Validation and clinical application of a high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the quantitative determination of 10 anti-retrovirals in human peripheral blood mononuclear cells

Development and validation of an ultra-high performance liquid chromatography-tandem mass spectrometry method to quantify antiretroviral drug concentrations in human plasma for therapeutic monitoring

Antiretroviral therapy (ART) is highly effective for the treatment of HIV-1 infection. ART previously consisted of concomitant administration of many drugs, multiple times per day. Currently, ART generally consists of two- or three-drug regimens once daily as fixed-dose combinations. Drug monitoring may be necessary to ensure adequate concentrations are achieved in the plasma over the dosing interval and prevent further HIV resistance formation. Additionally, nonadherence remains an issue, highlighting the need to ensure sufficient ART exposure. Towards this effort, we developed and validated a highly selective ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous quantification of a panel of nine antiretrovirals: abacavir, bictegravir, cabotegravir, dolutegravir, doravirine, emtricitabine, lamivudine, raltegravir, and tenofovir in human plasma. Using only 50 µL of plasma, a simple protein precipitation with acetonitrile with internal standards followed by reconstitution in 50 uL (high) or 400 uL (low) was performed. Analyte separation was achieved using a multistep UPLC gradient mixture of (A: 0.1% formic acid in water and B: acetonitrile) and a Waters CORTECS T3 (2.1 ×100 mm) column. The method was comprehensively validated according to the United States Food and Drug Administration Bioanalytical Guidelines over two clinically relevant ranges (1-250 ng/mL and 100-5000 ng/mL) with excellent linearity (R2 > 0.99 for all). The assay run time was 7.5 min. This method achieves acceptable performance of trueness (89.7-104.1%), repeatability, and precision (CV <15%), and allows for simultaneous quantification of guideline-recommended ART regimens. This method can be utilized for the therapeutic monitoring of antiretrovirals in human plasma.

LC-QQQ-MS based intracellular quantification of bictegravir in peripheral blood mononuclear cells and plasma

Most antiretrovirals (ARVs) have intracellular therapeutic target sites and therefore, their plasma concentration may be misleading when relating to their efficacy or toxicity. A bioanalytical method for quantification of the ARV drug bictegravir (BTG) in its target site peripheral blood mononuclear cells (PBMCs) is not available till date. This is the first time to establish a sufficiently sensitive mass spectrometry-based bioanalytical method to quantify BTG in both rat PBMCs and plasma. The developed method was validated over the range of 1 ng/ml to 100 ng/ml and 0.005 ng-10ng/sample for plasma and PBMCs, respectively. For PBMCs, average accuracy and precision at four quality control levels were found to be 93.30%-110.00% and 6.52%-8.25%, respectively. Plasma and intracellular pharmacokinetics of BTG was evaluated by the developed method in rats and a lack of accumulation of BTG in the PBMCs was observed. Pearson correlation coefficient data analysis indicated a moderated correlation between plasma and PBMC concentration of BTG. Therefore, it will be beneficial to include a quantification plan for BTG in its actual therapeutic target site during all its future research and development work. This reported method can be useful for site-specific monitoring of BTG in research laboratories and pharmaceutical industries.

Tandem mass spectrometry of small-molecule antiviral drugs: 1. HIV-related antivirals

Antiviral drugs are a class of compounds developed specifically for the treatment of viral infections. In the development and subsequent application of antiviral drugs, like for any other class of drugs, quantitative analysis in biological matrix is important, e.g., to establish bioavailability, to study pharmacokinetics, and later on possibly for therapeutic drug monitoring. Liquid chromatography-mass spectrometry (LC-MS) with tandem mass spectrometry (MS-MS) operated in selected-reaction monitoring (SRM) mode is the method of choice in quantitative bioanalysis. As information of the fragmentation of antiviral drugs in MS-MS is very much scattered in the scientific literature, it was decided to collect this information and to review it, not only to understand which product ions are actually used in SRM, but also to assist in other studies, e.g., in the identification of drug metabolites or (forced) degradation products. In this first study, attention is paid to antiviral agents used against HIV infection. The review provides fragmentation schemes of ca. 40 antiviral agents as well as several phosphorylated anabolites. The identity of the product ions used in SRM, i.e., elemental composition and exact-m/z, is tabulated, and more detailed fragmentation schemes are provided.

