Population pharmacokinetic modeling of dolutegravir/lamivudine to support a once-daily fixed-dose combination regimen in virologically suppressed adults living with HIV-1.

A fixed-dose combination (FDC) of 50 mg dolutegravir and 300 mg lamivudine is indicated for the treatment of HIV-1 infection. This analysis aimed to characterize the population pharmacokinetics (PK) of dolutegravir and lamivudine based on data from a phase 3 study (TANGO) in virologically suppressed adults living with HIV-1 switching to dolutegravir/lamivudine FDC. These analyses included 362 participants who contributed 2,629 dolutegravir and 2,611 lamivudine samples collected over 48 weeks. A one-compartment model with first-order absorption and elimination parameterized by apparent oral clearance (CL/F), apparent volume of distribution (V/F), and absorption rate constant (Ka) described dolutegravir PK. Covariate search yielded body weight, bilirubin, and ethnicity as predictors of CL/F, and weight was predictive for V/F. The estimates of CL/F, V/F, and Ka were 0.858 L/h, 16.7 L, and 2.15 h-1, respectively. A two-compartment model with first-order absorption and elimination parameterized by CL/F, apparent intercompartmental clearance (Q/F), apparent central volume of distribution (V2/F), apparent peripheral volume of distribution (V3/F), and Ka described lamivudine PK. Covariate search yielded eGFR and race as predictors of CL/F, and weight was predictive for V2/F. The estimated parameter values were CL/F = 19.6 L/h, Q/F = 2.97 L/h, V2/F = V3/F = 105 L, and Ka = 2.30 h-1. The steady-state prediction suggested that the effect of covariates dolutegravir and lamivudine exposures was small (<20%) and not clinically relevant. Therefore, no dose adjustments are recommended based on these analyses. The results support the use of dolutegravir/lamivudine FDC in the treatment of HIV-1 infection in adults.CLINICAL TRIALSThis study is registered with ClinicalTrials.gov as NCT03446573.

Quantitative determination of armodafinil in human plasma by liquid chromatography-electrospray mass spectrometry: Application to a clinical study.

Armodafinil is a wake-promoting agent approved in 2007 by the US Food and Drug Administration for the treatment of excessive sleepiness. A rapid, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of armodafinil in human plasma was developed and validated. Armodafinil and internal standard (armodafinil d-10) were extracted from human plasma using protein precipitation combined with liquid-liquid extraction. This developed method only requires 50 µL of plasma for the analysis. The chromatographic separation was performed with a Waters symmetry, C18 , 4.6 × 150 mm, 5 µm column using formic acid, water and acetonitrile as solvent delivered at a 0.7 mL/min flow rate. The total run time of the method was 3 min. The method was validated according to regulatory guidance in terms of specificity, selectivity, linearity, matrix effect, recovery and stability. Optimized Q1/Q3 mass transitions for armodafinil and armodafinil d-10 were 274.1/167.2 (m/z) and 284.4/177.4 (m/z) respectively. The method showed linearity within the tested concentration range of 10-10,000 ng/mL. The method was successfully applied to quantify armodafinil concentrations after single oral administration of a 250 mg tablet in a clinical study conducted in healthy volunteers. Significant advantages of this method are minimal sample volume, short run time and a lower LLOQ.

Simultaneous quantitation of acetylsalicylic acid and clopidogrel along with their metabolites in human plasma using liquid chromatography tandem mass spectrometry.

The interest in therapeutic drug monitoring has increased over the last few years. Inter- and intra-patient variability in pharmacokinetics, plasma concentration related toxicity and success of therapy have stressed the need of frequent therapeutic drug monitoring of the drugs. A sensitive, selective and rapid liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous quantification of acetylsalicylic acid (aspirin), salicylic acid, clopidogrel and carboxylic acid metabolite of clopidogrel in human plasma. The chromatographic separations were achieved on Waters Symmetry Shield(TM) C18 column (150 × 4.6 mm, 5 µm) using 3.5 mm ammonium acetate (pH 3.5)-acetonitrile (10:90, v/v) as mobile phase at a flow rate of 0.75 mL/min. The present method was successfully applied for therapeutic drug monitoring of aspirin and clopidogrel in 67 patients with coronary artery disease.

