Quantification of the Plasma Concentrations of Perampanel Using High-Performance Liquid Chromatography and Effects of the CYP3A4*1G Polymorphism in Japanese Patients

2020 ◽  
Vol 58 (10) ◽  
pp. 915-921
Author(s):  
Sho Ohkubo ◽  
Yumiko Akamine ◽  
Tadashi Ohkubo ◽  
Yuka Kikuchi ◽  
Masatomo Miura

Abstract Here, we developed a novel high-performance liquid chromatography (HPLC) method for quantification of perampanel in clinical practice and investigated the relationships between the plasma concentrations of perampanel obtained by this HPLC method and the CYP3A4*1G polymorphism. The developed HPLC method was validated based on US Food and Drug Administration. The developed HPLC method could be performed with a plasma volume of only 200 μL and had a limit of quantification (LOQ) of 2.5 ng/mL. The coefficients of variation (CVs) for intra- and inter-day assays were less than 10.4 and 7.2%, respectively, and the accuracy was <2.4% for both assays. A total of 12 patients who received 2 mg perampanel had C0 values ranging from 70.5 to 451 ng/mL, and the CV showed a large variation of 51.4%. No correlations were observed between the dose-adjusted C0 and the CYP3A4*1G polymorphism. This method was superior to previously reported methods in terms of plasma volume and LOQ and was clinically applicable. Perampanel showed high variations in individual plasma concentrations; however, individual differences could not be predicted from analysis of the CYP3A4*1G polymorphism before perampanel administration. Therefore, after beginning perampanel treatment, the dose should be determined based on the observed plasma concentration.

2021 ◽  
pp. 1-11
Author(s):  
Sultan M. Alshahrani ◽  
John Mark Christensen

This study was designed to develop and validate a simple and efficient high performance liquid chromatography (HPLC) method to determine flunixin concentrations in Asian elephant’s (Elephas maximus) plasma. Flunixin was administered orally at a dose of 0.8 mg/kg, and blood samples were collected. Flunixin extraction was performed by adding an equal amount of acetonitrile to plasma and centrifuging at 4500 rpm for 25 minutes. The supernatant was removed, and flunixin was analyzed using HPLC-UV detection. Two methods were developed and tested utilizing two different mobile phases either with or without adding methanol (ACN: H2O vs. ACN: H2O: MeOH). Both methods showed excellent linearity and reproducibility. The limit of detection was 0.05 ug/ml and limit of quantification was 0.1 ug/ml. the efficiency of flunixin recovery was maximized by the addition of methanol to mobile phase (ACN: H2O: MeOH as 50:30:20) at 95% in comparison to 23% without methanol. In conclusion, adding methanol to HPLC methods for extraction of flunixin from elephants’ plasma yielded higher recovery rate than without methanol.


Author(s):  
Roger N Johnson ◽  
Russell Sargon ◽  
Gerald Woollard ◽  
James Davidson

Background: Sirolimus is an immunosuppressive agent used after organ transplantation. Monitoring its concentration is clinically relevant, but current methods of measurement using high-performance liquid chromatography (HPLC) are demanding. An immunoassay that uses readily available equipment offers a more convenient alternative. Methods: Blood specimens from transplant patients were assayed for sirolimus by an existing HPLC method with ultraviolet (UV) detection and by the Abbott microparticle enzyme immunoassay (MEIA). Within-run and between-day precision was assessed with duplicate analyses. Accuracy was assessed by comparison of results from the MEIA and HPLC assays, and from recovery experiments. Specificity was tested in specimens from patients taking alternative immunosuppressants. Results: Using specimens with sirolimus concentrations between 3.3 and 39.3 µg/L, within-batch and between-batch coefficients of variation (CVs) were 6.8% and 6.3%, respectively. Using control specimens with mean concentrations of 4.1, 12.1 and 25.4 µg/L, the respective CVs were 8.6%, 3.1% and 3.8 %. Using a Passing-Bablok regression technique, the regression equation was MEIA = 14; 1.26 x HPLC-1.97; the mean bias was 0.96 µg/L. Specimens from patients on cyclosporin and tacrolimus as the sole immunosuppressant had apparent sirolimus concentrations of <1 µg/L. Conclusion: The MEIA assay for sirolimus provides clinically useful information within an accessible format.


