Characterization and in vitro phase I microsomal metabolism of designer benzodiazepines: An update comprising flunitrazolam, norflurazepam, and 4'‐chlorodiazepam (Ro5–4864)

2019 ◽  
Vol 11 (3) ◽  
pp. 541-549 ◽  
Author(s):  
Bjoern Moosmann ◽  
Philippe Bisel ◽  
Folker Westphal ◽  
Maurice Wilde ◽  
Jürgen Kempf ◽  
...  
Keyword(s):  
Phase I ◽  
Microsomal Metabolism ◽  
Designer Benzodiazepines

Role of Phase II Enzymes in the Bioactivation of 1,4-Dichlorobenzene and 1,4-Dibromobenzene

1996 ◽  
Vol 24 (4) ◽  
pp. 603-608
Author(s):  
Moreno Paolini ◽  
Laura Pozzetti ◽  
Renata Mesirca ◽  
Andrea Sapone ◽  
Paola Silingardi ◽  
...  
Keyword(s):  
Dna Binding ◽  
Phase I ◽  
Phase Ii ◽  
Covalent Binding ◽  
Fold Increase ◽  
Test System ◽  
Oxidative Enzymes ◽  
Transferase Activity ◽  
Genetic Toxicology

The use of sodium phenobarbital (PB, CYP2B1 inducer) combined with β-naphthoflavone (β-NF, 1A1) to induce certain Phase I reactions in S9 liver fractions is a standard method for conducting short-term bioassays for genotoxicity. However, because post-oxidative enzymes are also able to activate many precarcinogens, we tested the possibility of adapting S9 liver fractions derived from Phase II-induced rodents to the field of genetic toxicology. In this study, S9 liver fractions derived from Swiss albino CD1 mice fed 7.5g/kg 2-(3)-tert-butyl-4-hydroxyanisole (BHA; a monofunctional Phase II-inducer) for 3 weeks, show a clear pattern of induction with an approximately 3.5–9.5-fold increase in glutathione S-transferase activity. In vitro DNA binding of the promutagenic agents, [14C]-l,4-dichlorobenzene (DCB) and [14C]-1,4-dibromobenzene (DBB), is mediated by such metabolic liver preparations and showed a significant increase in covalent binding capability. In some instances, enzyme activity was more elevated when compared to that obtained with traditional (Phase I-induced) S9. Together with DNA binding, the genetic response of these chemicals in the diploid D7 strain of Saccharomyces cerevisiae used as a biological test system, revealed the ability of the BHA-derived preparations to activate the promutagenic agents, as exemplified by the significant enhancement of mitotic gene-conversion (up to 5.2-fold for DCB and 3.4-fold for DBB) and reverse point mutation (up to 3.6-fold for DCB and 2.5-fold for DBB) at a 4mM concentration. This novel metabolising biosystem, with enhanced Phase II activity, is recommended together with a traditional S9, for detecting unknown promutagens in genotoxicity studies. The routine use of either oxidative or post-oxidative S9 increases the responsiveness of the test and can contribute to the identification of promutagens not detected when using traditional protocols.

376 A phase I/II study of live biotherapeutic MRx0518 in combination with pembrolizumab in patients refractory to immune checkpoint inhibitors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A401-A401
Author(s):  
Shubham Pant ◽  
Amishi Shah ◽  
Pavlos Msaouel ◽  
Matthew Campbell ◽  
Shi-Ming Tu ◽  
...  
Keyword(s):  
Phase I ◽  
Disease Progression ◽  
Immune Checkpoint ◽  
Immune Checkpoint Inhibitors ◽  
Checkpoint Inhibitors ◽  
Tumour Response ◽  
Checkpoint Inhibition ◽  
Single Strain