Chromatographic methods in HIV medicine: Application to therapeutic drug monitoring

HIV antiretroviral therapy spans several different drug classes, meant to combat various aspects of viral infection and replication. Many authors have argued the benefits of therapeutic drug monitoring (TDM) for the HIV patient including compliance assurance and assessment of appropriate drug concentrations; however, the array of drug chemistries and combinations makes TDM an arduous task. HPLC-UV and LC-MS/MS are both frequent instruments for the quantification of HIV drugs in biological matrices with investigators striving to balance sensitivity and affordability. Plasma, the dominant matrix for these analyses, is prepared using protein precipitation, liquid-liquid extraction or solid-phase extraction depending on the specific complement of analytes. Despite the range of polarities found in drug classes relevant to HIV therapeutics, most chromatographic separations utilize a hydrophobic column (C₁₈ ). Additionally, as the clinically relevant samples for these assays are infected with HIV, along with possible co-infections, another important aspect of sample preparation concerns viral inactivation. Although not routine in clinical practice, many published analytical methods from the previous two decades have demonstrated the ability to conduct TDM in HIV patients receiving various medicinal combinations. This review summarizes the analytical methods relevant to TDM of HIV drugs, while highlighting respective challenges.

Interaction between Darunavir and Etravirine Is Partly Mediated by CYP3A5 Polymorphism

OBJECTIVES

To assess the impact of the loss-of-function CYP3A5*3 allele (rs776746, 6986A>G SNP) on darunavir (DRV) plasma concentrations.

METHODS

135 HIV-1 infected patients treated with DRV-based therapy were included in the study and plasma samples were obtained immediately before drug intake in order to determine DRV trough concentrations using an ultra performance liquid chromatography method (UPLC) with diode-array detection (DAD). Noteworthy is the fact that in 16 (11.9%) patients, etravirine (ETR) was combined with DRV. CYP3A5 genotypes were determined using real time PCR method (TaqMan® genotyping assay). The patients were then classified into CYP3A5 expressors (CYP3A5*1 allele carriers) and non-expressors (CYP3A5*3 homozygous). Subsequently, the association between DRV plasma trough concentration ([DRV]plasma) and CYP3A5 genotype-based expression status was analyzed.

RESULTS

45% of the patients were classified as CYP3A5 expressors. In the whole cohort, mean [DRV]plasma was not different between CYP3A5 expressors and non-expressors (1894ng/ml [CI95%: 1566-2290] versus 1737ng/ml [CI95%: 1468-2057], p = 0.43). However, in the subgroup of the 16 patients receiving DRV combined with ETR, a significantly lower [DRV]plasma was observed for CYP3A5 expressors when compared to non-expressors (1385ng/ml [CI95%:886.3-2165] versus 3141ng/ml [CI95%:2042-4831], p = 0.007).

CONCLUSIONS

Interaction between DRV and ETR is partly mediated by CYP3A5 polymorphism with lower DRV plasma trough concentrations in CYP3A5 expressors suggesting a specific ETR-driven CYP3A5 activation only in CYP3A5 expressors. Consequently, these patients might be more at risk of infra-therapeutic [DRV]plasma. This potentially important observation is a good illustration of a genotype-based drug interaction, which could also have considerable consequences if translated to other CYP3A5-metabolized drugs. Further investigations are thus needed to confirm this association and to explore its clinical impact, mainly in the African population among whom CYP3A5 expressors are more frequent, before recommending systematic CYP3A5 pre-emptive genotyping for DRV-ETR co-administration.

