3A4 Isoenzyme Research Articles

Paclitaxel Drug-Drug Interactions in the Military Health System.

Paclitaxel is an antineoplastic agent used to treat breast, lung, endometrial, cervical, pancreatic, sarcoma, and thymoma cancer. However, drugs that induce, inhibit, or are substrates of cytochrome P450 (CYP) isoenzymes 2C8 or 3A4 may alter the metabolism of paclitaxel, potentially impacting its effectiveness. The purposes of this study are to provide an overview of paclitaxel use, identify potential drugs that interact with paclitaxel, and describe their clinical manifestations. A retrospective analysis was performed on patients receiving paclitaxel to evaluate types and stages of cancer, treatment regimens, and adverse events of paclitaxel alone or paclitaxel in combination with other antineoplastic drugs, using data retrieved in March 2022 from the US Department of Defense Cancer Registry. Additionally, the study compared the health issues and prescriptions of patients who completed treatment with those who discontinued treatment. It evaluated interactions of paclitaxel with noncancer drugs, particularly antidepressants metabolizing and inhibiting CYP3A4, using data from the Comprehensive Ambulatory/Professional Encounter Record and the Pharmacy Data Transaction Service database. Data were retrieved in October 2022. Of 702 patients prescribed paclitaxel, 338 completed treatment. Paclitaxel discontinuation alone vs concomitantly (P < .001) and 1 drug vs combination (P < .001) both were statistically significant. Patients who took paclitaxel concomitantly with a greater number of prescription drugs had a higher rate of treatment discontinuation than those who received fewer medications. Patients in the completed group received 9 to 56 prescription drugs, and those in the discontinued group were prescribed 6 to 70. Those who discontinued treatment had more diagnosed medical issues than those who completed treatment. The study provides a comprehensive overview of paclitaxel usage from 1996 through 2022 and highlights potential drug interactions that may affect treatment outcomes. While the impact of prescription drugs on paclitaxel discontinuation is uncertain, paclitaxel and antidepressants do not have significant drug-drug interactions.

Effects of microplastics on key reproductive and biochemical endpoints of the freshwater microcrustacean Daphnia magna

Human activities have directly impacted the environment, causing significant ecological imbalances. From the different contaminants resulting from human activities, plastics are of major environmental concern. Due to their high use and consequent discharge, plastics tend to accumulate in aquatic environments. There, plastics can form smaller particles (microplastics, MPs), due to fragmentation and weathering, which are more prone to interact with aquatic organisms and cause deleterious effects, including at the basis of different food webs. This study assessed the effects of two microplastics (polyethylene terephthalate, PET; and polypropylene, PP; both of common domestic use) in the freshwater cladoceran species Daphnia magna. Toxic effects were assessed by measuring reproductive traits (first brood and total number of offspring), and activities of biomarkers involved in xenobiotic metabolism (phase I: cytochrome P-450 isoenzymes CYP1A1, 1A2 and 3A4; phase II/conjugation: glutathione S-transferases; and antioxidant defense (catalase)). Both MPs showed a potential to significantly reduce reproductive parameters in D. magna. Furthermore, PET caused a significant increase in some isoenzymes of CYP450 in acutely exposed organisms, but this effect was not observed in chronically exposed animals. Similarly, the activity of the antioxidant defense (CAT) was significantly increased in acutely exposed animals, but not in chronically exposed organisms. This pattern of effects suggests a possible mechanism of long-term adaptation to the presence of the tested MPs. In conclusion, the herein tested MPs have shown the potential to induce deleterious effects on D. magna mainly observed in terms of the reproductive outcomes. Changes at the biochemical level seems transient and are not likely to occur in long term, environmentally exposed crustaceans.

In silico ADMET, toxicological analysis, molecular docking studies and Molecular dynamics simulation of Afzelin with potential antibacterial effects against Staphylococcus aureus

Afzelin has been designed and tested for its in silico antibacterial activity against DNA gyrase complex of Staphyloccocus aureus. The results of the toxicity study indicate that afzelin displayed moderate antibacterial potential against staphylococcus aureus with LD50 = 5000 mg/Kg, which is almost four times and a half weaker than that obtained for the commercial antibiotic chloramphenicol. The afzelin and the commercial antibiotic chloramphenicol were subjected to docking studies to understand their interaction with DNA gyrase complex of Staphyloccocus aureus. Results indicated a good affinity of afzelin to the chosen target with the formation of four hydrogen bonds and binding energy of 29.82 KJ/mol. ADME study shows that afzelin is not inhibitors of CYP450 IA2, 2C19, 2C9, 2D6, 3A4 isoenzymes which suggests a decrease in their plasma concentrations and a rapid elimination route. Molecular dynamics simulations were performed for 10 ns for afzelin using the gromacs package to assess the conformational stability of protein-ligand complexes during the simulation.