BackgroundMRx0518 is a novel, human gut microbiome-derived, single-strain, oral live biotherapeutic. It is a bacterium of the Enterococcus genus that was selected for development in the treatment of solid tumours for its strong in vitro and in vivo immunostimulatory activity. In vivo studies have shown that MRx0518 can inhibit tumour growth in different syngeneic cancer models as monotherapy and in combination with checkpoint inhibitors. MRx0518 has been shown to reduce Treg and increase Th1 and Tc1 lymphocyte differentiation in vitro, and increase intratumoral CD4+ and CD8+ T cells and NK cells in vivo.This phase I/II clinical study is evaluating the combination of MRx0518 and pembrolizumab in a cohort of heavily pre-treated patients refractory to immune checkpoint inhibitors (ICIs) to assess whether it is safe and can provide a clinical benefit.MethodsThe study is being conducted in two parts. Part A is complete and evaluated safety of the combination therapy in a cohort of 12 mRCC and mNSCLC patients. This data was assessed by the Safety Review Committee and it was determined appropriate to proceed to Part B. Part B is now recruiting up to 30 additional patients per indication (RCC, NSCLC or bladder cancer) at several US sites. Patients in both parts must be refractory to checkpoint inhibition. This is defined as having had an initial benefit from PD-1 pathway targeting immune checkpoint inhibition (ICI) but developing disease progression confirmed by two radiological scans ≥4 weeks apart in the absence of rapid clinical progression and within 12 weeks of last dose of ICI. Patients are treated with 1 capsule of MRx0518 (1 × 1010 to 1 × 1011 CFU) twice daily and pembrolizumab (200 mg every 3 weeks) for up to 35 cycles or until disease progression. Tumour response is assessed every 9 weeks per RECIST. Blood, stool and urine samples are collected throughout the study to evaluate immune markers and microbiome. Patients may choose to consent to tissue biopsies. The primary objective of the study is to evaluate safety of the combination by monitoring toxicities in the first cycle of treatment. Secondary objectives are to evaluate efficacy via ORR, DOR, DCR (CR, PR or SD ≥6 months) and PFS. Exploratory objectives are to evaluate biomarkers of treatment effect, impact on microbiota and OS and correlation of clinical outcome with PD-L1 CPS/TPS.ResultsN/AConclusionsN/ATrial RegistrationNCT03637803Ethics ApprovalThis study was approved by University of Texas MD Anderson’s Institutional Review Board; approval ref. 2018-0290

Intrathecal Mafosfamide: A Preclinical Pharmacology and Phase I Trial

2005 ◽  
Vol 23 (7) ◽  
pp. 1555-1563 ◽  
Author(s):  
Susan M. Blaney ◽  
Frank M. Balis ◽  
Stacey Berg ◽  
Carola A.S. Arndt ◽  
Richard Heideman ◽  
...  
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Phase I Trial ◽  
Neoplastic Meningitis ◽  
In Vitro Cytotoxicity ◽  
Pharmacokinetic Studies ◽  
Preclinical Studies ◽  
Phase Ii Trials ◽  
Cytotoxicity Studies

Purpose Preclinical studies of mafosfamide, a preactivated cyclophosphamide analog, were performed to define a tolerable and potentially active target concentration for intrathecal (IT) administration. A phase I and pharmacokinetic study of IT mafosfamide was performed to determine a dose for subsequent phase II trials. Patients and Methods In vitro cytotoxicity studies were performed in MCF-7, Molt-4, and rhabdomyosarcoma cell lines. Feasibility and pharmacokinetic studies were performed in nonhuman primates. These preclinical studies were followed by a phase I trial in patients with neoplastic meningitis. There were five dose levels ranging from 1 mg to 6.5 mg. Serial CSF samples were obtained for pharmacokinetic studies in a subset of patients with Ommaya reservoirs. Results The cytotoxic target exposure for mafosfamide was 10 μmol/L. Preclinical studies demonstrated that this concentration could be easily achieved in ventricular CSF after intraventricular dosing. In the phase I clinical trial, headache was the dose-limiting toxicity. Headache was ameliorated at 5 mg by prolonging the infusion rate to 20 minutes, but dose-limiting headache occurred at 6.5 mg dose with prolonged infusion. Ventricular CSF mafosfamide concentrations at 5 mg exceeded target cytotoxic concentrations after an intraventricular dose, but lumbar CSF concentrations 2 hours after the dose were less than 10 μmol/L. Therefore, a strategy to alternate dosing between the intralumbar and intraventricular routes was tested. Seven of 30 registrants who were assessable for response had a partial response, and six had stable disease. Conclusion The recommended phase II dose for IT mafosfamide, administered without concomitant analgesia, is 5 mg over 20 minutes.