Author(s):  
B G Keevil ◽  
W K Wong

A high-performance liquid chromatography (HPLC) method for the determination of sweat chloride was developed and evaluated. This method is capable of measuring chloride ion in sweat eluates with an analytical working range from 0·5 mmol/L to 6 mmol/L (15 to 180 mmol/L in undiluted sweat samples). Precision studies showed that at the levels of 1 mmol/L, 2·5 mmol/L and 3·5 mmol/L, the within batch coefficients of variation were 1·26%, 0·88% and 0·43%, respectively, and the between batch coefficients of variation were 1·31%, 1·75% and 1·07%, respectively. The minimum detection limit was 0·5 mmol/L. This method correlated well with the ion-selective electrode (ISE) method currently in use.


Author(s):  
Yumiko Akamine ◽  
Yuka Sugawara-Kikuchi ◽  
Tsukasa Uno ◽  
Tetsuo Shimizu ◽  
Masatomo Miura

Background This study developed a novel high-performance liquid chromatography (HPLC) method for the simultaneous quantification of clozapine and its active metabolite, N-desmethylclozapine, in human plasma and investigated the effects of various factors, including genetic polymorphisms in cytochrome P450 (CYP) 2D6, CYP3A5, ABCB1 and ABCG2, on the steady-state plasma trough concentrations (C0) of clozapine and N-desmethylclozapine in Japanese patients with schizophrenia. Methods Forty-five patients had been receiving fixed doses of clozapine for at least four weeks. The CYP2D6 ( CYP2D6*2, CYP2D6*5, CYP2D6*10), CYP3A5 ( CYP3A5*3), ABCB1 (1236C > T, 2677G > T/A, 3435C > T) and ABCG2 (421 C > A) genotypes were identified by polymerase chain reaction. Results The within- and between-day coefficients of variation (CV) were less than 11.0%, and accuracy was within 9.0% over the linear range from 10 to 2500 ng/mL for both analytes, and their LOQs were each 10 ng/mL. The median C0/dose (C0/D) ratios of clozapine were significantly higher in patients with the ABCG2 421 A allele than in those with the 421 C/C genotype ( P = 0.010). However, there were no significant differences in C0/D ratios of clozapine and N-desmethylclozapine among ABCB1, CYP2D6 or CYP3A5 genotypes. In multiple regression analysis, including polymorphisms, age, body weight and biochemical data of patients, the ABCG2 polymorphism alone was correlated with the C0/D ratios of clozapine ( R2 = 0.139, P = 0.016). Conclusions Among the various CYPs and drug transporters, BCRP appeared to most strongly influence clozapine exposure. Knowledge of the patient’s ABCG2 421 C > A genotype before initiating therapy may be useful when making dosing decisions aimed at achieving optimal clozapine exposure.


2012 ◽  
Vol 12 (2) ◽  
pp. 201-205 ◽  
Author(s):  
Yuni Retnaningtyas

At present, inulin is often added to multivitamin syrup product. The determination of the component of preparation both qualitatively and quantitatively is important to ensure quality of the product. This research is aimed to develop a high performance liquid chromatography method to analyze inulin in multivitamin syrup preparation. Separation of inulin from the sample, was performed using Aminex column HPX-87H (300 x 7.8 mm) Ion Exclusion at a temperature of 80 °C with isocratic elution system using deionized water as mobile phase at a flow rate of 0.5 mL/min, and detected by using refractive index detector. This method validation showed a good linearity with correlation coefficient (r) of 0.999 while the coefficient of variation of the regression function (Vx0) was 2.00%. The limit of detection (LOD) and the limit of quantification (LOQ) of the method were respectively 0.12 mg/mL and 0.37 mg/mL. The mean absolute recovery of inulin from the simulation sample was 99.42% and the method precision was less than 2%. The proposed method has been applied to the determination of inulin in commercial multivitamin syrup and the recovery of label claim was 99.9 mg/100 mL. The proposed HPLC method is rapid, simple, and selective for routine analysis.


2021 ◽  
Vol 33 (4) ◽  
pp. 930-936
Author(s):  
Khaldun M. Al Azzam ◽  
Ahmad Makahleh ◽  
Bahruddin Saad

A new simple and sensitive high-performance liquid chromatography (HPLC) method for the determination of formaldehyde in flour samples has been developed. Formaldehyde was quantified after derivatization with a readily available reagent, 2,4,6-trichlorophenyl hydrazine (TCPH) under basic conditions. The formaldehyde-TCPH derivative was eluted with chromatographic mobile phase of 70:30 (v/v) acetonitrile:water at a flow rate of 1.0 mL min–1; wavelength, 222 nm; injection volume, 50 μL, using a C18 ODS Hypersil column (250 mm × 4.5 mm, 5 μm). The calibration curve was linear over the range of 0.001-10 μg mL-1 with R2 = 0.999. Recoveries at three different concentration levels (0.1, 1.0 and 5 μg mL-1) ranged from 92.0-101.7% with RSD less than of 2.2%. The limit of detection (LOD) and limit of quantification (LOQ) were 0.3 and 1.0 ng mL-1, respectively. The developed method was used for the determination of formaldehyde in various flour-based samples.