Dithiocarbamate-thiourea hybrids useful as vaginal microbicides also show reverse transcriptase inhibition: design, synthesis, docking and pharmacokinetic studies.

Prophylactic prevention is considered as the most promising strategy to tackle STI/HIV. Twenty-five dithiocarbamate-thiourea hybrids (14-38) were synthesized as woman controlled topical vaginal microbicides to counter Trichomonas vaginalis and sperm along with RT inhibition potential. The four promising compounds (18, 26, 28 and 33) were tested for safety through cytotoxic assay against human cervical cell line (HeLa) and compatibility with vaginal flora, Lactobacillus. Docking study of most promising vaginal microbicide (33) revealed that it docked in a position and orientation similar to known reverse transcriptase inhibitor Nevirapine. The preliminary in vivo pharmacokinetics of compound 33 was performed in NZ-rabbits to evaluate systemic toxicity in comparison to Nonoxynol-9.

Pharmacokinetics and tissue distribution study of novel potent antiplatelet agent S007-867 in mice using HPLC-MS/MS.

1. S007-867 is a novel antiplatelet agent that shows promising in vitro and in vivo efficacy. For further development and better pharmacological elucidation, we characterized pharmacokinetics and tissue distribution of S007-867 in a mouse model. 2. A sensitive, selective and robust LC-MS/MS method was developed and validated in the mouse plasma and tissue for quantification of S007-867. The chromatographic separation was performed on Waters Symmetry Shield C18 column (150 × 4.6 mm, 5 µm) using methanol and ammonium acetate buffer. 3. S007-867 was rapidly absorbed and distributed to various tissues. Following single oral administration of S007-867 in the mouse, the concentration was in the order of C intestine > C liver > C kidney > C heart > C spleen > C lungs > C brain. Tissue to plasma area under the plasma curve ratio suggested that the maximum amount of drug was found in the intestine and liver. Half life of S007-867 was found longer in the heart (8.08 h), spleen (∼ 7.94 h) and kidney (∼ 15.41 h) as compared with other tissues. 4. The preclinical pharmacokinetics and tissue distribution data obtained using this LC-MS/MS method are expected to assist the future clinical investigations of S007-867 as a promising antiplatelet agent.

Synthesis and evaluation of new 3-phenylcoumarin derivatives as potential antidepressant agents.

A series of amine substituted 3-phenyl coumarin derivatives were designed and synthesized as potential antidepressant agents. In preliminary screening, all compounds were evaluated in forced swimming test (FST), a model to screen antidepressant activity in rodents. Among the series, compounds 5c and 6a potentially decreased the immobility time by 73.4% and 79.7% at a low dose of 0.5 mg/kg as compared to standard drug fluoxetine (FXT) which reduced the immobility time by 74% at a dose of 20 mg/kg, ip. Additionally, these active compounds also exhibited significant efficacy in tail suspension test (TST) (another model to screen antidepressant compounds). Interestingly, rotarod and locomotor activity tests confirmed that these two compounds do not have any motor impairment effect and neurotoxicity in mice. Our studies demonstrate that the new 3-phenylcoumarin derivatives may serve as a promising antidepressant lead and hence pave the way for further investigation around this chemical space.

Integrated Population Exposure-Response of Dolutegravir in HIV-1 Supports Bridging of Clinical Response Influenced by Relevant Intrinsic and Extrinsic Patient Characteristics.