In Vitro Metabolism of E2, G2: Novel Bile Acid-Coupling Camptothecin Analogues, in Rat Liver Microsomes

2021 ◽  
Vol 16 ◽  
Author(s):  
Xiangli Zhang ◽  
Qin Shen ◽  
Yi Wang ◽  
Leilei Zhou ◽  
Qi Weng ◽  
...  
Keyword(s):  
Bile Acid ◽  
Phase I ◽  
Rat Liver ◽  
Deoxycholic Acid ◽  
Liver Microsomes ◽  
Intrinsic Clearance ◽  
Rat Liver Microsomes ◽  
Camptothecin Analogues

Background: E2 (Camptothecin - 20 (S) - O- glycine - deoxycholic acid), and G2 (Camptothecin - 20 (S) - O - acetate - deoxycholic acid) are two novel bile acid-derived camptothecin analogues by introducing deoxycholic acid in 20-position of CPT(camptothecin) with greater anticancer activity and lower systematic toxicity in vivo. Objective: We aimed to investigate the metabolism of E2 and G2 by Rat Liver Microsomes (RLM). Methods: Phase Ⅰ and Phase Ⅱ metabolism of E2 and G2 in rat liver microsomes were performed respectively, and the mixed incubation of phase I and phase Ⅱ metabolism of E2 and G2 was also processed. Metabolites were identified by liquid chromatographic/mass spectrometry. Results: The results showed that phase I metabolism was the major biotransformation route for both E2 and G2. The isoenzyme involved in their metabolism had some difference. The intrinsic clearance of G2 was 174.7mL/min. mg protein, more than three times of that of E2 (51.3 mL/min . mg protein), indicating a greater metabolism stability of E2. 10 metabolites of E2 and 14 metabolites of G2 were detected, including phase I metabolites (mainly via hydroxylations and hydrolysis) and their further glucuronidation products. Conclusion: These findings suggested that E2 and G2 have similar biotransformation pathways except some difference in the hydrolysis ability of the ester bond and amino bond from the parent compounds, which may result in the diversity of their metabolism stability and responsible CYPs(Cytochrome P450 proteins).

Effects of Ofloxacin Administration on the Reliability of Urine Glucose Testing

1996 ◽  
Vol 30 (5) ◽  
pp. 469-472
Author(s):  
Tsong-Mei Tsai ◽  
Brian F Shea ◽  
Paul F Souney ◽  
Fred G Volinsky ◽  
Joseph M Scavone ◽  
...  
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Tertiary Care ◽  
Urine Samples ◽  
Care Hospital ◽  
Open Label ◽  
Urine Glucose ◽  
Glucose Testing

OBJECTIVE: TO study the effects of ofloxacin on the reliability of urine glucose testing. DESIGN: Open-label, nonrandomized. SETTING: A university-affiliated tertiary care hospital, ambulatory clinic. PARTICIPANTS: Ten healthy volunteers (8 men and 2 women) aged 22-39 years. MAIN OUTCOME MEASURES: Phase I (in vitro) involved the addition of selected amounts of ofloxacin to a set of standard 50-mL urine samples prepared to simulate glycosuria. Phase II (in vivo) involved the oral administration of ofloxacin 400 mg to 10 subjects. Urine was collected: (1) immediately predose, (2) pooled 0–4 hours postdose, and (3) pooled 4–8 hours postdose. Known glucose concentrations were then added to these samples. Clinitest and Diastix tests were performed on all samples. The accuracy of these tests in determining glucose concentrations was compared among urine samples taken before and after ofloxacin dosing. RESULTS: None of the ofloxacin concentrations in phase I (0,25,50, 100, 200,400, and 800 μg/mL) influenced these testing methods at the urine glucose concentrations of 0.0%, 0.5%, 1%, and 2%. Likewise, the accuracy of these two tests was unaffected by ofloxacin administration in phase II. CONCLUSIONS: In single-dose administration, ofloxacin does not interfere with Clinitest or Diastix for determining urine glucose concentrations. Supported by a grant from the RW Johnson Pharmaceutical Research Institute. Presented in abstract form at the American College of Clinical Pharmacy 1994 Winter Practice and Research Forum, February 6–9, 1994, San Diego. CA.

scholarly journals Serotherapy of B-cell neoplasms with anti-B4-blocked ricin: a phase I trial of daily bolus infusion

