Simultaneous determination of intracellular concentrations of tenofovir, emtricitabine, and dolutegravir in human brain microvascular endothelial cells using liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Drug Metabolism and Transport Capacity of Endothelial Cells, Pericytes, and Astrocytes: Implications for CNS Drug Disposition

Therapeutically targeting the brain requires interactions with endothelial cells, pericytes, and astrocytes at the blood brain barrier (BBB). We evaluated regional and cell-type specific drug metabolism and transport mechanisms using rhesus macaques and in vitro treatment of primary human cells. Here, we report heterogenous distribution of representative drugs, tenofovir (TFV), emtricitabine (FTC), and their active metabolites, which cerebrospinal fluid measures could not reflect. We found that all BBB cell types possessed functional drug metabolizing enzymes and transporters that promoted TFV and FTC uptake and pharmacologic activation. Pericytes and astrocytes emerged as pharmacologically dynamic cells that rivaled hepatocytes and were uniquely susceptible to modulation by disease and treatment. Together, our findings demonstrate the importance of considering the BBB as a unique pharmacologic entity, rather than viewing it as an extension of the liver, as each cell type possesses distinct drug metabolism and transport capacities that contribute to differential brain drug disposition.

Cocaine regulates antiretroviral therapy CNS access through pregnane-x receptor-mediated drug transporter and metabolizing enzyme modulation at the blood brain barrier

BACKGROUND

Appropriate interactions between antiretroviral therapies (ART) and drug transporters and metabolizing enzymes at the blood brain barrier (BBB) are critical to ensure adequate dosing of the brain to achieve HIV suppression. These proteins are modulated by demographic and lifestyle factors, including substance use. While understudied, illicit substances share drug transport and metabolism pathways with ART, increasing the potential for adverse drug:drug interactions. This is particularly important when considering the brain as it is relatively undertreated compared to peripheral organs and is vulnerable to substance use-mediated damage.

METHODS

We used an in vitro model of the human BBB to determine the extravasation of three first-line ART drugs, emtricitabine (FTC), tenofovir (TFV), and dolutegravir (DTG), in the presence and absence of cocaine, which served as our illicit substance model. The impact of cocaine on BBB integrity and permeability, drug transporters, metabolizing enzymes, and their master transcriptional regulators were evaluated to determine the mechanisms by which substance use impacted ART central nervous system (CNS) availability.

RESULTS

We determined that cocaine had a selective impact on ART extravasation, where it increased FTC's ability to cross the BBB while decreasing TFV. DTG concentrations that passed the BBB were below quantifiable limits. Interestingly, the potent neuroinflammatory modulator, lipopolysaccharide, had no effect on ART transport, suggesting a specificity for cocaine. Unexpectedly, cocaine did not breach the BBB, as permeability to albumin and 4 kDa FITC-dextran, as well as tight junction proteins and adhesion molecules remained unchanged. Rather, cocaine selectively decreased the pregnane-x receptor (PXR), but not constitutive androstane receptor (CAR). Consequently, drug transporter expression and activity decreased in endothelial cells of the BBB, including p-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance-associated protein 4 (MRP4). Further, cytochrome P450 3A4 (CYP3A4) enzymatic activity increased following cocaine treatment that coincided with decreased expression. Finally, cocaine modulated adenylate kinases that are required to facilitate biotransformation of ART prodrugs to their phosphorylated, pharmacologically active counterparts.

CONCLUSION

Our findings indicate that additional considerations are needed in CNS HIV treatment strategies for people who use cocaine, as it may limit ART efficacy through regulation of drug transport and metabolizing pathways at the BBB.