Development and validation of a UPLC-MS/MS method for the simultaneous determination of paritaprevir and ritonavir in rat liver

AIM

Determination of paritaprevir and ritonavir in rat liver tissue samples.

RESULTS

We successfully validated a UPLC-MS/MS method to measure paritaprevir and ritonavir in rat liver using deuterated internal standards (d8-paritapervir and d6-ritonavir). The method is linear from 20 to 20,000 and 5 to 10,000 pg on column for paritaprevir and ritonavir, respectively, and is normalized per milligram tissue. Interday and intraday variability ranged from 0.591 to 5.33% and accuracy ranged from -6.68 to 10.1% for quality control samples. The method was then applied to the measurement of paritaprevir and ritonavir in rat liver tissue samples from a pilot study.

CONCLUSION

The validated method is suitable for measurement of paritaprevir and ritonavir within rat liver tissue samples for PK studies.

Quantification of darunavir and etravirine in human peripheral blood mononuclear cells using high performance liquid chromatography tandem mass spectrometry (LC-MS/MS), clinical application in a cohort of 110 HIV-1 infected patients and evidence of a potential drug-drug interaction

OBJECTIVES

To describe the validation of a sensitive high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method allowing the simultaneous quantification of darunavir (DRV) and etravirine (ETR) in peripheral blood mononuclear cells (PBMCs) and its application in a cohort of HIV-1 infected patients.

METHODS

Blood samples were obtained from 110 patients. PMBCs were isolated using density gradient centrifugation. Drug extraction from PBMCs was performed with a 60:40 methanol-water (MeOH-H2O) solution containing deuterated IS (DRV-d9 and ETR-d8). The chromatographic separation was performed on a RP18 XBridge™ column.

RESULTS

The geometric mean (GM) of cell associated concentration ([DRV]CC) and plasmatic concentration ([DRV]plasma) were 360.5ng/mL (CI95%:294.5-441.2) and 1733ng/mL (CI95%:1486-2021), respectively. A geometric mean intracellular (IC)/plasma ratio (GMR) of 0.21 (CI95%:0.18-0.24) was calculated. Adjusted for dose/body surface area and post-intake time, a statistically significant correlation was observed between [DRV]Plasma and the eGFR (p=0.002) and between [DRV]Plasma and the concomitant use of ETR (p=0.038). For the 10 patients receiving ETR in addition to DRV, the GM of [ETR]Plasma (available for 8 out of 10 patients) and [ETR]CC were 492.3ng/mL and 2951ng/mL respectively. The GMR of ETR was 7.6 (CI95%: 3.61-13.83).

CONCLUSIONS

A handy and sensitive high performance LC-MS/MS method allowing the simultaneous quantification of DRV and ETR in PBMCs has been described and successfully applied in the largest cohort of DRV-treated patients reported to date. ETR accumulates more efficiently in PBMCs compared to DRV. We have also highlighted a possible impact of ETR on DRV plasma concentrations requiring further investigations.

Reversed-phase liquid chromatography with electrospray mass detection and 1H and 13C NMR characterization of new process-related impurities, including forced degradants of efavirenz: related substances correlated to the synthetic pathway

In this study, a stability-indicating reversed-phase liquid chromatographic electrospray mass spectrometric method was developed and validated for the determination of process-related impurities and forced degradants of Efavirenz in bulk drugs. Efavirenz was subjected to acid, alkaline hydrolysis, H2O2 oxidation, photolysis, and thermal stress. Significant degradation was observed during alkaline hydrolysis, and the degradants were isolated on a mass-based purification system and characterized by high-resolution mass spectrometry, positive electrospray ionization tandem mass spectrometry, and (1)H and (13)C NMR spectroscopy. Accurate mass measurement and NMR spectroscopy revealed the possible structure of process-related impurities and degradant under stress conditions. The acceptable separation was accomplished on Waters bondapak C18 column (250 mm × 4.6 mm; 5 μm), using 5 mM ammonium acetate and acetonitrile as a mobile phase in a gradient elution mode at a flow rate of 1.0 mL/min. The eluents were monitored by diode array detector at 247 nm and quantitation limits were obtained in the range of 0.1-2.5 μg/mL for Efavirenz, degradants, and process-related impurities. The liquid chromatography method was validated with respect to accuracy, precision, linearity, robustness, and limits of detection and quantification as per International Conference on Harmonization guidelines.