Dolutegravir (DTG) is a human immunodeficiency virus type 1 (HIV-1) integrase strand transfer inhibitor indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection in adults and pediatric subjects aged at least 4 weeks. The present work aimed to characterize the viral response based on a pooled analysis of exposure-response (E-R) from five studies in treatment-experienced and integrase-resistant (INI-r) patients infected with HIV-1. Importantly, model-based simulations of the E-R relationships with DTG provided insight into the clinical relevance of known intrinsic (e.g., sub-population with Q148-driven integrase mutation) and extrinsic (food, enzyme inducers, and metal cation-containing products) factors expected to influence the DTG E-R relationship. Model-based post hoc exposure metrics (C min and C avg) were incorporated into a mechanistic population viral dynamic model describing the short-term effect of DTG on log10 HIV-1 RNA viral load over 8 or 10 days. In addition, the impact of DTG in combination with background ARTs on the 24-week HIV RNA response was also assessed using logistic regression. There was good concordance between model-based predictions and observed virologic response on day 10 and week 24. The E-R model-based simulations exploring the potential impact of a higher dose (100 mg b.i.d.) of DTG in subpopulations experiencing exposure changes due to covariates did not show clinically relevant changes in virological response compared with the approved 50 mg b.i.d. clinical dose. Overall, our study confirmed the current recommendation of dolutegravir 50 mg b.i.d. in the integrase inhibitor-resistant (INI-r) population.

Population Pharmacokinetic Analysis of Dolutegravir in Treatment-Experienced Adults Living with HIV-1.

The World Health Organization has recommended the use of dolutegravir (DTG) for both first and second-line antiretroviral treatment in both adults and children down to 4 weeks of age. We developed a population pharmacokinetic(PopPK) model following oral administration of DTG 50 mg QD and 50 mg BID in HIV-infected treatment-experienced adults (607) based on pooled data from four phase 2/3 trials. DTG population pharmacokinetics are described by a one-compartment model with first-order absorption, absorption lag-time, and first-order elimination. The PopPK parameter estimates were apparent oral clearance (CL/F) = 1.00 L/h, apparent volume of distribution (V/F) = 18.9 L, absorption rate constant (Ka) = 1.99 per hour, and absorption lag time = 0.333 h, respectively. The final model included inter-individual and inter-occasion variability on apparent clearance (CL/F). Weight, smoking status, use of metabolic inducers as part of background antiretroviral therapy (ART) classified by their level of induction, use of atazanavir or atazanavir-ritonavir as part of background ART, and albumin level were predictors of CL/F; weight and albumin level were predictors of V/F; and sex and concomitant use of metal cation-containing vitamin/mineral supplements were predictors of relative bioavailability (F). The current model-based analysis suggests that the DTG dose adjustment is not required based on the demographics, laboratory values, smoking status, concomitant use of mild metabolic inducers or inhibitors in the background therapy, or use of metal cation-containing vitamin/mineral supplements because these covariate effects are not predicted to have a clinically relevant impact on safety and efficacy.

Population Pharmacokinetic Modeling of Abacavir/Dolutegravir/Lamivudine to Support a Fixed-Dose Combination in Children with HIV-1.

INTRODUCTION: Once-daily fixed-dose combinations (FDC) containing abacavir (ABC), dolutegravir (DTG), and lamivudine (3TC) have been approved in the US for adults and children with HIV weighing ≥ 6 kg. This analysis assessed the ability of previously developed ABC, DTG, and 3TC pediatric population pharmacokinetic (PopPK) models using multiple formulations to describe and predict PK data in young children using dispersible tablet (DT) and tablet formulations of ABC/DTG/3TC FDC in the IMPAACT 2019 study. METHODS: IMPAACT 2019 was a Phase I/II study assessing the PK, safety, tolerability, and efficacy of ABC/DTG/3TC FDC in children with HIV-1. Intensive and sparse PK samples were collected over 48 weeks. Existing drug-specific pediatric PopPK models for ABC (2-compartment), DTG (1-compartment), and 3TC (1-compartment) were applied to the IMPAACT 2019 drug concentration data without re-estimation (external validation) of PopPK parameters. Drug exposures were then simulated across World Health Organization weight bands for children weighing ≥ 6 to < 40 kg for each drug and compared with pre-defined exposure target ranges. RESULTS: Goodness-of-fit and visual predictive check plots demonstrated that the previously developed pediatric PopPK models sufficiently described and predicted the data. Thus, new PopPK models describing the IMPAACT 2019 data were unnecessary. Across weight bands, the predicted geometric mean (GM) for ABC AUC0-24 ranged from 14.89 to 18.50 µg*h/ml, DTG C24 ranged from 0.74 to 0.95 µg/ml, and 3TC AUC0-24 ranged from 10.50 to 13.20 µg*h/ml. These exposures were well within the pre-defined target ranges set for each drug. CONCLUSION: This model-based approach leveraged existing pediatric data and models to confirm dosing of ABC/DTG/3TC FDC formulations in children with HIV-1. This analysis supports ABC/DTG/3TC FDC dosing in children weighing ≥ 6 kg.

