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Highlights: What are the main findings? The validated method was robust, reliable, and sensitive for quantifying ABZ, ABZ-OX, ABZ-ON, and PR simultaneously from the plasma and dried blood spots. The method is well suited for therapeutic drug monitoring due to its high sensitivity, minimal sample volume requirement, and the ability for remote collection. What is the implication of the main finding? Dried blood spot (DBS) analysis represents an alternative sampling technique over conventional blood-sampling methods, particularly for sample collection, enabling a non-clinical setup without requiring special equipment or trained healthcare personnel. Additionally, it minimizes the solvent volume and analysis time and reduces transportation and storage needs. Millions of individuals throughout the world suffer from lymphatic filariasis (LF), which is a morbid disease caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori. These infections belong to tissue-invading nematodes and are one of the major neglected tropical diseases that often result in permanent and enduring disability among individuals in endemic regions. Due to combination therapy, LF eradication has drastically decreased infections globally. The development of blood micro-sampling techniques allowing precise quantitation of drugs in blood would facilitate pharmacokinetic (PK) studies in remote populations. Therefore, an LC-MS/MS bioanalytical method was utilized to analyze albendazole (ABZ), albendazole sulfone (ABZ-ON), albendazole sulfoxide (ABZ-OX), and probenecid (PR) in plasma and dried blood spots. Solid-phase extraction was utilized to extract the analyte from both plasma and blood-spiked DBS. Analytes of interest were eluted with a gradient mobile system using 0.05% formic acid in water (A) and 0.05% formic acid in methanol (B) and separated using a reversed-phase Acquity ®BEH C18 UPLC column (100 × 2.1 mm, 1.7 µm). Precision and accuracy at each QC level were within the acceptable limit, i.e., ±15% for all analytes in both the matrices. Tests for stability under laboratory and storage conditions indicated that no notable changes were observed for plasma and DBS. The LC-MS/MS method demonstrated its capability to consistently identify all target analytes (ABZ, ABZ-ON, ABZ-OX, and PR) at low concentrations, even at the small specimen volumes obtained from DBS cards. This confirms the efficacy and durability of DBS cards as a micro-sampling technique. Moreover, it enhances collection efforts for therapeutic drug monitoring in remote locations for patients infected with lymphatic filariasis. [ABSTRACT FROM AUTHOR]

Hydroxychloroquine (HCQ) is Food and Drug Administration (FDA)‐approved for malaria, systemic and chronic discoid lupus erythematosus, and rheumatoid arthritis. Because HCQ has a proposed multimodal mechanism of action and a well‐established safety profile, it is often investigated as a repurposed therapeutic for a range of indications. There is a large degree of uncertainty in HCQ pharmacokinetic (PK) parameters which complicates dose selection when investigating its use in new disease states. Complications with HCQ dose selection emerged as multiple clinical trials investigated HCQ as a potential therapeutic in the early stages of the COVID‐19 pandemic. In addition to uncertainty in baseline HCQ PK parameters, it was not clear if disease‐related consequences of SARS‐CoV‐2 infection/COVID‐19 would be expected to impact the PK of HCQ and its primary metabolite desethylhydroxychloroquine (DHCQ). To address the question whether SARS‐CoV‐2 infection/COVID‐19 impacted HCQ and DHCQ PK, dried blood spot samples were collected from SARS‐CoV‐2(−)/(+) participants administered HCQ. When a previously published physiologically based pharmacokinetic (PBPK) model was used to fit the data, the variability in exposure of HCQ and DHCQ was not adequately captured and DHCQ concentrations were overestimated. Improvements to the previous PBPK model were made by incorporating the known range of blood to plasma concentration ratios (B/P) for each compound, adjusting HCQ and DHCQ distribution settings, and optimizing DHCQ clearance. The final PBPK model adequately captured the HCQ and DHCQ concentrations observed in SARS‐CoV‐2(−)/(+)participants, and incorporating COVID‐19‐associated changes in cytochrome P450 activity did not further improve model performance for the SARS‐CoV‐2(+) population. [ABSTRACT FROM AUTHOR]

