytochrome P450 (CYP) isoforms. The results indicated that GA was metabolized mainly by CYP3A4. The K(m), V(max) and CL(int) of GA in HLM were 18.6 micromol x L(-1), 4.4 nmol x mg(-1) (protein) x min(-1) and 0.237 mL x mg(-1) (protein) x min(-1), respectively. At concentration up to 50 micromol x L(-1), GA inhibited CYP2C19, CYP2C9 and CYP3A4 enzyme activities with the inhibitory potencies up to 50%.

Metabolism of 3-cyanomethyl-4-methyl-DCK, a new anti-HIV candidate, in human intestinal microsomes / 药学学报

The biotransformation, CYP reaction phenotyping, the impact of CYP inhibitors and enzyme kinetics of 3-cyanomethyl-4-methyl-DCK (CMDCK), a new anti-HIV preclinical candidate belonging to DCK analogs, were investigated in human intestinal microsomes and recombinant cytochrome P450 (CYP) enzymes. CMDCK (4 micromol L(-1)) was incubated with a panel of rCYP enzymes (CYP1A2, 2C9, 2C19, 2D6 and 3A4) in vitro. The remaining parent drug in incubates was quantitatively analyzed by a LC-MS method. CYP3A4 was identified as the principal CYP isoenzyme responsible for its metabolism in intestinal microsomes. The major metabolic pathway of CMDCK was oxidation and a number of oxidative metabolites were screened with LC-MS. The Km, Vmax, CLint and T1/2 of CMDCK obtained from human intestinal microsome were 45.6 micromol L(-1), 0.33 micromol L(-1) min(-1), 12.1 mL min(-1) kg(-1) and 25.7 min, respectively. Intestinal clearance of CMDCK was estimated from in vitro data to be 3.3 mL min(-1) kg(-1), and was almost equal to the intestinal blood flow rate (4.6 mL min(-1) kg(-1)). The selective CYP3A4 inhibitors, ketoconazole, troleandomycin and ritonavir demonstrated significant inhibitory effects on CMDCK intestinal metabolism, which suggested that co-administration of CMDCK with potent CYP3A inhibitors, such as ritonavir, might decrease its intestinal metabolic clearance and subsequently improve its bioavailability in body.

Quantitative prediction of in vivo drug-drug interactions based on in vitro inhibition or/and induction data for CYP3A4 / 药学学报

Inhibition or/and induction of CYP3A4 are the major mechanisms underlying the common clinical drug-drug interactions, which has been gained attention in new drug discovery and development as well as clinical practice. Quantitative prediction of drug-drug interactions at the early stage of drug development is advantageous for reducing the cost and duration of development and providing more information for the later clinical studies. The review summarizes the update progress on quantitative prediction of in vivo drug-drug interactions derived from models based on in vitro inhibition or/and induction for CYP3A4.

Effect of CYP3A and P-glycoprotein on the absorption of buagafuran in rat intestinal lumen / 药学学报

The rat single-pass intestinal perfusion model was applied to study the effect of CYP3A and P-glycoprotein on the absorption of buagafuran in lumen of rats. Buagafuran concentrations in intestinal perfusate and blood in vena mesenterica collected at different time points after perfusion were determined by GC-MS. Permeability coefficient of buagafuran was calculated by the equation [P(lumen) = -(Q/2pirl)Ln(C(out)/C(in)) and P(blood) = (deltaM(B)/deltat)/(2pirl<C>)]. The effects of troleandomycin (TAO, CYP3A inhibitor), cyclosporin A (CYP3A/p-glycoprotein inhibitor) on the absorption of buagafuran in lumen were observed. After rat single-pass intestinal perfusion, the cumulative amount of buagafuran in mesenteric vein of rat was 73.4, 82.9, and 98.3 pmol x cm(-2) and were increased 3.9, 4.6, and 5.6 fold by addition of inhibitor of P-gp (LSN335984), CYP3A (TAO) or P-gp and CYP3A (CsA), respectively. Moreover, the metabolized fraction of buagafuran was decreased by 12%, 11% and 21% with inhibitors. The results suggested that the poor bioavailability of buagafuran was mostly due to the interplay of P-gp and CYP3A on the absorption, transport and metabolism of buagafuran in intestine of rats.