A Model-Based Approach Supporting Abacavir/Dolutegravir/Lamivudine Fixed-Dose Combination Approval in Children Living with HIV-1.

In March 2022, the US Food and Drug Administration expanded indications of TRIUMEQ, a once-daily fixed-dose combination (FDC) containing abacavir (ABC), dolutegravir (DTG), and lamivudine (3TC) to include pediatric patients weighing at least 10 kg for the treatment of HIV-1. Prior to this extension, the ABC 600 mg/DTG 50 mg/3TC 300 mg FDC tablet was approved for use only in the adult/adolescent population, weighing ≥40 kg while each component of the FDC was approved for its use in pediatric patients at least 3 months and older. A new child-friendly formulation was developed as an FDC dispersible tablet (DT) of ABC 60 mg/DTG 5 mg/3TC 30 mg for pediatric patients with a body weight ≥ 6 kg. The present work demonstrates the utility of applying a model-informed drug development (MIDD) approach to expedite ABC/DTG/3TC FDC approval for pediatric patients (≥10 to <40 kg) based on data from the existing individual components and formulation bridging. Population pharmacokinetic models developed for pediatric participants across all three components of ABC/DTG/3TC FDC were employed for exposure prediction and incorporated relative bioavailability data. The predicted plasma exposures of ABC, DTG, and 3TC for FDC doses were consistent with those observed for the single entities in pediatric and adult studies. Thus, safety and efficacy observed in the individual component studies could be adequately extrapolated to the FDC that results in similar exposure. The current work demonstrates the significance of MIDD approaches in facilitating expedited access to child-friendly formulations in the HIV-1 therapeutic area.

Advancing research and development of anti-infectives for children with a focus on antiretroviral therapy: A clinical development perspective.

The HIV treatment landscape for adults has progressed dramatically in recent decades; however, paediatric populations continue to experience delayed and limited access to effective and safe antiretroviral therapy options. Despite current incentive programmes, formulation research and development and approved drug dosing for children have been limited, particularly for neonates (aged <4 wk). Regulatory approval of drug formulations and dosing in children may lag behind adult approvals by years. Formulation and trial design adjustments complicate paediatric drug development, all of which are vital to accommodate for physiological differences, organ maturation, and rapid weight gain, which are most significant in the youngest children. To facilitate more rapid anti-infective drug development for paediatric populations, regulatory agencies provide guidelines that include extrapolating efficacy and safety data from relevant populations; using pharmacokinetic (PK) bridging and modelling to reduce sample sizes and limit the number of PK studies needed before efficacy analyses; and enrolling age- or weight-based cohorts in parallel rather than sequentially for clinical trials. Ensuring access to approved drugs poses an additional challenge, as uncertainty in demand leads to manufacturing and supply complexity with potentially higher costs that can be a barrier to uptake. Here we summarise challenges in drug development for children living with HIV, which are not unique to antiretrovirals. We aim to propose strategies for how model-based approaches and global partnerships can overcome some of these barriers to accelerate paediatric drug development, with particular reference to HIV, and how lessons learnt from HIV could be extended to other anti-infectives.

Dosing Cefazolin for Surgical Site Infection Prophylaxis in Adolescent Idiopathic Scoliosis Surgery: Intermittent Bolus or Continuous Infusion?-A Pilot Study.