A green approach for the analysis of emtricitabine bictegravir and tenofovir in a pharmaceutical preparation using novel HPLC and spectrophotometric methods

Two spectrophotometric techniques and a novel HPLC method were consecutively applied for the simultaneous quantification of the active ingredients of emtricitabine (EMC), tenofovir (TNF), and bictegravir (BIC). The first spectrophotometric method is the dual amplitude difference method coupled with the ratio difference method. TNF was determined using the dual amplitude difference method, while BIC and EMC were determined using the ratio difference method. The second spectrophotometric method was the constant multiplication with absorbance extraction method, and was applied for the determination of active substances used in the treatment of human immunodeficiency virus (HIV) infection. BIC was determined by the constant multiplication method, whereas EMC and TNF were determined using the absorbance extraction method. For the HPLC method, the XBridge C18 column was used. The solvent system comprised acetonitrile:phosphate buffer (pH 6.8; 30:70 v/v). All active ingredients were detected at 260.0 nm, and the flow rate was 0.5 mL/min. The experiment was completed within 5.5 min. The experiments carried out enabled the simultaneous analysis of the three active substances and they were economical, fast, environmentally friendly, and simple. The methods have been successfully applied to prepare mixtures and tablets without matrix interference. The methods were evaluated in terms of green chemistry. The methods have been validated according to International Council for Harmonisation (ICH) guidelines.

Cocaine Regulates Antiretroviral Therapy CNS Access Through Pregnane-X Receptor-Mediated Drug Transporter and Metabolizing Enzyme Modulation at the Blood Brain Barrier

Background

Appropriate interactions between antiretroviral therapies (ART) and drug transporters and metabolizing enzymes at the blood brain barrier (BBB) are critical to ensure adequate dosing of the brain to achieve HIV suppression. These proteins are modulated by demographic and lifestyle factors, including substance use. While understudied, illicit substances share drug transport and metabolism pathways with ART, increasing the potential for adverse drug:drug interactions. This is particularly important when considering the brain as it is relatively undertreated compared to peripheral organs and is vulnerable to substance use-mediated damage.

Methods

We used an in vitro model of the human BBB to determine the extravasation of three first-line ART drugs, emtricitabine (FTC), tenofovir (TFV), and dolutegravir (DTG), in the presence and absence of cocaine, which served as our illicit substance model. The impact of cocaine on BBB integrity and permeability, drug transporters, metabolizing enzymes, and their master transcriptional regulators were evaluated to determine the mechanisms by which substance use impacted ART central nervous system (CNS) availability.

Results

We determined that cocaine had a selective impact on ART extravasation, where it increased FTC's ability to cross the BBB while decreasing TFV. DTG concentrations that passed the BBB were below quantifiable limits. Interestingly, the potent neuroinflammatory modulator, lipopolysaccharide, had no effect on ART transport, suggesting a specificity for cocaine. Unexpectedly, cocaine did not breach the BBB, as permeability to albumin and tight junction proteins and adhesion molecules remained unchanged. Rather, cocaine selectively decreased the pregnane-x receptor (PXR), but not constitutive androstane receptor (CAR). Consequently, drug transporter expression and activity decreased in endothelial cells of the BBB, including p-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance-associated protein 4 (MRP4). Further, cytochrome P450 3A4 (CYP3A4) enzymatic activity increased following cocaine treatment that coincided with decreased expression. Finally, cocaine modulated adenylate kinases are required to facilitate biotransformation of ART prodrugs to their phosphorylated, pharmacologically active counterparts.

Conclusion

Our findings indicate that additional considerations are needed in CNS HIV treatment strategies for people who use cocaine, as it may limit ART efficacy through regulation of drug transport and metabolizing pathways at the BBB.

Comprehensive Review on Different Analytical Techniques for HIV 1- Integrase Inhibitors: Raltegravir, Dolutegravir, Elvitegravir and Bictegravir

The advent of HIV-Integrase inhibitors (IN) has marked a significant impact on the lives of HIV patients. Since the launch of the first anti retro-viral drug "Azidothymidine" to the recent advances of IN inhibitors, about 27.4 million people benefit by antiretroviral therapy (ART). The path had been challenging due to many crossroads, leading to the discovery of newer targets. One such recent ART target is Integrase. Use of Integrase inhibitors has surpassed the usage of all other ART owing to a strong barrier to resistance and have been reported to be the first-line therapy. Raltegravir, Elvitegravir, Dolutegravir and Bictegravir are US FDA approved IN inhibitors. The high usage of ART created an opportunity to study various analytical techniques for IN inhibitors. Hitherto, no review encompassing all IN inhibitors is presented. Herein, this review describes the analytical techniques employed for IN inhibitors estimation and quantification reported in the literature and official compendia. Literature suggests that most studies focus on LC-MS/MS and HPLC methods for drug estimation, and few reports suggest spectrophotometric, spectrofluorimetric and electrochemical methods. Furthermore, the review presents the techniques that describe the quantification of integrase drugs in various matrices. Although, antiretroviral drugs are extensively used but data suggests that limited studies have been conducted for determination of impurity profile and stability. This therefore, presents a scope to detect and validate impurities in order to meet ICH guidelines for their limits and further to improve the quality and safety of antiretroviral drugs.