A limited sampling strategy of phenotyping probe midazolam to predict inhibited activities of hepatic CYP3A in rats / 药学学报

The present study was to evaluate feasibility of a limited sampling strategy (LSS) in the prediction of inhibited hepatic CYP3A activity with systemic clearance of midazolam (MDZ), a hepatic CYP3A activity phenotyping probe. Rats were pretreated with a serial doses of ketoconazole, a selective inhibitor on CYP3A. Blood samples were collected and detected for MDZ at specified time points after intravenous injection of MDZ. Stepwise regression analysis and a Jack-knife validation procedures were performed in one group of rats as training set to establish the most informative LSS model for accurately estimating the clearance of MDZ. Another group of rats with same treatment was used as validation set to estimate the individual clearance based on predictive equations derived from the training set. Bland-Altman plots showed a good agreement between the systemic clearance calculated from DAS (CLobs) and corresponding parameter that was derived from three LSS models (CLest). LSS models derived from two or three sampling time points, including 60, 90 min, 30, 60, 90 min and 30, 60, 120 min, exhibited a good accuracy and acceptable error for estimating the CLobs of MDZ to evaluate hepatic CYP3A activity, especially the 60, 90 min LSS model is most accurate and convenient. The results supported that limited plasma sampling to predict the systemic clearance of MDZ is easier than the usual method for estimating CYP3A phenotyping when the hepatic activity of CYP3A is reduced in the rat. The present study provided theoretical basis and laboratory evidence for LSS to clinically evaluate metabolizing function of liver and

Effects of the flavonoids on cytochrome P-450 CYP1, 2E1, 3A4 and 19 / 药学学报

Flavonoids are present in fruits, vegetables and beverages derived from plants, and in many dietary supplements or herbal remedies. A number of naturally occurring flavonoids have been shown to modulate the CYP450 system, including the induction or inhibition of these enzymes. This review focuses on the flavonoid effects on cytochrome P450 (CYP) enzyme CYP1, 2E1, 3A4 and 19. Flavonoids alter CYPs by various mechanisms, including the stimulation of gene expression via specific receptors and/or CYP protein, or mRNA stabilization and so on. But in vivo and in vitro, the effects of flavonoids are not always coincident as a result of concentrations of flavonoids, genetic and environmental factors. As well, flavonoids may interact with drugs through the induction or inhibition of their metabolism. Much attention should be paid to the metabolism interaction of the flavonoids when coadministered with other drugs.

Characteristics of uptake, transport and efflux of Z- and E-ajoenes in Caco-2 cell monolayers in vitro / 药学学报

The characteristics of uptake, transepithelial transport and efflux of Z- and E-ajoenes isolated from the bulbs of Allium sativum were studied. A human colon cell model Caco-2 cell monolayers in vitro cultured had been applied to study the characteristics of uptake, transepithelial transport and efflux of Z- and E-ajoenes. The quantitative determination of Z- and E-ajoenes was performed by high-performance liquid chromatography. Z- and E-Ajoenes can be detected only in the apical side and can be metabolized, but both compounds can not be transported from apical-to-basolateral and basolateral-to-apical directions in cultured Caco-2 cell monolayers. The metabolism of Z- and E-ajoenes in Caco-2 cell monolayers can be partially inhibited by vitamin C as an anti-oxidant, metyrapone as an inhibitor to subtype CYP3A of cytochrome P450 drug metabolism enzymes, and sodium azide as an inhibitor to ATP production. It is shown that neither Z-ajoene nor E-ajoene can pass through Caco-2 cell monolayers, and that they can be metabolized by the cells. The metabolism might be in correlation with cytochrome P450 drugs metabolism enzymes in Caco-2 cell monolayers.