Background: Cefazolin may minimize the risk of surgical site infection (SSI) following posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). Cefazolin dosing recommendations vary and there is limited evidence for achieved tissue concentrations. Methods: We performed a randomized, controlled, prospective pharmacokinetic pilot study of 12 patients given cefazolin by either intermittent bolus (30 mg/kg every 3 h) or continuous infusion (30 mg/kg bolus followed by 10/mg/kg per hour) during PSF for AIS. Results: Patients were well matched for demographic and perioperative variables. While total drug exposure, measured as area-under-the-curve (AUC), was similar in plasma for bolus and infusion dosing, infusion dosing achieved greater cefazolin exposure in subcutaneous and muscle tissue. Using the pharmacodynamic metric of time spent above minimal inhibitory concentration (MIC), both bolus and infusion dosing performed well. However, when targeting a bactericidal concentration of 32 µg/mL, patients in the bolus group spent a median of 1/5 and 1/3 of the typical 6 h operative time below target in subcutaneous and muscle tissue, respectively. Conclusions: We conclude that intraoperative determination of cefazolin tissue concentrations is feasible and both bolus and infusion dosing of cefazolin achieve concentrations in excess of typical MICs. Infusion dosing appears to more consistently achieve bactericidal concentrations in subcutaneous and muscle tissues.

Bridging dolutegravir clinical viral response across doses and formulations using model-based exposure-response analysis in pediatrics.

OBJECTIVE: Dolutegravir (DTG) is a once-daily HIV-1 integrase inhibitor approved for the treatment of HIV-1 infection in adults and children from 4 weeks of age. The posology of DTG in children has been driven by exposure-matching relative to the adult dose for efficacy and safety. However, higher variability in pediatric exposures raises concern that efficacy may not be reliably extrapolated from adult trials. Therefore, we evaluated the relationship between DTG exposure and virologic response in children. DESIGN/METHODS: A population exposure-response analysis using logistic regression for virologic response was undertaken based on DTG exposure and covariate data from 146 pediatric participants with HIV-1 from age at least 4 weeks to less than 18 years treated for up to 48 weeks with DTG in IMPAACT P1093 study. RESULTS: None of the DTG exposure metrics were predictive of virologic response over the range of exposures in this analysis. Of the covariates tested, viral load at least 100 000 copies/ml at enrolment was a significant predictor of virologic response showing a lower probability of achieving a virologic response of HIV-1 RNA less than 50 copies/ml compared with participants with viral load less than 100 000 copies/ml at enrolment. Baseline viral load was also a significant predictor at week 48 whereby the probability of achieving a virologic response at week 48 decreased with increasing baseline viral load. CONCLUSION: This exposure-response analysis suggests that DTG exposures in children are all above the plateau of the exposure-response relationship. These results suggest that matching pediatric pharmacokinetic exposure parameters to those in adults is a reasonable approach for dose determination of DTG-containing formulations in pediatrics.

Effect of Food on the Pediatric Dispersible Tablet Formulations of TRIUMEQ and DOVATO in Healthy Adult Participants.

This randomized food effect study in healthy adult participants examined dispersible tablet formulations of fixed-dose combinations of dolutegravir/abacavir/lamivudine (TRIUMEQ) and dolutegravir/lamivudine (DOVATO). While adult tablet formulations of these combinations are currently approved for the treatment of human immunodeficiency virus, alternate formulations for children are urgently needed to facilitate appropriate pediatric dosing for patients who may have difficulty swallowing a conventional tablet. This study compared the effect of a high-fat, high-calorie meal on the pharmacokinetics, safety, and tolerability of dispersible tablet (DT) formulations of the two-drug and three-drug regimens, with administration under fasting conditions. Both the two-drug and three-drug dispersible tablet formulations, administered under fasting conditions and following a high-fat, high-calorie meal, were well tolerated in healthy participants. There were no clinically relevant differences in drug exposure for either regimen when administered with a high-fat meal as compared to under fasting conditions. Safety observations were similar for both treatments, either in the fed or fasted state. Both TRIUMEQ DT and DOVATO DT formulations can be administer with or without food.

Population Pharmacokinetic Modeling of Dolutegravir to Optimize Pediatric Dosing in HIV-1-Infected Infants, Children, and Adolescents.

