Investigating herb–drug interactions: the effect of Citrus aurantium fruit extract on the pharmacokinetics of amiodarone in rats

Citrus aurantium extract has been largely used in weight loss and sports performance dietary supplements. However, the safety of C. aurantium-containing products has been questioned mainly due to the association of its use with adverse events in the cardiovascular system. Therefore, this work aimed to assess the potential for herb–drug interactions among a standardized C. aurantium extract (GMP certificate) and amiodarone (narrow therapeutic index drug) in rats. In a first pharmacokinetic study, rats were simultaneously co-administered with a single-dose of C. aurantium (164 mg/kg, p.o.) and amiodarone (50 mg/kg, p.o.); in a second study, rats were pre-treated during 14 days with C. aurantium (164 mg/kg/day, p.o.) and received amiodarone (50 mg/kg, p.o.) on the 15th day. Rats of the control groups received the corresponding volume of vehicle. Overall, after analysis of the pharmacokinetic data, it deserves to be highlighted the significant increase of the peak plasma concentration of amiodarone in rats pre-treated with C. aurantium extract, while the extent of systemic exposure was comparable between both groups. This paper reports, for the first time, data on the potential of herb–drug interaction between C. aurantium extract and amiodarone. However, specific clinical trials should be performed to confirm these results in humans

A Rapid and Sensitive HPLC–DAD Assay to Quantify Lamotrigine, Phenytoin and Its Main Metabolite in Samples of Cultured HepaRG Cells

A sensitive and fast high-performance liquid chromatography-diode-array detection assay was developed and validated for the simultaneous quantification of 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH), phenytoin (PHT) and lamotrigine (LTG) in samples of cultured HepaRG cells. Chromatographic separation of analytes and internal standard (IS) was achieved in ∼15 min on a C18-column, at 35°C, using acetonitrile (6%), methanol (25%) and a mixture (69%) of water-triethylamine (99.7:0.3, v/v; pH 6.0), pumped at 1 mL/min. The analytes and IS were detected at 215 or 235 nm. Calibration curves were linear with regression coefficients >0.994 over the concentration ranges of 0.1-15 µg/mL for HPPH; 0.15-30 µg/mL for PHT and 0.2-20 µg/mL for LTG. The method showed to be accurate (bias value of ±10.5 or ±17.6% in the lower limit of quantification, LLOQ) and precise (coefficient variation ≤8.1 or ≤15.4% in the LLOQ), and the absolute recovery of the analytes ranged from 62.5 to 96.9%. HepaRG cells have emerged as a very promising in vitro model to evaluate metabolic, drug interaction and/or pharmacokinetic studies, and this methodology will be suitable to support subsequent studies involving the antiepileptic drugs PHT and LTG

Effects of Paullinia cupana extract on lamotrigine pharmacokinetics in rats: A herb-drug interaction on the gastrointestinal tract with potential clinical impact.

Paullinia cupana-containing preparations are being consumed worldwide for weight reduction. As obesity and epilepsy are common comorbidities and lamotrigine (LTG) is a broad-spectrum antiepileptic drug, it is likely to find epilepsy patients taking P. cupana and LTG simultaneously. Thus, this work aimed to investigate the potential interaction between P. cupana extract and LTG in rats. In a study, rats were orally co-administered with a single-dose of P. cupana extract (821 mg/kg) and LTG (10 mg/kg). In another study, rats were orally pre-treated for 14 days with P. cupana extract (821 mg/kg/day) receiving LTG (10 mg/kg, p.o.) on the 15th day. Rats of the respective control groups received the corresponding volume of the extract vehicle. LTG concentrations were determined at several post-dose time-points and submitted to a non-compartmental pharmacokinetic analysis. The co-administration of P. cupana and LTG induced a significant reduction of LTG Cmax and AUC0-24 and prolonged the mean residence time. However, no significant effects were observed on LTG pharmacokinetics following a 14-day pre-treatment period with the extract. In this study changes in the body weight of rats and in some biochemical parameters were also evaluated. Overall, the results revealed a pharmacokinetic-based herb-drug interaction between P. cupana extract and LTG, mainly after their co-administration

Influence of the dual combination of silymarin and (-)-epigallocatechin gallate, natural dietary flavonoids, on the pharmacokinetics of oxcarbazepine in rats

