scholarly journals Determination of the Acyl Glucuronide Metabolite of Mycophenolic Acid in Human Plasma by HPLC and Emit

2000 ◽  
Vol 46 (3) ◽  
pp. 365-372 ◽  
Author(s):  
Maria Shipkova ◽  
Ekkehard Schütz ◽  
Victor William Armstrong ◽  
Paul Dieter Niedmann ◽  
Michael Oellerich ◽  
...  
Keyword(s):  
Mycophenolate Mofetil ◽  
Mycophenolic Acid ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Cross Reactivity ◽  
Kidney Transplant Recipients ◽  
Acyl Glucuronide

Abstract Background: The acyl glucuronide (AcMPAG) of mycophenolic acid (MPA) has been found to possess pharmacologic and potentially proinflammatory activity in vitro. To establish its pharmacologic and toxicologic relevance in vivo, a reversed-phase HPLC method was modified to simultaneously determine MPA, the phenolic MPA-glucuronide (7-O-MPAG), and AcMPAG. In addition, cross-reactivity of AcMPAG in the Emit assay for MPA was investigated. Methods: The procedure used simple sample preparation, separation with a Zorbax Eclipse-XDB-C8 column, and gradient elution. AcMPAG was quantified as 7-O-MPAG-equivalents. Results: The assay was linear up to 50 mg/L for MPA, 250 mg/L for 7-O-MPAG, and 10 mg/L for AcMPAG (r >0.999). Detection limits were 0.01, 0.03, and 0.04 mg/L for MPA, 7-O-MPAG, and AcMPAG, respectively. The recoveries were 99–103% for MPA, 95–103% for 7-O-MPAG, and 104–107% for AcMPAG. The within-day imprecision was <5.0% for MPA (0.2–25 mg/L), <4.4% for 7-O-MPAG (10–250 mg/L), and ≤14% for AcMPAG (0.1–5 mg/L). The between-day imprecision was <6.2%, <4.5%, and ≤14% for MPA, 7-O-MPAG, and AcMPAG, respectively. When isolated from microsomes, purified AcMPAG (1–10 mg/L) revealed a concentration-dependent cross-reactivity in an Emit assay for the determination of MPA ranging from 135% to 185%. This is in accordance with the bias between HPLC and Emit calculated in 270 samples from kidney transplant recipients receiving mycophenolate mofetil therapy, which was greater (median, 151.2%) than the respective AcMPAG concentrations determined by HPLC. AcMPAG was found to undergo hydrolysis when samples were stored up to 24 h at room temperature or up to 30 days at 4 °C or −20 °C. Acidified samples (pH 2.5) were stable up to 30 days at −20 °C. Conclusions: The HPLC and Emit methods for AcMPAG described here may allow investigation of its relevance for the immunosuppression and side effects associated with mycophenolate mofetil therapy.

scholarly journals Simultaneous determination of mycophenolic acid and its glucuronide in human plasma using a simple high-performance liquid chromatography procedure

1998 ◽  
Vol 44 (7) ◽  
pp. 1481-1488 ◽  
Author(s):  
Maria Shipkova ◽  
Paul Dieter Niedmann ◽  
Victor William Armstrong ◽  
Ekkehard Schütz ◽  
Eberhard Wieland ◽  
...  
Keyword(s):  
Mycophenolic Acid ◽  
High Performance ◽  
Internal Standard ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Hplc Method ◽  
Free Concentration ◽  
Elution Chromatography ◽  
Glucuronide Metabolite