2020 ◽  
Vol 20 (13) ◽  
pp. 1053-1059
Author(s):  
Mahmoud M. Sebaiy ◽  
Noha I. Ziedan

Background: Allergic diseases are considered as the major burden on public health with increased prevalence globally. Histamine H1-receptor antagonists are the foremost commonly used drugs in the treatment of allergic disorders. The target drug in this study, loratadine, belongs to this class of drugs and its biometabolite desloratadine which is also a non-sedating H1 receptor antagonist with anti-histaminic activity being 2.5 to 4 times greater than loratadine. This study aimed to develop and validate a novel isocratic Reversed-phase High-Performance Liquid Chromatography (RP-HPLC) method for rapid and simultaneous separation and determination of loratadine and its metabolite, desloratadine in human plasma. Methods: The drug extraction method from plasma was based on protein precipitation technique. The separation was carried out on a Thermo Scientific BDS Hypersil C18 column (5μm, 250 x 4.60 mm) in a mobile phase of MeOH: 0.025M KH2PO4 adjusted to pH 3.50 using orthophosphoric acid (85: 15, v/v) at an ambient temperature. The flow rate was maintained at 1 mL/min and maximum absorption was measured using the PDA detector at 248 nm. Results: The retention times of loratadine and desloratadine in plasma samples were recorded to be 4.10 and 5.08 minutes, respectively, indicating a short analysis time. Limits of detection were found to be 1.80 and 1.97 ng/mL for loratadine and desloratadine, respectively, showing a high degree of sensitivity of the method. The method was then validated according to FDA guidelines for the determination of the two analytes in human plasma. Conclusion: The results obtained indicate that the proposed method is rapid, sensitive in the nanogram range, accurate, selective, robust and reproducible compared to other reported methods.


1986 ◽  
Vol 49 (5) ◽  
pp. 383-388 ◽  
Author(s):  
PETER SPORNS ◽  
SUET KWAN ◽  
LAWRENCE A. ROTH

Oxytetracycline (OTC), also known commercially as Terramycin, was determined to be more stable in honey than in buffered aqueous solutions at similar pH values and temperatures. A rapid high performance liquid chromatography (HPLC) method was developed to detect and quantitate OTC using a 1:1 dilution (wt/wt) of honey samples in water. Using 355 nm as the wavelength of detection, amounts as low as 0.5 μg/ml could be detected in the above solution. The limits of detection were lowered considerably by a double extraction procedure.


2006 ◽  
Vol 89 (6) ◽  
pp. 1552-1556
Author(s):  
ArmaĞan Önal ◽  
Olcay SaĞiri ◽  
S Müge Çetin ◽  
Sidika Toker

Abstract Reboxetine is used as a selective noradrenaline reuptake inhibitor for the treatment of major depressive disorders. It is effective in the treatment of severe depression and safer to use than traditional tricyclic antidepressants. In this study, a novel, simple, and rapid stability-indicating high-performance liquid chromatography (HPLC) method for reboxetine methansulfonate was successfully developed and validated for the assay of tablets. The method was used to quantify reboxetine in tablets; it employed a C18 column (150 4.6 mm id) with an isocratic mobile phase consisting of methanolphosphate buffer (pH 7, 0.02 M; 55 + 45, v/v) at a flow rate of 1.0 μmL/min. Reboxetine was detected by an ultraviolet detector at 277 nm. The retention time of reboxetine was about 4.5 min. The developed HPLC method was validated with respect to linearity, precision, sensitivity, accuracy, and selectivity. The method was linear over the concentration range 150 g/mL (r 0.9999). The limits of detection and the quantitation of reboxetine were 0.1 and 0.3 μg/mL, respectively. The relative standard deviation values for intraday and interday precision were 0.781.01 and 1.081.37%, respectively. Selectivity was validated by subjecting a stock solution of reboxetine to neutral, acid, and alkali hydrolysis, as well as oxidation, dry heat treatment, and photodegradation. The peaks of the degradation products did not interfere with the peak of reboxetine. The results indicated that the proposed method could be used in a stability assay. The proposed method was successfully applied to the determination of reboxetine in tablets. Excipients present in the tablets did not interfere with the analysis.


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