Effects of schisandra lignans on the absorption of protopanaxadiol-type ginsenosides mediated by P-glycoprotein and protopanaxatriol-type ginsenosides mediated by CYP3A4

Ethnopharmacological relevanceGinseng Radix et Rhizoma (GRR) and Schisandrae Chinensis Fructus (SCF) are frequently used as herb pairs in traditional herbal formulas especially for the synergetic beneficial effects on lung and heart. Shengmai-yin (SMY), a noted formula, was first published in the traditional Chinese medicine classic named Yixue Qiyuan written by Zhang Yuansu in the Jin Dynasty, and has been used for deficiency of both qi and yin, palpitation, shortness of breath and spontaneous sweating. In SMY, GRR, a sovereign herb, plays an essential role in tonifying lung and supplementing qi, and SCF as an adjuvant herb contributes to the effects of nourishing yin and promoting fluid production, both of which are traditionally used as invigorants in China, Korea, Japan, and Russia. However, the underlying compatibility mechanism of GRR-SCF has remained unknown. Aim of the studyIn order to explore the impact and underlying mechanism of schisandra chinensis extract (SCE) on the absorption of ginsenosides Rb1, Rc, Rb2 and Rd belonging to protopanaxdiol (PPD)-type and ginsenosides Rg1 and Re belonging to protopanaxtriol (PPT)-type, pharmacokinetic studies, molecular docking technique and single-pass intestinal perfusion (SPIP) experiment were conducted. Material and methodsPreliminarily, pharmacokinetic characteristics of ginseng extract (GE) in the presence and absence of SCE were studied. Thereafter, molecular docking was used to predict whether ginsenosides were P-glycoprotein (P-gp) or cytochrome P450 isoenzyme 3A4 (CYP3A4) substrates. Finally, the effects and underlying mechanism of SCE on the absorption of GE were further investigated by in situ SPIP experiment. ResultsOur findings indicated that SCE could increase exposure in vivo and the intestinal absorption of distinct ginsenosides. Additionally, we found that the PPD-type ginsenosides Rb1, Rc, Rb2, and Rd were substrates for P-gp, and the PPT-type ginsenosides Rg1 and Re were substrates for CYP3A4 rather than P-gp. SCE, which has been found with extensive inhibitory effects on P-gp and CYP3A4, could remarkably promote the intestinal absorption of ginsenosides Rg1, Re, Rb1, Rc, Rb2, and Rd, obtaining similar effects comparable with ketoconazole known as a classic dual inhibitor of P-gp and CYP3A4. ConclusionsThe study demonstrated that SCE could improve the absorption of GE, and revealed the underlying compatibility mechanism of GRR and SCF from the perspective of P-gp and CYP3A4-mediated interactions to some extent, which provided a certain scientific reference for the compatibility and clinical practice of GRR-SCF as common herb pairs in traditional prescriptions such as SMY. Moreover, this study also furnished a strategy for improving the oral bioavailability of different types of ginsenosides by drug combinations.

Pharmacokinetic Drug-Drug Interactions: A Systematic Review of the Cytochrome P450 (CYP) Isoenzyme 3A4

The cytochrome P450 (CYP) isoenzyme 3A4 or CYP3A4 is a major drug-metabolizing enzyme that has the potential to cause pharmacokinetic drug-drug interactions. Primary research studies have demonstrated CYP3A4-mediated drug-drug interactions through a variety of mechanisms. However, there has been no review during the last 10 years of pharmacokinetic drug-drug interactions mediated by CYP3A4 isoenzymes. It is necessary to systematically review the pharmacokinetic drug-drug interactions mediated by CYP3A4. Source review of articles were retrieved from the PubMed and Scopus databases. The preparation of keywords through the population, intervention, comparison, and outcomes (PICO) method written based on the Boolean operator. Reporting the results of the paper search is presented in the Prisma version 1 2020 flowchart. The risk of bias assessment used COHORT tools and Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) tools. Data was analyzed narratively. Pharmacokinetic drug interactions are mediated by CYP3A4 through the mechanism of induction, activation, inhibition, and inactivation. Induction or activation of CYP3A4 can cause an increase in CYP3A4 expression, so that the drug is metabolized more quickly and has the potential to lose drug efficacy. Inhibition and inactivation of CYP3A4 causes plasma drug levels to increase and drug elimination time to last longer. CYP3A4 plays a major role in the bioactivation of drugs that cause hepatotoxicity through the formation of reactive metabolites. The use of drugs needs to be monitored to avoid pharmacokinetic drug interactions.