BACKGROUND AND OBJECTIVE: HIV treatment options remain limited in children. Dolutegravir is a potent and well-tolerated, once-daily HIV-1 integrase inhibitor recommended for HIV-1 infection in both adults and children down to 4 weeks of age. To support pediatric dosing of dolutegravir in children, we used a population pharmacokinetic model with dolutegravir data from the P1093 and ODYSSEY clinical trials. The relationship between dolutegravir exposure and selected safety endpoints was also evaluated. METHODS: A population pharmacokinetic model was developed with data from P1093 and ODYSSEY to characterize the pharmacokinetics and associated variability and to evaluate the impact of pharmacokinetic covariates. The final population pharmacokinetic model simulated exposures across weight bands, doses, and formulations that were compared with established adult reference data. Exploratory exposure-safety analyses evaluated the relationship between dolutegravir pharmacokinetic parameters and selected clinical laboratory parameters and adverse events. RESULTS: A total of N = 239 participants were included, baseline age ranged from 0.1 to 17.5 years, weight ranged from 3.9 to 91 kg, 50% were male, and 80% were black. The final population pharmacokinetic model was a one-compartment model with first-order absorption and elimination, enabling predictions of dolutegravir concentrations in the pediatric population across weight bands and doses/formulations. The predicted geometric mean trough concentration was comparable to the adult value following a 50-mg daily dose of dolutegravir for all weight bands at recommended doses. Body weight, age, and formulation were significant predictors of dolutegravir pharmacokinetics in pediatrics. Additionally, during an exploratory exposure-safety analysis, no correlation was found between dolutegravir exposure and selected safety endpoints or adverse events. CONCLUSIONS: The dolutegravir dosing in children ≥ 4 weeks of age on an age/weight-band basis provides comparable exposures to those historically observed in adults. Observed pharmacokinetic variability was higher in this pediatric population and no additional safety concerns were observed. These results support the weight-banded dosing of dolutegravir in pediatric participants currently recommended by the World Health Organization.

Pharmacokinetics, safety, and tolerability of dispersible and immediate-release abacavir, dolutegravir, and lamivudine tablets in children with HIV (IMPAACT 2019): week 24 results of an open-label, multicentre, phase 1-2 dose-confirmation study.

BACKGROUND: Child-friendly fixed-dose combination (FDC) antiretroviral therapy (ART) options are limited. We evaluated the pharmacokinetics, safety, and tolerability of dispersible and immediate-release FDC abacavir, dolutegravir, and lamivudine taken once per day in children younger than 12 years with HIV. METHODS: IMPAACT 2019 was an international, phase 1-2, multisite, open-label, non-comparative dose-confirmation study of abacavir, dolutegravir, and lamivudine in children younger than 12 years. Participants were enrolled across five weight bands: those weighing 6 kg to less than 25 kg received abacavir (60 mg), dolutegravir (5 mg), and lamivudine (30 mg) dispersible tablets (three to six tablets depending on body weight), and those weighing 25 kg to less than 40 kg received abacavir (600 mg), dolutegravir (50 mg), and lamivudine (300 mg) in an immediate-release tablet. At entry, participants were ART naive or ART experienced and virologically suppressed on stable ART for 6 months or more. Dose confirmation was based on pharmacokinetic and safety criteria in the first five to seven participants in each weight band to week 4; all participants were followed up to week 48. We present the results for the primary objectives to assess pharmacokinetics, confirm dosing, and evaluate safety through 24 weeks across all weight bands. The trial is registered with ClinicalTrials.gov (NCT03760458). FINDINGS: 57 children were enrolled and initiated study drug (26 [46%] female and 31 [54%] male; 37 [65%] Black, 18 [32%] Asian, and 1 [2%] had race reported as unknown). Within each weight band, 6 kg to less than 10 kg, 10 kg to less than 14 kg, 14 kg to less than 20 kg, 20 kg to less than 25 kg, and 25 kg or higher: the geometric mean dolutegravir area under the concentration time curve over the 24 h dosing interval (AUC0-24 h) was 75·9 h·µg/mL (33·7%), 91·0 h·µg/mL (36·5%), 71·4 h·µg/mL (23·5%), 84·4 h·µg/mL (26·3%), and 71·8 h·µg/mL (13·9%); dolutegravir concentrations 24 h after dosage (C24 h) were 0·91 µg/mL (67·6%), 1·22 µg/mL (77·5%), 0·79 µg/mL (44·2%), 1·35 µg/mL (95·5%), and 0·98 µg/mL (27·9%); abacavir AUC0-24 h was 17·7 h·µg/mL (38·8%), 19·8 h·µg/mL (50·6%), 15·1 h·µg/mL (40·3%), 17·4 h·µg/mL (19·4%), and 25·7 h·µg/mL (14·6%); lamivudine AUC0-24 h was 10·7 h·µg/mL (46·0%), 14·2 h·µg/mL (23·9%), 13·0 h·µg/mL (15·6%), 14·5 h·µg/mL (16·6%), and 21·7 h·µg/mL (26·2%), respectively. Pharmacokinetic targets and safety criteria were met within each weight band, and thus dosing of abacavir, dolutegravir, and lamivudine was confirmed at the originally selected doses. 54 (95%) of participants were treatment experienced and all who continued taking the study drug remained virologically suppressed (<200 copies per mL) through week 24. Virological suppression was achieved in two of three participants who were ART naive by week 24. There were no grade 3 or higher adverse events related to abacavir, dolutegravir, and lamivudine and no discontinuations because of toxicity to week 24. Both formulations were well tolerated. INTERPRETATION: Dosing of abacavir, dolutegravir, and lamivudine was confirmed in children weighing 6 kg to less than 40 kg, and both FDC formulations were safe, well tolerated, and efficacious through 24 weeks of treatment. These findings support global efforts to expand the availability of FDC abacavir, dolutegravir, and lamivudine to children with HIV. FUNDING: National Institute of Allergy and Infectious Diseases, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute of Mental Health, ViiV Healthcare, and GlaxoSmithKline.

