QbD Based Formulation Development and Optimisation of Ozenoxacin Topical Nano-Emulgel and Efficacy Evaluation Using Impetigo Mice Model

To formulate and optimize Ozenoxacin nano-emulsion using Quality by Design (QbD) concept by means of Box-Behnken Design (BBD) and converting it to a gel to form Ozenoxacin nano-emulgel followed by physico-chemical, in-vitro, ex-vivo and in-vivo evaluation. This study demonstrates the application of QbD methodology for the development and optimization of an effective topical nanoemulgel formulation for the treatment of Impetigo focusing on the selection of appropriate excipients, optimization of formulation and process variables, and characterization of critical quality attributes. BBD was used to study the effect of "% of oil, % of Smix and homogenization speed" on critical quality attributes "globule size and % entrapment efficiency" for the optimisation of Ozenoxacin Nano-emulsion. Ozenoxacin loaded nano-emulgel was characterized for "description, identification, pH, specific gravity, amplitude sweep, viscosity, assay, organic impurities, antimicrobial effectiveness testing, in-vitro release testing, ex-vivo permeation testing, skin retention and in-vivo anti-bacterial activity". In-vitro release and ex-vivo permeation, skin retention and in-vivo anti-bacterial activity were found to be significantly (p < 0.01) higher for the nano-emulgel formulation compared to the innovator formulation (OZANEX™). Antimicrobial effectiveness testing was performed and found that even at 70% label claim of benzoic acid is effective to inhibit microbial growth in the drug product. The systematic application of QbD principles facilitated the successful development and optimization of a Ozenoxacin Nano-Emulsion. Optimised Ozenoxacin Nano-Emulgel can be considered as an effective alternative and found to be stable at least for 6 months at 40 °C / 75% RH and 30 °C / 75% RH.

[Pharmacokinetics and pharmacodynamics of rebamipide. New possibilities of therapy: A review]

The MedLine database contains 570 publications, including 71 randomized clinical trials and 6 meta-analyses on the rebamipide molecule in 2022. Indications for the use of rebamipide are gastric ulcer, chronic gastritis with hyperacidityin the acute stage, erosive gastritis, prevention of damage to the gastrointestinal mucosa while taking non-steroidal anti-inflammatory drugs, eradication of Helicobacter pylori. Currently trials are studying the efficacy and safety of the drug in gouty and rheumatoid arthritis, osteoarthritis, Sjögren's syndrome, bronchial asthma, vitiligo, atherosclerosis, diseases of the kidneys and liver; using in traumatology to accelerate bone regeneration; in ophthalmology to improve the regeneration of corneal epithelium; in oncology to reduce inflammatory changes in the oral mucosa after chemoradiotherapy. The review article is about the main pharmacokinetic and pharmacodynamic characteristics of rebamipide. A detailed understanding of pharmacodynamics and pharmacokinetics allows for individual selection of therapy based on the characteristics of the patient's body - gender, age, comorbidities; choose the optimal route of administration and dosing regimen; predict adverse effects and drug interactions; be determined with new clinical indications.

Population Pharmacokinetic Modeling and Exposure-Response Analysis for Aripiprazole Once Monthly in Subjects With Schizophrenia

An intramuscular formulation of aripiprazole monohydrate dosed once monthly (AOM) was developed to address nonadherence with the approved oral tablets. A 3-compartment linear population pharmacokinetic model for oral and AOM doses was developed; relative bioavailability was estimated for AOM relative to oral dosing and body mass index and sex were significant predictors of AOM absorption rate constant (longer absorption half-life for women and absorption half-life increases with increasing body mass index). Aripiprazole apparent oral clearance for subjects with cytochrome P450 (CYP) 2D6 poor metabolizer status and in the presence of strong CYP2D6 inhibitors was approximately half that of subjects with CYP2D6 extensive metabolizer status and 24% lower in the presence of strong CYP3A4 inhibitors. Simulations of the population pharmacokinetics were conducted to evaluate the effect of different dose initiation strategies for AOM, the effects of CYP2D6 metabolizer status, coadministration of CYP2D6 and CYP3A4 inhibitors, and missed doses. An exposure-response model with an exponential hazard function of the model-predicted minimum concentration (C_min ) described the time to relapse. The hazard ratio (95% confidence interval) was 4.41 (2.89-6.75). Thus, a subject with a diagnosis of schizophrenia and C_min  ≥ 95 ng/mL is 4.41 times less likely to relapse relative to a subject with C_min  < 95 ng/mL.

Engineering a Remedy to Modulate and Optimize Biopharmaceutical Properties of Rebamipide by Synthesizing New Cocrystal: In Silico and Experimental Studies

PURPOSE

Rebamipide (REB) a potent anti-ulcer agent, has not been exploited to its full potential, owing to it extremely poor solubility, leading to highly diminutive bioavailability (<10%). The purpose is to carry out its solid-state modification.