Drug interactions between ALK inhibitors and warfarin with concurrent use of bucolome: a case report

BackgroundAlectinib, crizotinib, and ceritinib, are anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKIs) that exhibit high protein binding, and their metabolism is associated with the cytochrome P450 (CYP) isoenzymes 2C9 or 3A4. The plasma protein binding rate of warfarin, which is used to prevent and treat venous thromboembolism, is also high. Warfarin is a racemate of S-warfarin and R-warfarin, which are metabolized by CYP2C9 and CYP3A4, respectively. Reports on the drug interactions between each of the above-mentioned ALK-TKIs and warfarin with concurrent use of bucolome are currently lacking.Case presentation.We report a case of a patient receiving warfarin and bucolome, whose international normalized ratio (INR) increased after sequential treatment with alectinib, crizotinib, and ceritinib. The patient was a 61-year-old man with a history of aortic valve regurgitation, who was receiving warfarin treatment following aortic valve replacement. Bucolome, which can enhance the effect of warfarin, was also used simultaneously. The patient was diagnosed with primary lung adenocarcinoma, and ALK rearrangement was detected during second-line chemotherapy. After progression of the disease with chemotherapy, sequential treatment with alectinib, crizotinib, and ceritinib was initiated. Pretreatment INR values were in the therapeutic range (target INR of 2–3) but increased to supratherapeutic levels each time after initiation of alectinib, crizotinib, or ceritinib treatment. Adjustment of warfarin dose or discontinuation of bucolome were necessary to maintain the therapeutic INR range. There were no serious bleeding events or substantial changes in dietary intake.Displacement of plasma protein binding or competitive inhibition of metabolism by alectinib, crizotinib, and ceritinib could increase the plasma concentration of the unbound form of warfarin, resulting in high INR values. In addition, alectinib, crizotinib, and ceritinib might cause displacement of bucolome from plasma proteins, followed by displacement of warfarin or inhibition of warfarin metabolism caused by the unbound form of bucolome.ConclusionsClose monitoring of INR and adjustment of warfarin dosage are needed during treatment with alectinib, crizotinib, or ceritinib in patients who receive warfarin with concurrent use of bucolome.

Impact of Concomitant Use of Azoles on Bortezomib-related Adverse Drug Reactions Using JADER.

Azoles are widely used for prophylaxis in patients with haematologic malignancies and are well known as selective cytochrome P450 isoenzyme 3A4 inhibitors. Although the interaction between bortezomib and azoles has been reported, most previous studies were case reports or small clinical studies. Hence, we conducted a pharmacoepidemiological study to elucidate the impact of azoles on bortezomib-related adverse reactions, using the Japanese adverse drug event report database (JADER). We extracted 19,567 reports on patients prescribed bortezomib and/or azoles. We classified cases into three groups, namely bortezomib, bortezomib and azoles, and azoles groups. We estimated the odds ratios (OR) for the impact of concomitant azole use on five bortezomib-related adverse drug reactions (peripheral neuropathy, thrombocytopenia, neutropenia, leukopenia, and interstitial lung disease) using logistic regression. The OR for peripheral neuropathy in the 'bortezomib and azoles' group was higher than that in the bortezomib group [OR=2.02, 95% confidence interval (CI)=1.32-3.08]. The magnitude of the interaction was stronger with itraconazole than that with fluconazole (itraconazole, OR=3.22, 95% CI=1.78-5.70; fluconazole, OR=1.56, 95% CI=0.86-2.72). We found an association between concomitant administration of azoles with bortezomib and peripheral neuropathy. Azoles may enhance bortezomib-induced peripheral neuropathy based on their pharmacokinetic properties.