Tobacco smoke exposure enhances reward sensitivity in male and female rats.

RATIONALE: Systemic administration of the tobacco smoke constituent nicotine stimulates brain reward function in rats. However, it is unknown if the inhalation of tobacco smoke affects brain reward function. OBJECTIVES: These experiments investigated if exposure to smoke from high-nicotine SPECTRUM research cigarettes increases reward function and affects the rewarding effects of nicotine in adult male and female Wistar rats. METHODS: Reward function after smoke or nicotine exposure was investigated using the intracranial self-stimulation (ICSS) procedure. A decrease in reward thresholds reflects an increase in reward function. In the first experiment, the rats were exposed to tobacco smoke for 40 min/day for 9 days, and the rewarding effects of nicotine (0.03-0.6 mg/kg) were investigated 3 weeks later. In the second experiment, the dose effects of tobacco smoke exposure (40-min sessions, 1-4 cigarettes burnt simultaneously) on reward function were investigated. RESULTS: Tobacco smoke exposure did not affect the nicotine-induced decrease in reward thresholds or response latencies in male and female rats. Smoke exposure lowered the brain reward thresholds to a similar degree in males and females and caused a greater decrease in latencies in females. There was a positive relationship between plasma nicotine and cotinine levels and the nicotine content of the SPECTRUM research cigarettes. Similar smoke exposure conditions led to higher plasma nicotine and cotinine levels in female than male rats. CONCLUSION: These findings indicate that tobacco smoke exposure enhances brain reward function but does not potentiate the rewarding effects of nicotine in male and female rats.

Rapid and Simultaneous Analysis of Multiple Classes of Antimicrobial Drugs by Liquid Chromatography-Tandem Mass Spectrometry and Its Application to Routine Biomedical, Food, and Soil Analyses.

Antimicrobial agents (AMAs) are widely exploited nowadays to meet the high demand for animal-derived food. It has a significant impact on the food chain whose end consumers are human beings. The burden of AMAs on humans comes from either meat or crops cultivated on soil containing high residual antibiotics, which are responsible for the global crisis of antibiotic resistance. Thus, the objective of this study was to design a selective and sensitive liquid chromatography-mass spectrometry (LC-MS)/MS-based simultaneous bioanalytical method for estimation of twenty AMAs in human plasma, raw meat, and soil samples. The selective extraction of all analytes from the above matrices was performed by the solid-phase extraction clean-up method to overcome the interferences. Analytes were separated on a Waters Symmetry Shield C18 (150 × 4.6 mm2, 5 µm) column, using an isocratic solvent system of methanol-0.5% formic acid (80:20, v/v) with 0.75 mL/min flow rate. The average extraction recoveries for all analytes in plasma were ranged from 42.0 to 94.0% with relative standard deviations (RSDs) below ±15%. All of the validation parameters are in accordance with the United State Food and Drug Administration (USFDA) guidelines. Moreover, the method was also valid for a broad plasma concentration range and can be proposed as an excellent method for routine pharmacokinetic studies, therapeutic drug monitoring, clinical analysis, and detection and quantitation of AMA remnants in raw meat as a standard quality control test for human consumption.