Abstract We describe a reversed-phase HPLC method for determination of total mycophenolic acid (MPA), its free concentration (MPAf), and the glucuronide metabolite (MPAG), based on simple sample preparation and gradient elution chromatography. The compounds were quantified in parallel by absorbance at 254 nm and 215 nm in the internal standard mode. Linearity was verified up to 50 mg/L for MPA and up to 500 mg/L for MPAG (r >0.999). Detection limits at 215 and 254 nm were, respectively, 0.01 and 0.03 mg/L for MPA, and 0.03 and 0.1 mg/L for MPAG. The recovery of MPA was 95–106%;recovery of MPAG was 96–106%. The imprecision (CV) for MPA (0.2–25 mg/L) was <8.4% (254 nm) and <4.4% (215 nm) within day (n = 12) and <9.2% (254 nm) and <6.2% (215 nm) between days (n = 12). The imprecision for MPAG (10–250 mg/L) was <4.9% (254 nm) and <3.4% (215 nm) within day, and <6.1% (254 nm) and <5.9% (215 nm) between days. For quantification of MPAf, 100 μL of ultrafiltrate was applied directly to the column. The detection limit was 0.005 mg/L at 215 nm and 0.015 mg/L at 254 nm. In the range between 18–210 μg/L, the within-day CVs were <11.8% (n = 12) and the between-day CVs were <15.8% (n = 12).

scholarly journals Diclofenac and Its Acyl Glucuronide: Determination of In Vivo Exposure in Human Subjects and Characterization as Human Drug Transporter Substrates In Vitro

2015 ◽  
Vol 44 (3) ◽  
pp. 320-328 ◽  
Author(s):  
Y. Zhang ◽  
Y.-H. Han ◽  
S. P. Putluru ◽  
M. K. Matta ◽  
P. Kole ◽  
...  
Keyword(s):  
Human Subjects ◽  
Drug Transporter ◽  
Acyl Glucuronide

scholarly journals DETERMINATION OF 5H-BENZO[2,3][1,4]OXAZEPINO[5,6-B]INDOLES IN RAT PLASMA BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHIC-ULTRAVIOLET METHOD: APPLICATION TO PHARMACOKINETIC STUDIES

2017 ◽  
Vol 10 (12) ◽  
pp. 425 ◽  
Author(s):  
Ashok K Singh ◽  
Vinit Raj ◽  
Amit Rai ◽  
Amit K Keshari ◽  
Pranesh Kumar ◽  
...  
Keyword(s):  
High Performance ◽  
Gradient Elution ◽  
High Performance Liquid Chromatographic ◽  
Rat Plasma ◽  
Reversed Phase ◽  
Pharmacokinetic Studies ◽  
Relative Standard ◽  
Liquid Chromatographic

Objective: Recently, we reported newly synthesized 5H-benzo[2,3][1,4]oxazepino[5,6-b]indole) derivatives and proved their cytotoxicity against hepatocellular carcinoma specific Hep-G2 cell lines. We attempted herein to describe a reversed-phase high-performance liquid chromatographic method for the determination of three most active compounds 6a, 10a, and 15a in rat plasma to predict their pharmacokinetics parameters before in vivo study.Methods: A rapid and sensitive reversed-phase high-performance liquid chromatographic was employed for the determination of 6a, 10a, and 15a in rat plasma. Each compound was separated by a gradient elution of acetonitrile and water with 1 mL/min flow rate. The detector was set at 270, 285, and 275 nm for 6a, 10a, and 15a and the recorded elution times were 2.00, 2.87, and 1.88 min, respectively.Results: The calibration curve was linear with R2 of 0.938, 0.875, and 0.923 over the concentration range of 0.1–50 μg/mL. The inter- and intra-day variations of the assay were lower than 12.26%; the average recovery of 6a, 10a, and 15a was 97.31, 92.56, and 95.23 % with relative standard deviation of 2.12%, 3.25%, and 2.28%, respectively. The Cmax and Tmax were ~ 46.34, 18.56, and 25.65 μg/mL and 2.0, 4.0, and 4.0 h for 6a, 10a, and 15a, respectively, which indicate a robust method of detection in the present experiment.Conclusion: The study suggests that all of the three compounds have a lower rate of absorption, higher volume of distribution, and lower clearance rate, indicating good therapeutic response for in vivo activity. 