PSAT052 Iatrogenic Cushing's Syndrome With a Remote History of Synthetic Glucocorticoid Use in the Setting of a CYP3A4 Inhibitor – Location Matters

Abstract Introduction The most common cause of Cushing's syndrome is iatrogenic due to the exogenous administration of glucocorticoids (GCs). Exogenous GCs disrupt the hypothalamic-pituitary-adrenal (HPA) axis by reducing ACTH production, thereby suppressing cortisol production by the adrenal gland. The degree of HPA axis suppression and recovery varies by the formulation, dose, duration, frequency, timing, and location of GC administration. It is also well known that the clearance of GCs is delayed by inhibitors of cytochrome P450 (CYP) 3A4 isoenzyme. Here we report a case in which a patient on cobicistat developed iatrogenic Cushing's syndrome (ICS) even with a remote history of GC use. Clinical Case A 34-year-old male with Human Immunodeficiency Virus (HIV) on cobicistat and a history of a motor vehicle accident was referred for evaluation of ICS. The patient was started on triamcinolone epidural injections after the accident and developed a ruddy face, weight gain, posterior neck fat redistribution, and purple abdominal striae. He received a total of nine injections over three months at an unknown dose with the last injection being given two years ago. His symptoms improved after stopping the regimen. He received no GCs again until four months prior to presentation when he completed a 4 mg methylprednisolone taper and the cushingoid phenotype returned. Biochemical workup was consistent with HPA axis suppression: morning cortisol &amp;lt;0.5 mcg/dL (4-22 mcg/dL), ACTH &amp;lt;5 pg/mL (6-50 pg/mL), and DHEAS 18 mcg/dL (106-464 mcg/dL). Synthetic glucocorticoid screen was positive for methylprednisolone 5.3 mcg/dL (n &amp;lt;0.10 mcg/dL) and triamcinolone 0.29 mcg/dL (n &amp;lt;0.1 mcg/dL). The patient denied any surreptitious GC use. We concluded the patient still had unmetabolized triamcinolone even after two years due to drug interactions from cobicistat, which is a CYP3A4 inhibitor. Moreover, epidural triamcinolone has the longest half-life, 523 hours, compared to oral or intraarticular injections. Clinical Lesson: GCs are primarily metabolized in the liver by CYP3A4. Very few cases have been reported with the use of cobicistat and the cushingoid phenotype typically appears within 3-6 months of the GC use. However, our patient had detectable triamcinolone and return of ICS two years after epidural injections. It is not enough to know whether a patient received GCs; it is also essential to know how it was given and the location of the injection as the half-lives vary depending on said location. This case reinforces the importance of pharmacovigilance and performing a thorough medication reconciliation, as even a remote history of steroid use in the setting of CYP3A4 inhibitors could lead to ICS. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

Development of a Fast and Highly Sensitive UPLC–MS/MS Technique for Simultaneous Estimation of Artemether and Dihydroartemisinin with its Application to Pharmacokinetic and Biodistribution Studies

Background: Artemether (ART) has been recognized as a potent and rapidly acting antimalarial agent metabolized by cytochrome P450 isoenzyme 3A4 into a more active form dihydroartemisinin (DHA). Hence, it was required to study the pharmacokinetics and biodistribution of ART and DHA for the optimization of dose. Objectives: The current research aims to develop an ultra-performance liquid chromatographytandem mass spectrometry (UPLC-MS/MS) technique with high sensitivity for quantification of ART and DHA simultaneous in the biological fluid. Methods: An isocratic elution mode was applied for delivery of mobile phase (A) ammonium acetate (2mM) in UPLC grade water and (B) acetonitrile (20:80, v/v) comprising 0.1% v/v formic acid in each solvent system with the rate of flow maintained at 400 μL/min. For analyte detection and parent to daughter ion transition tracking, multiple reaction monitoring system was adopted. Artemisinin was selected as the internal standard (IS) for its structural similarity with the analytes. Results: The linearity range of the calibration curve was between 0.5-200 ng/mL. The regression equation indicated r2 = 0.996 for ART and r2 = 0.997 for DHA. Precision and accuracy set in terms of relative error (RE%: ±15) and relative standard deviation (RSD%: ±15) expressed in percentage were within the acceptability range. The % recoveries were within the acceptable limit (90–110%). The detection and quantification limits of the analyte were 0.2 ng/mL and 0.5 ng/mL, respectively. Conclusion: The method demonstrated a useful technique for quantification of ART and DHA for evaluating the pharmacokinetics and biodistribution studies in rat plasma following orally administered nanoformulation.