Blood ◽  
1992 ◽  
Vol 79 (3) ◽  
pp. 576-585 ◽  
Author(s):  
ML Grossbard ◽  
AS Freedman ◽  
J Ritz ◽  
F Coral ◽  
VS Goldmacher ◽  
...  
Keyword(s):  
Phase I ◽  
B Cell ◽  
Maximum Tolerated Dose ◽  
In Vitro Cytotoxicity ◽  
Bolus Infusion ◽  
Protein Toxin ◽  
Cytotoxicity Studies ◽  
Ricin A

Anti-B4-blocked Ricin (Anti-B4-bR) is an immunotoxin comprised of the anti-B4 monoclonal antibody (MoAb) and the protein toxin “blocked ricin.” The anti-B4 MoAb is directed against the B-lineage-restricted CD19 antigen expressed on more than 95% of normal and neoplastic B cells. Blocked ricin is an altered ricin derivative that has its nonspecific binding eliminated by chemically blocking the galactose binding domains of the B chain. In vitro cytotoxicity studies demonstrate that the IC37 of Anti-B4-bR is 2 x 10(-11) mol/L compared with 4 x 10(-12) mol/L for native ricin. A phase I dose escalation clinical trial was conducted in 25 patients with refractory B-cell malignancies. Anti-B4-bR was administered by daily 1-hour bolus infusion for 5 consecutive days at doses ranging from 1 microgram/kg/d to 60 micrograms/kg/d. Serum levels above 1 nmol/L were achieved transiently in the majority of patients treated at the maximum tolerated dose of 50 micrograms/kg/d for 5 days for a total dose of 250 micrograms/kg. The dose-limiting toxicity was defined by transient, reversible grade 3 elevations in hepatic transaminases, without impaired hepatic synthetic function. Minor toxicities included transient hypoalbuminemia, thrombocytopenia, and fevers. Human antimouse antibody and human anti-ricin antibody were detected in nine patients. One complete response, two partial responses, and eight mixed or transient responses were observed. These results show the in vitro and in vivo cytotoxicity of Anti-B4-bR and indicate that this immunotoxin can be administered as a daily bolus infusion for 5 days with tolerable, reversible toxicity.

scholarly journals A Validated HPLC-PDA-HRMS Method to Investigate the Biological Stability and Metabolism of Antiparasitic Triterpenic Esters

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7154
Author(s):  
Laura Schioppa ◽  
Fanta Fall ◽  
Sergio Ortiz ◽  
Jacques H. Poupaert ◽  
Joelle Quetin-Leclercq
Keyword(s):  
Medicinal Plants ◽  
Degradation Products ◽  
Biological Stability ◽  
Acidic Media ◽  
Microsomal Metabolism ◽  
Plasma Enzymes ◽  
Absorption Studies ◽  
H 30

Pentacyclic triterpenes (PTs) are commonly found in medicinal plants with well-known antiparasitic effects. Previous research on C-3 and C-27 triterpenic esters showed effective and selective in vitro antiparasitic activities and in vivo effectiveness by parenteral routes. The aim of this study was to determine triterpenic esters’ stability in different biological-like media and the main microsomal degradation products. An HPLC-PDA method was developed and validated to simultaneously analyze and quantify bioactive triterpenic esters in methanol (LOQ: 2.5 and 1.25–100 µg/mL) and plasma (LOQ: 5–125 µg/mL). Overall, both triterpenic esters showed a stable profile in aqueous and buffered solutions as well as in entire plasma, suggesting gaining access to the ester function is difficult for plasma enzymes. Conversely, after 1 h, 30% esters degradation in acidic media was observed with potential different hydrolysis mechanisms. C-3 (15 and 150 µM) and C-27 esters (150 µM) showed a relatively low hepatic microsomal metabolism (<23%) after 1 h, which was significantly higher in the lowest concentration of C-27 esters (15 µM) (>40% degradation). Metabolic HPLC-PDA-HRMS studies suggested hydrolysis, hydroxylation, dehydration, O-methylation, hydroxylation and/or the reduction of hydrolyzed derivatives, depending on the concentration and the position of the ester link. Further permeability and absorption studies are required to better define triterpenic esters pharmacokinetic and specific formulations designed to increase their oral bioavailability.

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