The Novel Immunosuppressive Agent Mycophenolate Mofetil Markedly Potentiates the Antiherpesvirus Activities of Acyclovir, Ganciclovir, and Penciclovir In Vitro and In Vivo

1998 ◽  
Vol 42 (2) ◽  
pp. 216-222 ◽  
Author(s):  
Johan Neyts ◽  
Graciela Andrei ◽  
Erik De Clercq
Keyword(s):  
Mycophenolate Mofetil ◽  
Topical Therapy ◽  
Parent Compound ◽  
Immunosuppressive Agent ◽  
Transplant Recipients ◽  
Kidney Transplant Recipients ◽  
Cutaneous Lesions ◽  
Hsv 1

ABSTRACT The immunosuppressive agent mycophenolate mofetil (MMF) has been approved for use in kidney transplant recipients and may thus be used concomitantly for the treatment of intercurrent herpesvirus infections with drugs such as acyclovir (ACV), ganciclovir (GCV), and penciclovir (PCV). We found that MMF and its parent compound mycophenolic acid (at concentrations that are attainable in plasma) strongly potentiate the antiherpesvirus (herpes simplex virus [HSV] type 1 [HSV-1], HSV-2, thymidine kinase-deficient [TK−] HSV-1, both wild-type and TK− varicella-zoster virus, and human cytomegalovirus) activities of ACV, PCV, and GCV (up to 350-fold increases in their activities). The mechanism of potentiation was found to reside in the depletion of endogenous dGTP pools, which favored the inhibitory effect of the triphosphate of ACV, GCV, or PCV on the viral DNA polymerase. The combination of topically applied 5% MMF with 0.1% ACV strongly protected against HSV-1-induced cutaneous lesions in hairless mice, whereas therapy with either compound used singly had no protective effect. Interestingly, the combination of topically applied 5% MMF with 5% ACV was also highly effective in protecting against TK− HSV-2-induced cutaneous lesions (that were refractory to ACV treatment) in athymic nude mice. Topical therapy with MMF was very well tolerated, and no signs of irritation were observed. When given perorally at 200 mg/kg of body weight/day, MMF potentiated to some extent the growth retardation induced by GCV in young NMRI mice. These observations may have clinical implications (i) for those transplant recipients who receive both MMF and either ACV, GCV, or PCV and (ii) for the treatment of ACV-resistant mucocutaneous HSV infections.

A Molecular Approach to Immunoscintigraphy: A Study of the T-Antigen Conformation on the Surface of Tumors

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
T Antigen ◽  
Human Carcinomas ◽  
Animal Tumor ◽  
Synthetic Antigens

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.

Storage of Human Blood Platelets

1974 ◽  
Vol 32 (02/03) ◽  
pp. 405-416 ◽  
Author(s):  
M. R Hardeman ◽  
Carina J L. Heynens
Keyword(s):  
Storage Temperature ◽  
Platelet Rich Plasma ◽  
Blood Platelets ◽  
Storage Period ◽  
Serotonin Uptake ◽  
Hypotonic Shock ◽  
Glycolytic Intermediates

SummaryStorage experiments were performed at 4°, 25° and 37° C with platelet-rich plasma under sterile conditions. In some experiments also the effect of storing platelets at 4° C in whole blood was investigated.Before, during and after three days of storage, the platelets were tested at 37° C for their serotonin uptake and response to hypotonic shock. In addition some glycolytic intermediates were determined.A fair correlation was noticed between the serotonin uptake and hypotonic shock experiments. Both parameters were best maintained at 25° C. Also platelet counting, performed after the storage period, indicated 25° C as the best storage temperature. Determination of glycolytic intermediates did not justify any conclusion regarding the optimal storage temperature. Of the various anticoagulants studied, ACD and heparin gave the best results as to the serotonin uptake and hypotonic shock response, either with fresh or stored platelets. The use of EDTA resulted in the lowest activity, especially after storage.The results of these storage experiments in vitro, correspond well with those in vivo reported in the literature.