Impact of Inflammation on Midazolam Metabolism in Severe COVID-19 Patients.

Midazolam is a benzodiazepine frequently used for sedation in patients hospitalized in the intensive care unit (ICU) for coronavirus disease 2019 (COVID‐19). This drug is primarily metabolized by cytochrome P450 3A (CYP3A) isoenzymes. Several studies have suggested that inflammation, frequently observed in these patients, could modulate CYP3A activity. The objective of this work was to study the impact of inflammation on midazolam pharmacokinetics in patients with COVID‐19. Forty‐eight patients hospitalized in the ICU for COVID‐19 and treated with midazolam administered by continuous infusion were included in this study. Midazolam and α‐hydroxymidazolam concentrations were measured and patient data, including the use of CYP3A inhibitors, were collected. Total and unbound concentrations of midazolam and α‐hydroxymidazolam were measured in plasma using a validated liquid‐chromatography coupled with mass spectrometry method. Inflammatory condition was evaluated by C‐reactive protein (CRP) level measurement. Both drug concentrations and CRP measurements were performed on 354 plasma samples. CRP elevation was significantly associated with the α‐hydroxymidazolam/midazolam plasma ratio decrease, whether for the unbound fraction or for the total fraction. Conversely, inflammation was not associated with protein binding modifications. Logically, α‐hydroxymidazolam/midazolam plasma ratio was significantly reduced when patients were treated with CYP3A inhibitors. In this study, we showed that inflammation probably reduces the metabolism of midazolam by CYP3A. These results suggest that molecules with narrow therapeutic margins and metabolized by CYP3A should be administrated with care in case of massive inflammatory situations.

Isolation of Natural Prodrug-Like Metabolite by Simulating Human Prodrug Activation in Filamentous Fungus.

Prodrugs have seen increased clinical applications as therapeutic agents, as they reduce undesirable side effects and improve the therapeutic potential of drugs. While microorganisms produce numerous secondary metabolites with useful medicinal properties, there are only a handful of naturally occurring prodrugs discovered to date. The techniques of isolating secondary metabolites with therapeutic potential from natural product producers have been developed extensively over the years. However, the methods of identifying prodrugs from microbes have not been examined in depth, partly because prodrug-type compounds inherently lack the biological activities that are often used to screen for therapeutically useful secondary metabolites. Therefore, we hypothesized that the difficulty in searching for natural prodrug-type compounds may be addressed by simulating human prodrug activation within natural product-producing microbes. We chose to introduce human CYP (hCYP) into natural product-producing filamentous fungi, because hCYPs are the key enzymes that activate prodrugs in human body, and filamentous fungi are known to be prolific producers of a wide variety of natural products. Here, we successfully identified a cytotoxic, antibiotic and potential anti-diabetic natural product leporin B from Aspergillus flavus that was previously not known to produce this compound. Through bioinformatic and metabolite analyses, we identified the prodrug-equivalent compound leporin C that is converted into leporin B by the action of the hCYP isoenzyme 3A4. By employing various prodrug-activating enzymes and microbes that biosynthesize diverse arrays of natural products, we should be able to probe wider biosynthetic space for identification of interesting prodrug-type natural products.

Evaluation of cardiotoxicity and other adverse effects associated with concomitant administration of artemether/lumefantrine and atazanavir/ritonavir-based antiretroviral regimen in patients living with HIV