Considering the potential of flavonoids in reversing the P-glycoprotein (P-gp)–mediated multidrug resistance, this work aimed to assess the combined effects of silymarin and (-)-epigallocatechin gallate (EPG) on the pharmacokinetics of the P-gp substrates oxcarbazepine (OXC) and licarbazepine (LIC). Rats were pre-treated intraperitoneally with silymarin (25 mg/kg), EPG (25 mg/kg), silymarin/EPG (12.5/12.5 mg/kg; 6.25/18.75 mg/kg; 18.75/6.25 mg/kg) or verapamil (25 mg/kg, reference P-gp inhibitor) before the intraperitoneal administration of OXC (50 mg/kg). Pre-treatment with dual silymarin/EPG combinations originated peak plasma concentrations of OXC and LIC (pharmacologically active metabolite of OXC) similar to those achieved in the presence of verapamil (positive control). Moreover, the effects promoted by silymarin/EPG combinations on the magnitude of systemic drug exposure to OXC and LIC were also reflected in the corresponding drug levels attained in the brain (biophase). These findings evidence the synergistic effect of silymarin and EPG in enhancing the degree of systemic exposure to OXC and LIC in rats, which occurred in a comparable extent to that observed with verapamil. Hence, our findings support the combination of flavonoid-type P-gp inhibitors and P-gp substrate antiepileptic drugs as a potential therapeutic strategy for the management of pharmacoresistant epilepsy.The authors are grateful to FCT - Foundation for Science and Technology (Lisbon, Portugal) for the PhD fellowship of Ana Ferreira (SFRH/BD/84936/2012). This work was also supported by FEDER funds through the POCI - COMPETE 2020 - Operational Programme Competitiveness and Internationalization in Axis I - Strengthening research, technological development and innovation (Project POCI-01-0145-FEDER-007491) and National Funds by FCT (Project UID/Multi/00709/2013)

Flavonoid compounds as reversing agents of the P-glycoprotein-mediated multidrug resistance: An in vitro evaluation with focus on antiepileptic drugs

The pharmacoresistance to antiepileptic drugs (AEDs) remains a major unsolved therapeutic need. The overexpression of multidrug transporters, as the P-glycoprotein (P-gp), at the level of the blood-brain barrier of epileptic patients has been suggested as a key mechanism underlying the refractory epilepsy. Thus, efforts have been made to search for therapeutically useful P-gp inhibitors. Herein, the strategy of flavonoid/AED combined therapy was exploited as a possible approach to overcome the P-gp-mediated pharmacoresistance. For this purpose, several in vitro studies were performed using Madin-Darby canine kidney II (MDCK II) cells and those transfected with the human multidrug resistance-1 (MDR1) gene, overexpressing the P-gp (MDCK-MDR1). Overall, the results showed that baicalein, (−)-epigallocatechin gallate, kaempferol, quercetin and silymarin, at 200 μM, produced a marked increase on the intracellular accumulation of rhodamine 123 in MDCK-MDR1 cells, potentially through inhibiting the P-gp activity. In addition, with the exception of lamotrigine, all other AEDs tested (phenytoin, carbamazepine and oxcarbazepine) and their active metabolites (carbamazepine-10,11-epoxide and licarbazepine) demonstrated to be P-gp substrates. Furthermore, the most promising flavonoids as Pgp inhibitors promoted a significant increase on the intracellular accumulation of the AEDs (excluding lamotrigine) and their active metabolites in MDCK-MDR1 cells, evidencing to be important drug candidates to reverse the AED-resistance. Thus, the co-administration of AEDs with baicalein, (−)-epigallocatechin gallate, kaempferol, quercetin and silymarin should continue to be explored as adjuvant therapy for refractory epilepsy

Determination of lamotrigine in human plasma and saliva using microextraction by packed sorbent and high performance liquid chromatography–diode array detection: An innovative bioanalytical tool for therapeutic drug monitoring

A ground-breaking high-performance liquid chromatography-diode array detection method based on microextraction by packed sorbent (MEPS) as sample preparation approach is described herein for determination of lamotrigine (LTG), a narrow therapeutic index drug, in human plasma and saliva. MEPS variables and chromatographic conditions were optimized to achieve appropriate selectivity and sensitivity using small sample volumes (100 μL). The chromatographic separation of LTG and chloramphenicol [internal standard (IS)] was accomplished in < 5 min on a C18-column, at 35 °C, using a mobile phase composed by acetonitrile/methanol/water-triethylamine 0.3% at pH 6.0 (13:13:74, v/v/v) pumped isocratically at 1 mL/min. LTG and IS were detected at 215 nm. A good linearity was obtained for LTG (r² ≥ 0.9936) in the range of 0.1–20 μg/mL in plasma and saliva, with the limit of quantification of 0.1 μg/mL. The method was shown to be precise (RSD ≤ 14.5%) and accurate (bias ± 13.4%), and the absolute recovery ranged from 64.9% to 73.6%. The stability of LTG was demonstrated in plasma and saliva samples in all studied conditions. The proposed assay was applied to the analysis of real human plasma and saliva samples from epilepsy patients under LTG therapy and the results support its usefulness for therapeutic drug monitoring

Development and application of an ex vivo fosphenytoin nasal bioconversion/permeability evaluation method