Carvacrol loaded nanostructured lipid carriers as a promising parenteral formulation for leishmaniasis treatment.

Leishmaniasis are a group of neglected infectious diseases caused by protozoa of the genus Leishmania with distinct presentations. The available leishmaniasis treatment options are either expensive and/or; cause adverse effects and some are ineffective for resistant Leishmania strains. Therefore, molecules derived from natural products as the monoterpene carvacrol, have attracted interest as promising anti-leishmania agents. However, the therapeutic use of carvacrol is limited due to its low aqueous solubility, rapid oxidation and volatilization. Thus, the development of nanostructured lipid carriers (NLCs) was proposed in the present study as a promising nanotechnology strategy to overcome these limitations and enable the use of carvacrol in leishmaniasis therapy. Carvacrol NLCs were obtained using a warm microemulsion method, and evaluated regarding the influence of lipid matrix and components concentration on the NLCs formation. NLCs were characterized by DSC and XRD as well. In addition, to the in vitro carvacrol release from NLCs, the in vitro cytotoxicity and leishmanicidal activity assays, and the in vivo pharmacokinetics evaluation of free and encapsulated carvacrol were performed. NLCs containing carvacrol were obtained successfully using a warm microemulsion dilution method. The NLCs formulation with the lowest particle size (98.42 ± 0.80 nm), narrowest size distribution (suitable for intravenous administration), and the highest encapsulation efficiency was produced by using beeswax as solid lipid (HLB=9) and 5% of lipids and surfactant. The in vitro release of carvacrol from NLCs was fitted to the Korsmeyer and Peppas, and Weibull models, demonstrating that the release mechanism is probably the Fickian diffusion type. Moreover, carvacrol encapsulation in NLCs provided a lower cytotoxicity in comparison to free carvacrol (p<0.05), increasing its in vitro leishmanicidal efficacy in the amastigote form. Finally, the in vivo pharmacokinetics of carvacrol after IV bolus administration suggests that this phenolic monoterpene undergoes enterohepatic circulation and therefore presented a long half-life (t1/2) and low clearance (Cl). In addition, C0, mean residence time (MRT) and Vdss of encapsulated carvacrol were higher than free carvacrol (p < 0.05), favoring a higher distribution of carvacrol in the target tissues. Thus, it is possible to conclude that the developed NLCs are a promising delivery system for leishmaniasis treatment.

Bioanalytical method development and validation for determination of fibroblast growth factor peptide and its application to pharmacokinetic studies.

Fibroblast growth factor peptide (FGF-P) is a polypeptide analog of FGF-2 that could be a potential mitigation and treatment agent for radiation syndromes. Prior to conducting preclinical pharmacokinetics, we developed and validated the LC-MS/MS bioanalytical method for determination of FGF-P in rat plasma for the first time. FGF-P was extracted from rat plasma using the protein precipitation technique followed liquid-liquid extraction using dichloromethane as a solvent. The mobile phases consisted of two components: (a) 0.1% formic acid in water; and (b) acetonitrile: 0.1% formic acid in water (95:5) under gradient elution. The validated method was also successfully applied to a pharmacokinetic study of FGF-P (10 mg/kg, intravenous) in Wistar rats. The method proved to be specific, accurate, precise, and linear over the concentration range of 2-500 ng/mL with coefficient of determination greater than 0.99 in all validation batches. The within-run and between-run accuracy was 87.97-115.00% with a precision of less than 14%. The mean recoveries ranged from 88.14% to 101.73%. The stability of the compound in plasma samples was proven under various storage conditions. After intravenous administration of FGF-P (10 mg/kg) the C0 was 70.4 µg/mL and the AUC was 86.2 µg*min/mL.