The interplay of artemether-lumefantrine (AL) and atazanavir-ritonavir (ATVr) with Cytochrome P (CYP) 3A4 isoenzyme and QTc-interval may spawn clinically significant drug interactions when administered concomitantly. Cardiotoxicity and other adverse effects associated with interaction between AL and ATVr were evaluated in patients with HIV infection and malaria comorbidity. In a two-arm parallel study design, six doses of AL 80/480 mg were administered to 20 participants [control-arm (n = 10) and ATVr-arm (n = 10)], having uncomplicated Falciparum malaria, at intervals of 0, 8, 24, 36, 48 and 60 h respectively. Participants in the control arm took only AL while those in ATVr-arm took both AL and ATVr-based ART regimen. Electrocardiography, adverse events monitoring and blood tests were carried out for each of them at pre and post doses of AL. Data obtained were analyzed. QTc-interval was significantly increased in the ATVr-arm (0.4079 ± 0.008 to 0.4215 ± 0.007 s, p = 0.008) but not in the control-arm (0.4016 ± 0.018 to 0.4024 ± 0.014 s, p = 0.962). All values were, however, within normal range [0.36 – 0.44 / 0.46 s (male/female)]. General body weakness and chest pain were new adverse events reported, at post-dose of AL, in the ATVr-arm but not in the control-arm. There was no significant change (p > 0.05) in the plasma levels of creatinine, alanine aminotransferase, aspartate aminotransferase and hemoglobin at post-dose compared to pre-dose of AL in both arms of study. Concomitant administration of artemether-lumefantrine with atazanavir-ritonavir-based regimen is potentially cardiotoxic but not associated with clinically significant renal, blood nor liver toxicities. They must be used with caution.

Formulation Development and Characterization of Darunavir and Ritonavir Sustained Release Tablets Using Quality by Design Approach

Darunavir is a nonpeptidic inhibitor of protease and is primarily metabolized by cytochrome P450 3A (CYP3A) isoenzymes. It is usually coadministered with low-dose ritonavir (Darunavir/r). Ritonavir is an inhibitor of CYP3A isoenzymes and pharmacologically enhances Darunavir which leads to increased plasma concentrations of darunavir and allows for daily lower dose. Here, we have developed combination SR formulation of Darunavir and Ritonavir and evaluated. In vitro drug release of all formulations was carried out in dissolution medium 900ml of pH 3.0, 0.05 M Sodium Phosphate Buffer + 2% Tween 20 for 75 RPM USP II apparatus (paddle). The results shown that, all the formulations of matrix tablets shown the good release of drug from trialed formulations however all formulations were not releasing the drug in enough amount. In matrix tablets F6, the release of drug shows NLT 80%. So, the formulation F6 have been considered as suitable for the SR tablet of Darunavir and Ritonavir. Tablets were also evaluated though Quality by Design (QbD) method.

Formulation Development and Characterization of Darunavir and Ritonavir Sustained Release Tablets using Quality by Design Approach

Darunavir is a nonpeptidic inhibitor of protease and is primarily metabolized by cytochrome P450 3A (CYP3A) isoenzymes. It is usually coadministered with low-dose ritonavir (Darunavir/r). Ritonavir is an inhibitor of CYP3A isoenzymes and pharmacologically enhances Darunavir which leads to increased plasma concentrations of darunavir and allows for daily lower dose. Here, we have developed combination SR formulation of Darunavir and Ritonavir and evaluated. In vitro drug release of all formulations was carried out in dissolution medium 900ml of pH 3.0, 0.05 M Sodium Phosphate Buffer + 2% Tween 20 for 75 RPM USP II apparatus (paddle). The results shown that, all the formulations of matrix tablets shown the good release of drug from trialed formulations however all formulations were not releasing the drug in enough amount. In matrix tablets F6, the release of drug shows NLT 80%. So, the formulation F6 have been considered as suitable for the SR tablet of Darunavir and Ritonavir. Tablets were also evaluated though Quality by Design (QbD) method.

Severe secondary hyperkalemia and arrhythmia from drug interactions between calcium\u2010channel blocker and voriconazole: a case presentation

BackgroundPatients with kidney disease may have concurrent hypertension and infection. Dihydropyridine calcium-channel blockers (CCB) are the most popular class of antihypertensive drugs used in clinical settings and can be metabolized by cytochrome P450 isoenzyme 3A4 (CYP3A4). Voriconazole is a commonly used antifungal treatment and a CYP3A4-inhibitor. Insufficient attention to drug interactions from the concomitant use of CCB and voriconazole may result in serious adverse reactions.Case presentationHere, we report a patient with acute kidney injury on stable anti-neutrophil cytoplasm antibody associated vasculitis who developed hyperkalemia resulting in sinus arrest with junctional escape rhythm attributed to drug interactions of CCB with voriconazole. This is a very rarely reported case and may be an under-recognized complication. After continuous renal replacement therapy and changing the anti-hypertensive drugs, symptoms, and laboratory abnormalities of the patient fully recovered.ConclusionsThis case warns us of severe consequences of drug interactions. Co-prescription of CYP3A4-inhibitors with calcium-channel blockers increases the risk of hypotension and acute kidney injury, which may further induce hyperkalemia and arrhythmia.