The science of laboratory and project management in regulated bioanalysis

Pharmaceutical drug development is a complex and lengthy process, requiring excellent project and laboratory management skills. Bioanalysis anchors drug safety and efficacy with systemic and site of action exposures. Development of scientific talent and a willingness to innovate or adopt new technology is essential. Taking unnecessary risks, however, should be avoided. Scientists must strategically assess all risks and find means to minimize or negate them. Laboratory Managers must keep abreast of ever-changing technology. Investments in instrumentation and laboratory design are critical catalysts to efficiency and safety. Matrix management requires regular communication between Project Managers and Laboratory Managers. When properly executed, it aligns the best resources at the right times for a successful outcome. Attention to detail is a critical aspect that separates excellent laboratories. Each assay is unique and requires attention in its development, validation and execution. Methods, training and facilities are the foundation of a bioanalytical laboratory.

UPLC-MS/MS quantification of nanoformulated ritonavir, indinavir, atazanavir, and efavirenz in mouse serum and tissues

Animal pharmacokinetic and tissue distribution assays of antiretroviral therapeutic drugs require accurate drug quantification in biological fluids and tissues. Here we report a simple, rapid, and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for quantification of commonly used antiretroviral drugs ritonavir (RTV), indinavir (IDV), atazanavir (ATV), and efavirenz (EFV) in mouse serum and tissues (liver, kidney, lung, and spleen). These antiretroviral drugs are currently the cornerstones of common therapeutic regimens for human immunodeficiency virus (HIV) infection. Chromatographic separation was achieved using a gradient mobile phase (5% acetonitrile in methanol and 7.5mM ammonium acetate (pH 4.0)) on an ACQUITY UPLC(®)BEH Shield RP 18 column. All compounds eluted within a 7 min run time. Lopinavir was used as an internal standard. Detection was achieved by dual positive and negative ionization modes on a quadrupole linear ion trap hybrid mass spectrometer with an electrospray ionization (ESI) source. The dynamic range was 0.2-1000 ng/mL for RTV, IDV, and ATV, and 0.5-1000 for EFV. The method was validated and showed high and consistent intra-day and inter-day accuracy and precision for all analytes. This method is used to support the preclinical development studies of targeted- and sustained-release combination ART (nanoART). The current data demonstrate a 1.5-4 fold increase in serum and tissue AUC of nanoformulated ATV, RTV, and EFV administered to mice when compared to native drug. In addition, the tested formulation enhanced exposure of the same anti-HIV drugs in mouse tissues.

Influence of host genetic factors on efavirenz plasma and intracellular pharmacokinetics in HIV-1-infected patients

BACKGROUND

Efavirenz (EFV) is characterized by interindividual pharmacokinetic variability causing inconsistent clinical responses. Previous studies have identified some possible genetic determinants of the variability in plasma concentrations. However, their impact on EFV intracellular pharmacokinetics remains mostly unexplored.

AIMS

To confirm previous observations concerning the influence of genetic polymorphisms on EFV plasma concentrations and to assess their effect on the intracellular pharmacokinetics of EFV.

MATERIALS & METHODS

EFV concentrations in plasma ([EFV](Cmin)) and in peripheral blood mononuclear cells ([EFV](CC)) were determined in 50 HIV-infected patients. Subjects were genotyped for 13 polymorphisms in 5 different genes (CYP2A6, CYP2B6, CYP3A5, UGT2B7 and ABCB1). Relationships between genetic status and [EFV](Cmin), [EFV](CC) or EFV accumulation in peripheral blood mononuclear cells (EFV accumulation ratio or accumulation ration [AR]) were then evaluated.

