Search

A simultaneous ultra-performance liquid chromatography photodiode array detection method was developed and validated for Elvitegravir, Tenofovir and Emtricitabine and Cobicistat drugs in tablet dosage forms. Effective liquid chromatographic quantification was achieved using a Luna C18 (100 × 2.6 mm, 1.6 μ) column with an acetonitrile: 0.1% v/v trifluoro acetic acid (80:20% v/v) mobile phase and a photo diode array detector at 260 nm for a shorter run time of 3 min. The respective retention times for Elvitegravir, Tenofovir, Emtricitabine and Cobicistat were 0.311, 0.792, 1.379 and 2.045 min. The range of linearity was 37.50-225.00, 2.50-15.00, 50.00-300.00 and 37.50-225.00 μg/mL for Elvitegravir, Tenofovir, Emtricitabine and Cobicistat, respectively. A mass spectrometer was employed for quantitative analysis using electron spray ionization multiple reaction monitoring in positive mode. The developed method was validated for different parameters to meet the acceptance criteria as per ICH Q2 (R1) guidelines. Using UPLC-ESI-MS, 12 degradants were identified and their mechanisms were studied., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Tenofovir disoproxil fumarate (TDF) in combination with emtricitabine (FTC) is the backbone for both human immunodeficiency virus (HIV) treatment and pre-exposure prophylaxis (PrEP) worldwide. Tenofovir alafenamide (TAF) with FTC is increasingly used in HIV treatment and was recently approved for PrEP among men-who-have-sex-with-men. TDF and TAF are both metabolized into tenofovir (TFV). Antiretrovirals in plasma are taken up into hair over time, with hair levels providing a long-term measure of adherence. Here, we report a simple, robust, highly sensitive, and validated high-performance liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS)-based analytical method for analyzing TFV and FTC from individuals on either TDF/FTC or TAF/FTC in small hair samples. TFV/FTC are extracted from ~5 mg hair and separated on a column using a gradient elution. The lower quantification limits are 0.00200 (TFV) and 0.0200 (FTC) ng/mg hair; the assay is linear up to 0.400 (TFV) and 4.00 (FTC) ng/mg hair. The intra-day and inter-day coefficients of variance (CVs) are 5.39-12.6% and 6.40-13.5% for TFV and 0.571-2.45% and 2.45-5.16% for FTC. TFV concentrations from participants on TDF/FTC-based regimens with undetectable plasma HIV RNA were 0.0525 ± 0.0295 ng/mg, whereas those from individuals on TAF/FTC-based regimens were 0.0426 ± 0.0246 ng/mg. Despite the dose of TFV in TDF being 10 times that of TAF, hair concentrations of TFV were not significantly different for those on TDF versus TAF regimens. Pharmacological enhancers (ritonavir and cobicistat) did not boost TFV concentrations in hair. In summary, we developed and validated a sensitive analytical method to analyze TFV and FTC in hair and found that hair concentrations of TFV were essentially equivalent among those on TDF and TAF., (© 2021 John Wiley & Sons, Ltd.)

This work describes a simple and sensitive method for the simultaneous isolation, enrichment, identification and quantitation of selected antiretroviral drugs; emtricitabine, tenofovir disoproxil and efavirenz in aqueous samples and plants. The analytical method was based on microwave extraction and hollow fibre liquid phase microextraction technique coupled with ultra-high pressure liquid chromatography-high resolution mass spectrometry. A multivariate approach via a half-fractional factorial design was used focusing on six factors; donor phase pH, acceptor phase HCl concentration, extraction time, stirring rate, supported liquid membrane carrier composition and salt content. The optimal enrichment factors for emtricitabine, tenofovir disoproxil and efavirenz from aqueous phase were 78, 111 and 24, respectively. The analytical method yielded recoveries in the range of 86 to 111%, and quantitation limits for emtricitabine, tenofovir disoproxil and efavirenz in wastewater were 0.033, 0.10 and 0.53 μg L -1 , respectively. The drugs were detected in most samples with concentrations up to 37.6 μg L -1 recorded for efavirenz in wastewater effluent. Roots of the water hyacinth plant had higher concentrations of the investigated drugs ranging from 7.4 to 29.6 μg kg -1 . Overall, hollow fibre liquid phase microextraction proved to be an ideal tool for isolating and pre-concentrating the selected antiretroviral drugs from environmental samples., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A liquid chromatography with triple quadrupole mass spectrometry method was developed and validated for the determination of tenofovir and tenofovir alafenamide concentrations in human plasma and cerebrospinal fluid. Tenofovir and tenofovir alafenamide were extracted from matrix by solid phase extraction. The dried extraction eluents were dissolved in water for LC-MS/MS analysis. Separation was achieved with a Phenomenex Synergi 4 μm Polar-RP 80A column (50 × 2 mm) with a gradient elution of 0.1% formic acid in water and acetonitrile. The total run time was 5 min. Detection of analytes was achieved using electrospray ionization (positive mode) and triple quadrupole selected reaction monitoring. Standard curve concentrations ranged from 0.5 to 500 ng/mL for the plasma assay and 0.1-50 ng/mL for the cerebrospinal fluid assay. The intra- and inter-day accuracy and precision were less than 12% in low, medium, and high quality control samples for both matrices. The validated methods were applied to the analysis of plasma and cerebrospinal fluid samples of a patient undergoing tenofovir therapy which involved the switch from Stribild ® (elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) to Genvoya ® (elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg/tenofovir alafenamide 10 mg)., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Objectives: To present the validation and clinical application of a LC-MS/MS method for the quantification of lamivudine (3TC), emtricitabine (FTC) and tenofovir (TFV) in dried blood spots (DBS) and dried breast milk spots (DBMS)., Methods: DBS and DBMS were prepared from 50 and 30μL of drug-spiked whole blood and human breast milk, respectively. Following extraction with acetonitrile and water, chromatographic separation utilised a Synergi polar column with a gradient mobile phase program consisting of 0.1% formic acid in water and 0.1% formic acid in acetonitrile. Detection and quantification was performed using a TSQ Quantum Ultra triple quadrupole mass spectrometer. The analytical method was used to evaluate NRTI drug levels in HIV-positive nursing mothers-infant pairs., Results: The assay was validated over the concentration range of 16.6-5000ng/mL for 3TC, FTC and TFV in DBS and DBMS except for TFV in DBMS where linearity was established from 4.2-1250ng/mL. Intra and inter-day precision (%CV) ranged from 3.5-8.7 and accuracy was within 15% for all analytes in both matrices. The mean recovery in DBS was >61% and in DBMS >43% for all three analytes. Matrix effect was insignificant. Median AUC 0-8 values in maternal DBS and DBMS, respectively, were 4683 (4165-6057) and 6050 (5217-6417)ngh/mL for 3TC, 3312 (2259-4312) and 4853 (4124-6691)ngh/mL for FTC and 1559 (930-1915) and 56 (45-80)ngh/mL for TFV. 3TC and FTC were quantifiable (>16.6ng/mL) in DBS from 2/6 and 1/6 infants respectively whereas TFV was undetectable in all infants., Conclusions: DBS and DBMS sampling for bioanalysis of 3TC, FTC and TFV is straightforward, robust, accurate and precise, and ideal for use in low-resource settings., (Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.)