Formulation Development and Characterization of Darunavir and Ritonavir Immediate Release Tablets using Quality by Design approach

Darunavir is a nonpeptidic inhibitor of protease and is primarily metabolized by cytochrome P450 3A (CYP3A) isoenzymes. It is usually Coad ministered with low-dose ritonavir (Darunavir/r). Ritonavir is an inhibitor of CYP3A isoenzymes and pharmacologically enhances Darunavir which leads to increased plasma concentrations of darunavir and allows for daily lower dose. Here, we have developed combination IR formulation of Darunavir and Ritonavir and evaluated. In vitro drug release of all formulations was carried out in dissolution medium 900ml of pH 3.0 0.05 M Sodium Phosphate Buffer + 2% Tween 20 for 75 Min USP II apparatus (paddle). The results shown that, all the formulations of matrix tablets shown the good release of drug from trialed formulations however all formulations were not releasing the drug in enough amount. In matrix tablets F8, the release of drug shows 99%. So, the formulation F8 has been considered as suitable for the immediate release of Darunavir and Ritonavir. Tablets were also evaluated for physic chemical properties, dissolution studies and though Quality by Design (QbD) method.

Commiphora myrrha (Nees) Engl. resin extracts induce phase-I cytochrome P450 2C8, 2C9, 2C19, and 3A4 isoenzyme expressions in human hepatocellular carcinoma (HepG2) cells

Commiphora myrrha (Nees) Engl. (C. myrrha) resin is the most Middle Eastern herbal medicine used against numerous diseases. After being decocted or macerated, this resin is widely consumed among Saudi Arabian patients who are already under prescribed medication. Despite its popularity, no studies have been reported on potential modulation effects of these resin extracts on drug metabolism. Therefore, we studied C. myrrha resin extracts on the expression of cytochrome P450 (CYP) drug-metabolizing isoenzyme in human hepatocellular carcinoma cell line HepG2. The C. myrrha extracts were prepared by sonication and boiling, resembling the most popular traditional preparations of maceration and decoction, respectively. Both boiled and sonicated aqueous extracts were fingerprinted using high-performance liquid chromatography equipped with ultra-violet detector (HPLC-UVD). The viability of HepG2 cells treated with these aqueous extracts was determined using CellTiter-Glo® assay in order to select the efficient and non-toxic resin extract concentrations for phase-I metabolic CYP isoenzyme expression analysis. The isoenzyme gene and protein expression levels of CYP 2C8, 2C9, 2C19, and 3A4 were assessed using reverse transcription-quantitative polymerase chain reaction and Western blot technologies. The HPLC-UVD fingerprinting revealed different chromatograms for C. myrrha boiled and sonicated aqueous extracts. Both aqueous extracts were toxic to HepG2 cells when tested at concentrations exceeding 150 µg/ml of the dry crude extract. The CYP 2C8, 2C9, and 2C19 mRNA expression levels increased up to 4.0-fold in HepG2 cells treated with either boiled or sonicated C. myrrha aqueous extracts tested between 1 and 30 µg/ml, as compared with the untreated cells. However, CYP3A4 mRNA expression level exceeded the 2.0-fold cutoff when the cells were exposed to 30 µg/ml of C. myrrha extracts. The up-regulation of CYP mRNA expression levels induced by both boiled and sonicated C. myrrha aqueous extracts was confirmed at the CYP protein expression levels. In conclusion, both sonicated and boiled C. myrrha aqueous extracts modulate CYP 2C8, 2C9, 2C19, and 3A4 gene expression at clinically-relevant concentrations regardless of preparation methods. Further in vitro and in vivo experiments are required for CYP isoenzyme activity assessment and the establishment of herb-drug interaction profile for these traditional medicinal resin extracts.