Determination of intracellular anlotinib, osimertinib, afatinib and gefitinib accumulations in human brain microvascular endothelial cells by liquid chromatography/tandem mass spectrometry

RATIONALE

Brain metastases are a common complication in patients with non-small-cell lung cancer (NSCLC). Anlotinib hydrochloride is a novel multi-target tyrosine kinase inhibitor (TKI) exhibiting a superior overall response rate for brain metastases from NSCLC. The penetrability of anlotinib and three generations of epidermal growth factor receptor (EGFR) TKIs (osimertinib, afatinib and gefitinib) into brain microvascular endothelial cells (HBMECs) was compared.

METHODS

A sensitive quantification method for the four TKIs was developed using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). Anlotinib and the three EGFR TKIs were separated on an ACQUITY BEH C18 column after a direct protein precipitation, and then analyzed using electrospray ionization in positive ion mode. The linearity, accuracy, precision, limit of quantification, specificity and stability were assessed.

RESULTS

The four analytes could be efficiently quantified in a single run of 3.8 min. The validation parameters of all analytes satisfy the acceptance criteria of bioanalytical method guidelines. The calibration range was 0.2-200 ng mL^-1 for anlotinib and gefitinib, 1-500 ng mL^-1 for osimertinib and 1-200 ng mL^-1 for afatinib. The penetration of anlotinib across HBMECs was comparable with that of afatinib and gefitinib but less than that of osimertinib.

CONCLUSIONS

A sensitive LC/MS/MS method to simultaneously measure anlotinib, osimertinib, afatinib and gefitinib in cell extracts was successfully validated and applied to determine their uptake inside HBMECs, which could pave the way for future research on the role of anlotinib in NSCLC brain metastases.

Validation of a UHPLC-MS/MS Method to Quantify Twelve Antiretroviral Drugs within Peripheral Blood Mononuclear Cells from People Living with HIV

Recently, anti-HIV treatment has achieved high efficacy and tolerability. Nevertheless, few data are available about the intracellular penetration of antiretrovirals, partly due to the technical challenges related to intracellular quantification. This work aimed to validate an ultra-high performance liquid chromatography (UHPLC) tandem mass spectrometry (MS/MS) method for the simultaneous quantification of maraviroc, nevirapine, rilpivirine, dolutegravir, raltegravir, cobicistat, darunavir, ritonavir, atazanavir, efavirenz, elvitegravir, and etravirine within peripheral blood mononuclear cells (PBMCs) and apply it to samples from patients. PBMCs were isolated by density gradient on cell preparation tubes (CPT). Samples were prepared by addition of internal standards (IS), sonication, centrifugation, and drying. Reconstituted extracts underwent chromatographic separation by reversed phase UHPLC and detection was performed by electrospray ionization and multiple reaction monitoring. Method validation followed FDA and EMA guidelines, showing acceptable accuracy, precision, recovery and IS-normalized matrix effect. The application to 56 samples from patients undergoing antiretroviral treatment provided description of intracellular penetration, showing method eligibility for future studies.

Rapid quantification of tenofovir in umbilical cord plasma and amniotic fluid in hepatitis B mono-infected pregnant women during labor by ultra-performance liquid chromatography/tandem mass spectrometry

RATIONALE

Tenofovir (TFV) is a first-line antiviral agent against hepatitis B virus (HBV) and is recommended for the prevention of mother-to-infant transmission of HBV. To study the distribution of TFV in umbilical cord plasma and amniotic fluid of HBV-infected pregnant women, a rapid and sensitive method for TFV determination was developed and validated.

METHODS

The quantification method was developed using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). The analytes were separated on an Acquity UPLC HSS T3 column under gradient elution with methanol and 0.01% ammonia solution in 10 mM ammonium acetate/water. This is the first reported method for the determination of TFV using alkaline rather than acidic mobile phases. Linearity, accuracy, precision, limit of quantification, specificity and stability were assessed.