Accurate and sensitive liquid-chromatography tandem mass spectrometry method for the quantification of tenofovir and emtricitabine in seminal plasma has been developed and full validated. Molecules were separated by high-performance liquid chromatography on an Atlantis T3 C18 column using a gradient of deionized water and methanol, including 0.05% formic acid (250μl/min) and detected by electrospray ionisation/tandem mass spectrometry in positive ion mode. The method was validated over a clinical range of 3.13-1000ng/mL for tenofovir and 6.25-2000ng/mL for emtricitabine. Inter and intra-assay precisions were <9.37% for tenofovir and<10.88% for emtricitabine, and accuracies were between 0.48% and 8.43% for tenofovir, and between 0.64% and 13.87% for emtricitabine. The developed method was successfully applied for analysing tenofovir and emtricitabine concentrations in seminal plasma samples from a clinical study. The use of tandem mass spectrometry can be a suitable method for the analysis of this kind of matrices, providing high sensitivity and specificity to the analysis., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A new simple, rapid stability indicating assay method has been developed and validated for the determination of emtricitabine, tenofovir disoproxil fumarate, elvitegravir and cobicistat using reverse-phase high-performance liquid chromatography in their pharmaceutical dosage form. The chromatographic separation was performed on an ODS column (250 × 4.6 mm, 5 µm) using mobile phase A (potassium dihydrogen orthophosphate, pH adjusted to 2.5) and mobile phase B (acetonitrile) in the ratio of 55:45% v/v at a flow rate of 1 mL/min. The analytes were detected at 250 nm. The method was found to be linear in the concentration range of 2-12 µg/mL for EMT, 3-18 µg/mL for TNDF, 1.5-9 µg/mL for ELV and COB, with the coefficient value (R(2)) of >0.9990. The accuracy was measured via recovery studies and found to be acceptable, and the percentage recoveries were found in the range of 99.93-100.08 ± 0.5%. Forced degradation studies were also conducted, and the drugs were subjected to various stress conditions such as acid hydrolysis, base hydrolysis, oxidative, photolytic and thermal degradation. The proposed method was successfully validated and applied for the quantitative estimation of these drugs in both bulk and tablet dosage forms., (© The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Self-reported adherence to pre-exposure prophylaxis (PrEP) has limitations, raising interest in pharmacologic monitoring. Drug concentrations in hair and dried blood spots (DBS) are used to assess long-term-exposure; hair shipment/storage occurs at room temperature. The iPrEx Open Label Extension collected DBS routinely, with opt-in hair collection; concentrations were measured with liquid chromatography/tandem mass spectrometry. In 806 hair-DBS pairs, tenofovir (TFV) hair levels and TFV diphosphate (DP) in DBS were strongly correlated (Spearman coefficient r = 0.734; P < .001), as were hair TFV/DBS emtricitabine (FTC) triphosphate (TP) (r = 0.781; P < .001); hair FTC/DBS TFV-DP (r = 0.74; P < .001); hair FTC/DBS FTC-TP (r = 0.587; P < .001). Drug detectability was generally concordant by matrix. Hair TFV/FTC concentrations correlate strongly with DBS levels, which are predictive of PrEP outcomes., (© The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)