Background: A single co-administered dose of ivermectin (IVM) plus diethylcarbamazine (DEC) plus albendazole (ALB), or triple-drug therapy, was recently found to be more effective for clearing microfilariae (Mf) than standard DEC plus ALB currently used for mass drug administration programs for lymphatic filariasis (LF) outside of sub-Saharan Africa. Triple-drug therapy has not been previously tested in LF-uninfected individuals from Africa. This study evaluated the pharmacokinetics (PK), safety, and efficacy of triple-drug therapy in people with and without Wuchereria bancrofti infection in West Africa. Methods: In this open-label cohort study, treatment-naïve microfilaremic (>50 mf/mL, n = 32) and uninfected (circulating filarial antigen negative, n = 24) adults residing in Agboville district, Côte d’Ivoire, were treated with a single dose of IVM plus DEC plus ALB, and evaluated for adverse events (AEs) until 7 days post treatment. Drug levels were assessed by liquid chromatography and mass spectrometry. Persons responsible for assessing AEs were blinded to participants’ infection status. Findings: There was no difference in AUC0-inf or Cmax between LF-infected and uninfected participants (P>0.05 for all comparisons). All subjects experienced mild AEs; 28% and 25% of infected and uninfected participants experienced grade 2 AEs, respectively. There were no severe or serious adverse events. Only fever (16 of 32 versus 4 of 24, P<0.001) and scrotal pain/swelling in males (6 of 20 versus 0 of 12, P = 0.025) were more frequent in infected than uninfected participants. All LF positive participants were amicrofilaremic at 7 days post-treatment and 27 of 31 (87%) remained amicrofilaremic 12 months after treatment. Conclusions: Moderate to heavy W. bancrofti infection did not affect PK parameters for IVM, DEC or ALB following a single co-administered dose of these drugs compared to uninfected individuals. The drugs were well tolerated. This study confirmed the efficacy of the triple-drug therapy for clearing W. bancrofti Mf and has added important information to support the use of this regimen in LF elimination programs in areas of Africa without co-endemic onchocerciasis or loiasis. Trial registration: ClinicalTrials.gov . [ABSTRACT FROM AUTHOR]

Ultra-performance liquid chromatography (UPLC) interfaced with atmospheric pressure chemical ionization mass-spectrometry was used to separate and quantify ursolic acid (UA) and oleanolic acid (OA) in human plasma. UA and OA were extracted from 0.5 mL human plasma using supported liquid extraction and separated utilizing an Acquity UPLC HSS column. The method has been validated for both UA and OA quantitation with a limit of detection of 0.5 ng/mL. The UPLC separations are carried out with isocratic elution with methanol and 5mM ammonium acetate in water (85:15) as a mobile phase at a flow rate of 0.4 mL/min. The assay was linear from 1 ng/mL to 100 ng/mL for both analytes. The total analysis time was 7 min with the retention times of 3.25 (internal standard), 3.65 (UA) and 3.85 min (OA). Recovery of drug from plasma ranged from 70% to 115%. Analysis of quality control samples at 3, 30 and 80 ng/mL (n = 14) had an intra-day coefficient of variation of 9.9%, 4.3% and 5.5%, respectively. A proof-of-concept study in human patients who consumed apple peels indicates that this analytical method could be applied to clinical studies of UA and/or OA in human subjects. [ABSTRACT FROM AUTHOR]

Combination therapy with anti-filarial drugs is now widely used for treatment of lymphatic filariasis. A rapid, selective, and sensitive liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) method was developed and validated for simultaneous quantitation of diethylcarbamazine (DEC), albendazole (ABZ) and albendazole metabolites in human plasma. Separation and detection of analytes were achieved on a reversed phase column (Acquity UPLC ® BEH C18 column (100 × 2.1 mm, 1.7 μm) with gradient elution using 0.05% formic acid in methanol and 0.05% formic acid as mobile phase. Solid phase extraction was utilized for elution of analytes from the matrix. Thereafter, analytes were monitored by using MS/MS with electrospray ionization source in positive multiple reaction monitoring mode. The MS/MS response was linear over the concentration range from 0.1–200 ng/mL for ABZ and ABZ-ON, 0.5–1000 ng/mL for ABZ-OX and 1–2000 ng/mL for DEC with a correlation coefficient (r 2 ) of 0.998 or better. The within- and between-batch precisions (relative standard deviation, % RSD) and the accuracy (% bias) were within the acceptable limits as per FDA guideline. The validated method was successfully applied to the clinical pharmacokinetic study. Due to high sensitivity and low requirement of sample volume, the method will be applicable for therapeutic drug monitoring of this regimen. [ABSTRACT FROM AUTHOR]