CYP450-Mediated metabolism of suvorexant and investigation of metabolites in forensic case specimens

Suvorexant (Belsomra®) is a sedative hypnotic that was approved for use in 2015. It has a novel mechanism of action and was the first dual orexin receptor antagonist (DORA) to be approved for the treatment of sleep disorders. Sedative hypnotics often feature prominently in forensic investigations such as impaired driving and drug-facilitated sexual assault (DFSA) cases. As such, suvorexant is a drug of interest and its identification in forensic toxicology investigations is of significance. However, limited studies have been published to date and the disposition or importance of its metabolites has been largely uninvestigated. In this report, we investigate the enzymes responsible for metabolism and explore the prevalence of metabolites in blood from a series of thirteen forensic investigations. Recombinant cytochrome P450 enzymes (rCYPs) were used to generate phase I metabolites for suvorexant in vitro, and metabolites were identified using liquid chromatography-quadrupole/time-of-flight-mass spectrometry (LC-Q/TOF-MS). Four rCYP isoenzymes (3A4, 2C19, 2D6, and 2C9) were found to contribute to suvorexant metabolism. The only metabolite identified in blood or plasma arose from hydroxylation of the benzyl triazole moiety (M9). This metabolite was identified in seventeen blood and plasma specimens from twelve medicolegal death investigations and one impaired driving investigation. In the absence of a commercially available reference material, the metabolite was confirmed using rCYP-generated in vitro controls using high resolution mass spectrometry.

Interaction of Isatin with Cytochrome P450 Isoenzymes: Investigation by Means of Spectral and Electrochemical Methods The role of Isatin in Cytochromes P450 Ligand-Protein Binding Events

In the present study, the effects of endogenous non-peptide bioregulator isatin (indole-2,3-dione) cytochrome P450 isoenzymes 3A5, 3A4, 2C19, 2E1, and 5A1 were investigated for the first time by means of electrochemical methods. Absorption spectroscopy and electrochemical methods have shown that isatin does not interact with heme as the active center of cytochrome P450 isoenzymes. Isatin has no significant effect on the electrocatalysis of cytochrome P450 3A4 (CYP3A4) in the presence of testosterone chosen as the substrate. Direct electrochemistry of thromboxane synthase (CYP5A1 or TBXAS1) has been investigated using protein film voltammetry. Reversible electrochemical signals of CYP5A1 were observed with midpoint potential of − 0.294 ± 0.012 V (vs Ag/AgCl). The results obtained indicate the existence of the binding sites for isatin on the protein surface of the investigated cytochromes P450, which differ from the active substrate-binding center. For CYP3A4 Arg375, Arg105, and Arg440; for CYP3A5 Arg375 and Arg105; and for CYP2C19 Arg433 were revealed as conserved “hot” amino acid residues involved in the binding of isatin while aligning CYP’s sequences.

RISK MANAGEMENT OF USE DRUGS WITH NARROW THERAPEUTIC INDEX IN CLINICAL PRACTICE. Review

Relevance. Today, the pharmacotherapy of many diseases is significantly expanded. However, the amount of pathological conditions associated with the use of drugs has increased. Drug related problems in some cases can be fatal and increase health care costs. It is necessary to be able to anticipate in advance the possibility of developing such conditions, to prevent them. Therefore, the analysis of the causes and mechanisms of development of these conditions is relevant.&#x0D; Objective. To find out the most common causes of drug related problems and consider the mechanisms of such states.&#x0D; Methods. Analysis of scientific publications in PubMed by keywords for the period 2001-2018.&#x0D; Results. The therapeutic index is the ratio of the dose that causes toxic effects in 50% of patients to the dose that causes the expected therapeutic effect in 50% of patients. The therapeutic index ≤ 3 is an indicator that defines drugs with narrow (small) therapeutic index. These drugs include insulin, digoxin, warfarin, levothyroxine, aminoglycoside antibiotics, carbamazepine, lithium, phenytoin, etc.&#x0D; The risks associated with these drugs are: the use of generic drugs with insufficient bioequivalence, pharmacokinetic interaction and polymorphism of genes of drug metabolism. The main mechanisms of their pharmacokinetic interaction at the stages of absorption (alteration of digestive tract motility, influence on the activity of P-glycoprotein), distribution (competition for blood plasma proteins and tissue proteins), and biotransformation (inhibition or induction of metabolism). The role of polymorphism of genes encoding the activity of isoenzymes cytochrome P450 2C9 and 1A2 and glycoprotein P in the development of adverse drug reactions of drugs with a narrow therapeutic index is presented.&#x0D; Conclusion. Risk management of using drugs with a narrow therapeutic index should include therapeutic drug monitoring of especially generic drugs, assessment of the risks of pharmacokinetic interaction, widespread introduction pharmacogenetic tests for determine the polymorphism of the genes of metabolism enzymes and drug transporters in the clinical practice.