RESUMO
1. Aspirin (ASA) and clopidogrel (CLP) are used in combination as dual antiplatelet therapy (DAPT) for acute coronary syndrome based on their complementary mechanisms for platelet aggregation inhibition. However, the pharmacokinetics of such drug combination usage has not been thoroughly investigated. 2. In the current study, an LC-MS/MS method was developed to simultaneously determine the plasma concentrations of ASA and its metabolite salicylic acid (SA) with CLP and its metabolites, clopidogrel carboxylic acid (CLPM) and clopidogrel active metabolite derivative (CAMD). The pharmacokinetics of ASA, SA, CLP, CLPM and CAMD in rats receiving two-week DAPT with ASA and CLP were then determined. 3. After two-week DAPT with ASA and CLP in rats, the activities of aspirin esterase and rCyp2c11, enzymes mediating rat metabolism of ASA and CLP, respectively, in prepared rat liver microsomes were measured followed by further determination of rCyp2c11 mRNA expressions. The results demonstrated that DAPT led to minimal impact on aspirin esterase activity but significant decrease in rCyp2c11 activity and mRNA expression. 4. In conclusion, our findings on impairment in rCyp2C11 activity and mRNA expression by DAPT in rats could provide guidance on its safe clinical use with other CYP 2C19 substrates.
Assuntos
Hidrocarboneto de Aril Hidroxilases/metabolismo , Aspirina/farmacocinética , Família 2 do Citocromo P450/metabolismo , Fígado/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Esteroide 16-alfa-Hidroxilase/metabolismo , Ticlopidina/análogos & derivados , Animais , Hidrocarboneto de Aril Hidroxilases/genética , Aspirina/sangue , Cromatografia Líquida/métodos , Clopidogrel , Família 2 do Citocromo P450/genética , Inativação Metabólica , Fígado/metabolismo , Masculino , Inibidores da Agregação Plaquetária/farmacocinética , Ratos Sprague-Dawley , Ácido Salicílico/metabolismo , Esteroide 16-alfa-Hidroxilase/genética , Espectrometria de Massas em Tandem/métodos , Ticlopidina/sangue , Ticlopidina/farmacocinéticaRESUMO
1. Determination of fm, CYP for a compound is critical to assess the potential risk of a drug candidate as a victim of DDI. Several compounds are identified as CYP2B6 substrates, but the fm, CYP2B6 values are not determined quantitatively. 2. Two methods of reaction phenotyping, the chemical inhibition method and metabolism in rCYP enzymes, were used to determine the relative contributions of the enzymes. Chemical inhibition method was also conducted in the presence of BSA (0.5% w/v). 3. The results confirm with the earlier studies concerning the identity of the CYP2B6 enzyme. The fm, CYP2B6 values for artemisinin, bupropion, clopidogrel, ketamine, selegiline, sertraline and ticlopidine were 0.24, 0.28, 0.15, 0.45, 0.46, 0.42 and 0.54, respectively, in HLM determined by chemical inhibition method. The fm, CYP2B6 values for artemisinin, bupropion, clopidogrel, ketamine, selegiline, sertraline and ticlopidine were 0.46, 0.17, 0.15, 0.60, 0.51, 0.66 and 0.77, respectively, in HLM determined by chemical inhibition method in the presence of BSA (0.5% w/v). 4. Bupropion metabolism is majorly mediated by CYP2C19 (0.41) with a minor contribution from CYP2B6 (0.16) in the presence of BSA. Ticlopidine is a time-dependent inhibitor of both CYP2B6 and CYP2C19 that can inhibit the bupropion metabolism by 50-60%.
Assuntos
Citocromo P-450 CYP2B6/metabolismo , Interações Medicamentosas , Animais , Área Sob a Curva , Biomarcadores/metabolismo , Bovinos , Ativação Enzimática/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Isoenzimas/metabolismo , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Fenótipo , Proteínas Recombinantes/metabolismo , Soroalbumina Bovina/metabolismo , Especificidade por Substrato/efeitos dos fármacos , Ticlopidina/sangue , Ticlopidina/farmacocinética , Fatores de TempoRESUMO
This study evaluated the effects of Newbouldia laevis and Cassia abbreviata extracts on CYP450 enzyme activity. Recombinant CYP450 enzyme and fluorogenic substrates were used for evaluating inhibition, allowing the assessment of herb-drug interactions (HDI). Phytochemical fingerprinting was performed using UPLC-MS. The herbal extracts were risk ranked for HDI based on the IC50 values determined for each CYP enzyme. Newbouldia laevis inhibited CYP1A2, CYP2C9, and CYP2C19 enzyme activities with Ki of 2.84 µg/mL, 1.55 µg/mL, and 1.23 µg/mL, respectively. N. laevis exhibited a TDI (4.17) effect on CYP1A2 but not CYP2C9 and CYP2C19 enzyme activities. Cassia abbreviata inhibited CYP1A2, CYP2C9, and CYP2C19 enzyme activities showing a Ki of 4.86 µg/mL, 5.98 µg/mL, and 1.58 µg/mL, respectively. TDI potency assessment for Cassia abbreviata showed it as a potential TDI candidate (1.64) for CYP1A2 and CYP2C19 (1.72). UPLC-MS analysis showed that Newbouldia laevis and Cassia abbreviata possess polyphenols that likely give them their therapeutic properties; some of them are likely to be responsible for the observed inhibition. The observations made in this study suggest the potential for these herbal compounds to interact, especially when co-administered with other medications metabolized by these CYP450 enzymes.
Assuntos
Cassia/química , Inibidores das Enzimas do Citocromo P-450/química , Inibidores das Enzimas do Citocromo P-450/farmacologia , Lamiales/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Disponibilidade Biológica , Cromatografia Líquida de Alta Pressão , Inibidores das Enzimas do Citocromo P-450/farmacocinética , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Interações Ervas-Drogas , Humanos , Concentração Inibidora 50 , Cinética , Espectrometria de Massas , Estrutura Molecular , Extratos Vegetais/farmacocinética , Distribuição TecidualRESUMO
In the present study, the metabolism of ritonavir was explored in the presence of rCYP3A4 using a well-established strategy involving liquid chromatography-mass spectrometry (LC-MS) tools. A total of six metabolites were formed, of which two were new, not reported earlier as CYP3A4-mediated metabolites. During LC-MS studies, ritonavir was found to fragment through six principal pathways, many of which involved neutral loss of CO2, as indicated through 44-Da difference between masses of the precursors and the product ions. This was unusual as the drug and the precursors were devoid of a terminal carboxylic acid group. Apart from the neutral loss of CO2, marked differences were also observed among the fragmentation pathways of the drug and its metabolites having intact N-methyl moiety as compared to those lacking N-methyl moiety. These unusual fragmentation behaviours were successfully explained through energy distribution profiles by application of the density functional theory.