Carbon dots derived from Fusobacterium nucleatum for intracellular determination of Fe3+ and bioimaging both in vitro and in vivo

2021 ◽  
Author(s):  
Lijuan Liu ◽  
Shengting Zhang ◽  
Xiaodan Zheng ◽  
Hongmei Li ◽  
Qi Chen ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Fusobacterium Nucleatum ◽  
Living Cells ◽  
First Time ◽  
Fluorescent Carbon Dots ◽  
Fluorescent Carbon

Fusobacterium nucleatum has been employed for the first time to synthesize fluorescent carbon dots which could be applied for the determination of Fe3+ ions in living cells and bioimaging in vitro and in vivo with excellent biocompatibility.

scholarly journals In-vitro and in-vivo metabolism of different aspirin formulations studied by a validated liquid chromatography tandem mass spectrometry method

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michele Dei Cas ◽  
Jessica Rizzo ◽  
Mariangela Scavone ◽  
Eti Femia ◽  
Gian Marco Podda ◽  
...  
Keyword(s):  
Oral Administration ◽  
Whole Blood ◽  
Serum Levels ◽  
Reversed Phase ◽  
Weekly Treatment ◽  
Low Dose Aspirin ◽  
Liquid Chromatography Tandem Mass ◽  
Enteric Coated

AbstractLow-dose aspirin (ASA) is used to prevent cardiovascular events. The most commonly used formulation is enteric-coated ASA (EC-ASA) that may be absorbed more slowly and less efficiently in some patients. To uncover these “non-responders” patients, the availability of proper analytical methods is pivotal in order to study the pharmacodynamics, the pharmacokinetics and the metabolic fate of ASA. We validated a high-throughput, isocratic reversed-phase, negative MRM, LC–MS/MS method useful for measuring circulating ASA and salicylic acid (SA) in blood and plasma. ASA-d4 and SA-d4 were used as internal standards. The method was applied to evaluate: (a) the "in vitro" ASA degradation by esterases in whole blood and plasma, as a function of time and concentration; (b) the "in vivo" kinetics of ASA and SA after 7 days of oral administration of EC-ASA or plain-ASA (100 mg) in healthy volunteers (three men and three women, 37–63 years). Parameters of esterases activity were Vmax 6.5 ± 1.9 and Km 147.5 ± 64.4 in plasma, and Vmax 108.1 ± 20.8 and Km 803.2 ± 170.7 in whole blood. After oral administration of the two formulations, tmax varied between 3 and 6 h for EC-ASA and between 0.5 and 1.0 h for plain-ASA. Higher between-subjects variability was seen after EC-ASA, and one subject had a delayed absorption over eight hours. Plasma AUC was 725.5 (89.8–1222) for EC-ASA, and 823.1(624–1196) ng h/mL (median, 25–75% CI) for plain ASA. After the weekly treatment, serum levels of TxB2 were very low (< 10 ng/mL at 24 h from the drug intake) in all the studied subjects, regardless of the formulation or the tmax. This method proved to be suitable for studies on aspirin responsiveness.

scholarly journals Previous Humoral Immunity to the Endemic Seasonal Alphacoronaviruses NL63 and 229E Is Associated with Worse Clinical Outcome in COVID-19 and Suggests Original Antigenic Sin

Life ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 298
Author(s):  
Daniele Focosi ◽  
Angelo Genoni ◽  
Ersilia Lucenteforte ◽  
Silvia Tillati ◽  
Antonio Tamborini ◽  
...  
Keyword(s):  
Humoral Immunity ◽  
Cross Reactivity ◽  
Clinical Severity ◽  
World Health ◽  
Laboratory Findings ◽  
Cellular And Humoral Immunity ◽  
Rate Ratios ◽  
Original Antigenic Sin

Antibody-dependent enhancement (ADE) of severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) infection has been hypothesized. However, to date, there has been no in vitro or in vivo evidence supporting this. Cross-reactivity exists between SARS CoV-2 and other Coronaviridae for both cellular and humoral immunity. We show here that IgG against nucleocapsid protein of alphacoronavirus NL63 and 229E correlate with the World Health Organization’s (WHO) clinical severity score ≥ 5 (incidence rate ratios was 1.87 and 1.80, respectively, and 1.94 for the combination). These laboratory findings suggest possible ADE of SARS CoV-2 infection by previous alphacoronavirus immunity.

Sign in / Sign up

Export Citation Format

Share Document