RESULTS

CYP2B6 allelic status was associated with differences in [EFV](Cmin) but also in [EFV](CC). Patients carrying at least one mutated allele showed significantly higher [EFV](Cmin) and [EFV](CC) than homozygous wild-type (mutated homozygous [m/m] >heterozygous [wt/m]>homozygous wild-type [wt/wt], p<0.001). ABCB1 rs3842T>C was significantly associated with higher EFV AR (p = 0.032). Finally, the ABCB1 3435C>T SNP was associated with a lower increase in CD4-cell count after EFV therapy initiation.

CONCLUSION

Our study corroborates previous findings indicating that knowledge of CYP2B6 genetic status should be taken into account for an EFV treatment. Our results also constitute the first demonstration of the significant influence of CYP2B6 genetic polymorphisms on [EFV](CC) and suggest that ABCB1 SNPs may also influence the clinical impact of EFV treatment.

The current role of liquid chromatography-tandem mass spectrometry in therapeutic drug monitoring of immunosuppressant and antiretroviral drugs

Therapeutic drug monitoring of critical dose immunosuppressant drugs is established clinical practice and there are similar good reasons to monitor antiretrovirals. The aim of this article is to review the recent literature (last five years), with particular reference to the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS). LC-MS/MS offers many potential advantages. The superior selectivity of LC-MS/MS over immunoassays for immunosuppressant drugs has been widely reported. Simultaneous measurement of a number of drugs can be performed. It is currently routine practice for the four major immunosuppressants (cyclosporin, tacrolimus, sirolimus and everolimus) to be simultaneously measured in whole blood. While up to 17 antiretroviral drugs have been simultaneously measured in plasma. The exquisite sensitivity of LC-MS/MS also provides the opportunity to measure these drugs in alternative matrices, such as dried blood spots, saliva, peripheral blood mononuclear cells and tissue. However, the clinical utility of measuring these classes of drugs in alternative matrices is still to be determined.

Association between ABCC2 polymorphism and lopinavir accumulation in peripheral blood mononuclear cells of HIV-infected patients

Aim: Lopinavir (LPV) is a potent protease inhibitor used in combination with low doses of ritonavir in the treatment of HIV-infected patients. LPV pharmacokinetics is characterized by a large interindividual variability requiring the use of therapeutic drug monitoring in different clinical situations. While the sources of this variability are still unknown, several genetic polymorphisms in biotransformation enzymes or transporter proteins involved in the metabolism and/or the distribution of LPV appear as good candidates. Therefore, the aim of the present study was to investigate the influence of selected genetic polymorphisms on LPV trough plasma concentrations ([LPV]Cmin), LPV concentrations in peripheral blood mononuclear cells ([LPV]CC) and the LPV accumulation ratio ([LPV]CC:[LPV]Cmin). Materials & methods: A total of 53 patients receiving Kaletra® (Abbott Laboratories, IL, USA) (LPV+ritonavir) were genotyped for 14 different polymorphisms in biotransformation enzymes and transporter proteins. [LPV]Cmin, [LPV]CC and [LPV]CC:[LPV]Cmin were compared according to the patient’s genotypes. Results & conclusion: The 4544G>A (rs8187710)polymorphism in ABCC2 was associated with a higher accumulation of LPV in peripheral blood mononuclear cells of HIV-treated patients. As already observed in previous studies, ABCB1 or CYP3A5 polymorphisms had no impact on [LPV]Cmin and we did not detect any influence of these polymorphisms on [LPV]CC and its accumulation in mononuclear cells. In conclusion, this pilot study suggests, for the first time, that the 4544G>A polymorphism in ABCC2 could explain a significant part of the interindividual variability in LPV pharmacokinetics. Further investigations are needed to confirm this association and to explore its real pharmacodynamic impact.