There is an increasing interest in the intranasal delivery of central nervous system-active drugs due to the existence of a direct nose-to-brain connection. However, poor solubility limits the amount of drug that can be administered within an aqueous solution. In the present work, the objectives were to develop an ex vivo bioconversion/ permeability evaluation method and to study the ex vivo bioconversion of the hydrophilic phosphate ester prodrug fosphenytoin (FOS) to the active drug phenytoin (PHT) and their comparative nasal permeation. Bioconversion/permeability studies were performed in excised porcine nasal mucosa mounted in Ussing chambers. The physical integrity of the tissues was evaluated by measurement of the transepithelial electrical resistance (TEER). The simultaneous quantitative assay of FOS, PHT and its major metabolite, 5-(4-hydroxyphenyl)- 5-phenylhydantoin (HPPH) was developed and validated according to international guidelines using a liquid chromatography analytical method. The FOS bioconversion rate and PHT and FOS apparent permeability coefficients (Papp) were determined at different time points. FOS bioconversion was also qualitatively investigated in human nasal mucus. The developed liquid chromatography method combines a fast and inexpensive sample preparation with inactivation of the enzymatic metabolism of the prodrug during sample manipulation and storage. It was linear, precise, accurate, and presented a high analyte recovery. FOS was converted ex vivo to PHT but the metabolite HPPHwas not detected. The bioconversion rate increasedwith FOS concentration and with time, which suggests a diffusion-limited process. FOSwas also converted to its active drug by human nasal mucus. A novel mathematical data analysis method was developed to reduce the bias introduced by variable mucosal TEER in the permeability results. At comparable FOS and PHT concentrations the ln(Papp PHT) of both compounds showed little difference,which indicates that the use of a hydrophilic and charged prodrug did not hinder overall drug permeation. At the highest tested FOS concentration it was possible to quantify FOS in the receiver chambers, meaning that at a sufficiently high concentration the FOS permeation rate overcame its bioconversion rate. The ln(Papp PHT) tended to similar equilibrium values as the assay progressed, but with higher FOS concentrations that equilibrium was attained faster. Acidic pH reduced the permeability of both PHT and FOS. The developed bioconversion/permeability evaluation method will constitute an important tool to select the most promising formulations before proceeding to in vivo studies. Importantly, it allowed the demonstration of phosphatase activity and FOS bioconversion in nasal mucosa, aswell as the prodrug's nasal permeation potential. Furthermore, this study demonstrates the possibility of formulating phosphate prodrugs of poorly soluble central nervous system-active drugs as a strategy to increase the solubilized drug doses administered through the nasal route

Associated factors, incidence, and management of gestational and congenital syphilis in a Brazilian state capital: a cross-sectional study

Maternal and child health remains an enduring global challenge, having occupied a prominent position on international agendas since the dawn of the 21st century. During pregnancy, syphilis emerges as the second most prevalent cause of stillbirth on a global scale, potentially leading to a range of adverse outcomes. This study aimed to describe the clinical and epidemiological profile of cases of gestational and congenital syphilis and the hospital care provided for newborns in Campo Grande municipality, Mato Grosso do Sul State, Brazil, from 2013 to 2018. This is a cross-sectional study based on data from Brazilian Notifiable Diseases Surveillance System (SINAN) and hospital medical records. Chi-square or Fisher’s exact test and logistic regression analysis were used to assess the associations and relationships between the child’s clinical outcome at birth and the mother’s clinical-obstetric and epidemiological characteristics. Cumulative detection rate of gestational syphilis was 174.3 cases per 1,000 live births and cumulative incidence of congenital syphilis was 47.7 cases per 1,000 live births. Alcoholism, prenatal care, number of prenatal visits, maternal treatment regimen, and timing of maternal diagnosis were associated with child’s clinical outcome at birth and considered in the regression model. Prenatal visits showed a protective effect against the signs and symptoms of congenital syphilis (odds ratio = 0.37; 95% confidence interval = 0.17−0.77). Medical assistance was considered inadequate in 62.3% of cases. Prenatal consultations should be encouraged among pregnant women. There is a need for better education of health personnel on the treatment and diagnosis of syphilis

Usefulness of the WHOQOL-BREF questionnaire in assessing the quality of life of parents of children with asthma

AbstractObjectiveTo evaluate the quality of life (QOL) of parents of children with asthma and to analyze the internal consistency of the generic QOL tool World Health Organization Quality of Life, abbreviated version (WHOQOL-BREF).MethodsWe evaluated the QOL of parents of asthmatic and healthy children aged between 8 and 16, using the generic WHOQOL-BREF questionnaire. We also evaluated the internal consistency using Cronbach's alpha (αC), in order to determine whether the tool had good validity for the target audience.ResultsThe study included 162 individuals with a mean age of 43.8±13.6 years, of which 104 were female (64.2%) and 128 were married (79.0%). When assessing the QOL, the group of parents of healthy children had higher scores than the group of parents of asthmatic children in the four areas evaluated by the questionnaire (Physical, Psychological Health, Social Relationships and Environment), indicating a better quality of life. Regarding the internal consistency of the WHOQOL-BREF, values of αC were 0.86 points for the group of parents of asthmatic children, and 0.88 for the group of parents of healthy children.ConclusionsParents of children with asthma have impaired quality of life due to their children's disease. Furthermore, the WHOQOL-BREF, even as a generic tool, showed to be practical and efficient to evaluate the quality of life of parents of asthmatic children