Abstract: A sensitive method has been developed and validated for the determination of artesunate and its active metabolite dihydroartemisinin (DHA) in human plasma using artemisinin as an internal standard. Solid phase extraction (SPE) using Oasis HLB extraction cartridges was used for sample preparation and analysis was performed on a Shimadzu LCMS-2010 in single ion monitoring positive mode using atmospheric pressure chemical ionization (APCI) as an interface. Positive ions were measured using extracted ion chromatogram mode. The extracted ion for artesunate, α- and β-DHA was m/z 221 and for artemisinin was m/z 283. Chromatography was carried out using a Synergi Max-RP, 4μ, 75mm×4.6mm column using glacial acetic acid 0.1%, acetonitrile and methanol mixture (38:46.5:15.5) as a mobile phase delivered at a flow rate of 0.5mL/min. The retention times of artesunate, α- and β-DHA and artemisinin were 17.4, 11.8, 18.7 and 13.4min, respectively, with a total run time of 21min. The assay was linear over the range 1–3000ng/mL for artesunate and DHA. The analysis of quality control samples for artesunate 50, 300, 1300 and 2600ng/mL demonstrated excellent precision with relative standard deviation of 14.3, 11.3, 7.5 and 12.1%, respectively (n=5). Recoveries at concentration of 50, 300, 1300 and 2600ng/mL were 75, 94.5, 74.3 and 75.5%, respectively; similar results were obtained for precision and recovery of DHA. This liquid chromatography–mass spectroscopy (LC–MS) method for the determination of artesunate and DHA in human plasma has superior specification for sensitivity, sample throughput and robustness than previous methods and can reliably quantitate concentrations of both (artesunate and DHA) compounds as low as 1ng/mL. [Copyright &y& Elsevier]

Abstract: An LC-MS method using APCI has been developed and validated for the determination of the anticancer drug vincristine in human plasma, using vinblastine as internal standard. Following solid-phase extraction (SPE) of the sample, the lower limit of quantitation (LLOQ) was 0.18ng/ml, the lower limit of detection was 0.09ng/ml, and the linear calibration range was 0.18–180ng/ml. This method has been used to measure plasma concentrations of vincristine from 0.08 to 24h post bolus in 29 infants as part of a pharmacokinetic study. Concentrations of vincristine at 24h were 0.2–1.36ng/ml. [Copyright &y& Elsevier]

• Optimized sensitive and rapid LC–MS/MS method of phylloquinone and menaquinone-4 quantification in human plasma. • The assay was linear over the concentration range from 0.01 to 50 ng/mL for both analytes. • The validated method was successfully applied to a clinical study in patients with neurodegenerative diseases. A rapid and sensitive liquid chromatographic-tandem mass spectrometric method was developed and validated to simultaneously quantitate vitamin K 1 (PK) and vitamin K 2 (MK-4) concentrations in human plasma to evaluate nutritional interventions. Charcoal-stripped human plasma was used for standard and calibration preparation with vitamin E-d6 as the internal standard. Patient plasma samples were extracted using n-hexane and analytes separated using an ACE –PFP C18 column (50 × 2.1 mm, 3 μ) equipped with standard C 18 guard. The mobile phase consisted of 0.1 % formic acid in water and 0.1 % formic acid in methanol at a flow rate of 0.5 mL/min. Analyte quantification was achieved by using MS/MS with a positive atmospheric pressure chemical ionization in multiple reaction monitoring (MRM) mode. The lower limit of quantification was 0.01 ng/mL for both PK and MK-4. The assay was linear over the concentration range from 0.01–50 ng/mL for all analytes with a determination coefficient (r2) of 0.998 or better. The intra-and inter-day accuracy and precision were within the acceptable limits per FDA guidance. The validated method was successfully applied to a clinical study for quantification of PK and MK-4 in human plasma to assess nutritional status and dietary interventions in patients with neurodegenerative diseases. Baseline plasma concentrations of PK and MK-4 ranged from 0.23 to 1.81 ng/mL and 0.33–0.57 ng/mL, respectively. [ABSTRACT FROM AUTHOR]