RESULTS

Detection of TFV was achieved within 4 min. The calibration curves for TFV quantification showed excellent linearity in the range of 1-500 ng/mL. The intra- and interbatch precision and accuracy ranged from -4.35% to 6.92%. This method was successfully applied to determination of samples from 50 HBV mono-infected women undergoing tenofovir disoproxil fumarate therapy. The mean concentrations of TFV in the umbilical cord and amniotic fluid samples were 29.2 (4.6-86) and 470.9 (156-902) ng/mL, respectively, which showed a moderate positive correlation (r = 0.5299, P<0.001).

CONCLUSIONS

A simple, rapid but sensitive bioanalytical method to determine TFV concentration in both umbilical cord plasma and amniotic fluid using LC/MS/MS was developed and applied to HBV-infected women during labor who were undergoing TDF therapy, which will help us understand the efficacy and safety of tenofovir during pregnancy.

Antiretroviral concentration measurements as an additional tool to manage virologic failure in resource limited settings: a case control study

Background

Several studies demonstrate a correlation between sub-therapeutic concentrations of antiretroviral drugs and virologic failure. We examined the sensitivity, specificity and predictive values of sub-therapeutic drug levels in predicting viralogic failure.

Methods

This was a case control study with cases being samples of participants with virologic failure, and controls samples of participants with virologic suppression. We analyzed samples obtained from participants that had been on antiretroviral treatment (ART) for at least 6 months. Virologic failure was defined as HIV-RNA viral load ≥ 1000 copies/ml. Sub-therapeutic drug levels were defined according to published reference cutoffs. The diagnostic validity of drug levels for virologic failure was assessed using plasma viral loads as a gold standard.

Results

Sub-therapeutic ART concentrations explained only 38.2% of virologic failure with a probability of experiencing virologic failure of 0.66 in a patient with low drug levels versus 0.25 for participants with measurements within or above the normal range. Approximately 90% of participants with ART concentrations above the lower clinical cut off did not have virologic failure.

Conclusions

These results support prior indication for therapeutic drug monitoring in cases of suspected virologic failure.

Cell-type specific differences in antiretroviral penetration and the effects of HIV-1 Tat and morphine among primary human brain endothelial cells, astrocytes, pericytes, and microglia

The inability to achieve adequate intracellular antiretroviral concentrations may contribute to HIV persistence within the brain and to neurocognitive deficits in opioid abusers. To investigate, intracellular antiretroviral concentrations were measured in primary human astrocytes, microglia, pericytes, and brain microvascular endothelial cells (BMECs), and in an immortalized brain endothelial cell line (hCMEC/D3). HIV-1 Tat and morphine effects on intracellular antiretroviral concentrations also were evaluated. After pretreatment for 24 h with vehicle, HIV-1 Tat, morphine, or combined Tat and morphine, cells were incubated for 1 h with equal concentrations of a mixture of tenofovir, emtricitabine, and dolutegravir at one of two concentrations (5 μM or 10 μM). Intracellular drug accumulation was measured using LC-MS/MS. Drug penetration differed depending on the drug, the extracellular concentration used for dosing, and cell type. Significant findings included: 1) Dolutegravir (at 5 μM or 10 μM) accumulated more in HBMECs than other cell types. 2) At 5 μM, intracellular emtricitabine levels were higher in microglia than other cell types; while at 10 μM, emtricitabine accumulation was greatest in HBMECs. 3) Tenofovir (5 or 10 μM extracellular dosing) displayed greater accumulation inside HBMECs than in other cell types. 4) After Tat and/or morphine pretreatment, the relative accumulation of antiretroviral drugs was greater in morphine-exposed HBMECs compared to other treatments. The opposite effect was observed in astrocytes in which morphine exposure decreased drug accumulation. In summary, the intracellular accumulation of antiretroviral drugs differed depending on the particular drug involved, the concentration of the applied antiretroviral drug, and the cell type targeted. Moreover, morphine, and to a lesser extent Tat, exposure also had differential effects on antiretroviral accumulation. These data highlight the complexity of optimizing brain-targeted HIV therapeutics, especially in the setting of chronic opioid use or misuse.