Study on metabolism of tetramethylpyrazine in system of rat liver microsomes / 中国中药杂志

<p><b>OBJECTIVE</b>The metabolic character of tetramethylpyrazine (TMPz) in rat liver microsomes was studied in vitro and in vivo to identify which isoforms of cytochrome P450 were responsible for TMPz metabolism in rats, offer the theoretical foundation for the fact that it is rational to use medicine in clinic.</p><p><b>METHOD</b>Set up UV- HPLC method of TMPz, determine concentration of TMPz and its formation in rat plasma and liver microsomes incubation solution, analyze the correlation between TMPz's metabolic eliminate rate and each inducer. Erythromycin( ERY) N-demethylase activity of each sample in rat liver microsomes was measured using N-demethylation reaction of ERY as probe. The correlation between the rate of TMPz metabolite formation and the demethylase activity was analysed. After the SD rats who had been treated with inducer, inhibitor, or untreated, received administration of TMPz in vein, the plasma concentration of TMPz were determined by HPLC. Pharmacokinetic parameters of TMPz were computed and compared.</p><p><b>RESULT</b>The disppearing rate of TMPz in the incubation solutions of the rats liver microsomes, which treated with DEX, were markedly quicker than that of control group (P < 0. 01) , while no obvious difference between P-NF group or PB and control group was observed (P > 0. 05). The activity of ERY-N-demethylase in DEX-induced group was corespondingly enhanced, was much higer than that in control group. The correlation between the rate of TMPz metabolic product formation and the activity of N-demethylase was significant. After using Ket, the CYP3A inhibitor, the metabolism of TMPz could be significantly inhibited the metabolism of TMPz in rat liver microsomes. In vivo, CL( s) were larger than that of the control group,t,/2 were smaller than the control group in DEX group; By contrary, CL(s) was smaller than the control group,t1/2 was larger than the control group in Ket group.</p><p><b>CONCLUSION</b>Results suggest that CYP3A plays a major role in TMPz metabolism in rats, TMPz lie in the possibility of Interaction among the medicines between TMPz and CYP3A inducers or inhibitors when they are used in clinic.</p>

Metabolic kinetics of MN9202 in Beagle dog liver microsomes / 药学学报

<p><b>AIM</b>To study the metabolic kinetics of MN9202 in Beagle dog liver microsome.</p><p><b>METHODS</b>Beagle dog liver microsomes were prepared by using ultracentrifuge method. After incubating 0.4 micromol x L(-1) MN9202 with 1 g x L(-1) microsomes for 30 min at 37 degrees C, the reaction was terminated by adding 0.5 mL alkalization. The RP-HPLC was used to determine the drug in the incubation mixture. The Michaelis-Menten parameters Km, and Vmax in Beagle dog liver microsomes were initially estimated by analyzing Lineweave-Brurk plot. Various selective CYP inhibitors were used to investigate their inhibitory effect on the metabolism of MN9202.</p><p><b>RESULTS</b>The Km, Vmax and CLint of MN9202 were (22.6 +/- 8.0) micromol x L(-1), (0.54 +/- 0.17) micromol x g(-1) x min(-1) and (0.0242 +/- 0.0009) L x g(-1) x min(-1), respectively. The metabolism of MN9202 was significantly inhibited by ketoconazole (Ket) and troleandomycin (Tro) in Beagle dog liver microsomes. Tranylcypromine (Tra) could inhibit the metabolism of drug as well. While other inhibitors showed little inhibitory effect on the metabolism of MN9202.</p><p><b>CONCLUSION</b>It was shown that CYP3A and CYP2C19 were involved in MN9202 metabolism. The inhibitors of human CYP3A and CYP2C19 may have potential interaction with MN9202, and this can reduce the metabolism rate and increase the toxicity of MN9202.</p>