METHOD

Cocrystallisation was done with three GRAS coformers namely citric acid (CA), 3,4-dihydroxybenzoic acid (DHBA) and oxalic acid (OXA) employing the liquid-assisted grinding method. Cocrystal formation was based upon amide-carboxyl and amide-hydroxyl supramolecular synthons. Characterization of novel cocrystals i.e. RCA, RDHBA and ROXA was carried out by DSC, PXRD and additionally by FT-IR spectroscopy. Chemical structures have been determined utilizing the PXRD pattern by Material Studio®. Furthermore, cocrystals were subjected to solubility and intrinsic dissolution rate (IDR) evaluation. Also, pharmacodynamic and pharmacokinetic studies were performed and compared with pure rebamipide.

RESULT

The appearances of a single sharp melting endotherm in DSC, along with novel characteristic peaks in PXRD infer the existence of a new crystalline form. Shifting in characteristic vibrations in FT-IR spectroscopy supports the establishment of distinct hydrogen-bonded networks. Structural determination revealed that RCA crystallizes in 'Bb2b' space groups whereas RDHBA in 'P1' and ROXA crystallize out in the 'P-1' space group. All the cocrystals exhibited superior apparent solubility and almost 7-13 folds increase in IDR. Furthermore, 1.6-2.5 folds enhancement in relative bioavailability and remarkable amplification in anti-ulcer, anti-inflammatory and the antioxidant potential of these cocrystals were observed.

CONCLUSION

The study ascertains the advantages of cocrystallization, with RCA showing greatest potential and suggests a viable alternative approach for improved formulation of rebamipide.

Uptake of Ozenoxacin and Other Quinolones in Gram-Positive Bacteria

The big problem of antimicrobial resistance is that it requires great efforts in the design of improved drugs which can quickly reach their target of action. Studies of antibiotic uptake and interaction with their target it is a key factor in this important challenge. We investigated the accumulation of ozenoxacin (OZN), moxifloxacin (MOX), levofloxacin (LVX), and ciprofloxacin (CIP) into the bacterial cells of 5 species, including Staphylococcus aureus (SA4-149), Staphylococcus epidermidis (SEP7602), Streptococcus pyogenes (SPY165), Streptococcus agalactiae (SAG146), and Enterococcus faecium (EF897) previously characterized.The concentration of quinolone uptake was estimated by agar disc-diffusion bioassay. Furthermore, we determined the inhibitory concentrations 50 (IC50) of OZN, MOX, LVX, and CIP against type II topoisomerases from S. aureus.The accumulation of OZN inside the bacterial cell was superior in comparison to MOX, LVX, and CIP in all tested species. The accumulation of OZN inside the bacterial cell was superior in comparison to MOX, LVX, and CIP in all tested species. The rapid penetration of OZN into the cell was reflected during the first minute of exposure with antibiotic values between 190 and 447 ng/mg (dry weight) of bacteria in all strains. Moreover, OZN showed the greatest inhibitory activity among the quinolones tested for both DNA gyrase and topoisomerase IV isolated from S. aureus with IC50 values of 10 and 0.5 mg/L, respectively. OZN intracellular concentration was significantly higher than that of MOX, LVX and CIP. All of these features may explain the higher in vitro activity of OZN compared to the other tested quinolones.

Quantitative Method for the Analysis of Ivacaftor, Hydroxymethyl Ivacaftor, Ivacaftor Carboxylate, Lumacaftor, and Tezacaftor in Plasma and Sputum Using Liquid Chromatography With Tandem Mass Spectrometry and Its Clinical Applicability

BACKGROUND

The novel cystic fibrosis transmembrane conductance regulator (CFTR) modulators, ivacaftor, lumacaftor, and tezacaftor, are the first drugs directly targeting the underlying pathophysiological mechanism in cystic fibrosis (CF); however, independent studies describing their pharmacokinetics are lacking. The aim of this study was to develop a quantification method for ivacaftor and its 2 main metabolites, lumacaftor and tezacaftor, in plasma and sputum using liquid chromatography with tandem mass spectrometry.

METHODS

The developed method used a small sample volume (20 µL) and simple pretreatment method; protein precipitation solution and internal standard were added in one step to each sample. Liquid chromatography with tandem mass spectrometry was performed for a total run time of 6 minutes. The method was validated by assessing selectivity, carryover, linearity, accuracy and precision, dilution, matrix effects, and stability.

RESULTS

The selectivity was good as no interference from matrices was observed. In the concentration range from 0.01 to 10.0 mg/L, calibration curves were linear with a correlation coefficient >0.9997 for all compounds. The within-run and between-run accuracy were between 99.7% and 116% at the lower limit of quantitation (LLOQ) and between 95.8% and 112.9% for all concentrations above LLOQ for all analytes in plasma and sputum. Within-run and between-run precisions were <12.7% for LLOQ and <6.7% for the higher limit of quantitation. Samples were stable, with no significant degradation at examined temperatures and time points. Clinical applicability was revealed by analyzing samples from 2 patients with CF.

CONCLUSIONS

The presented method enables simultaneous quantification of ivacaftor, lumacaftor, and tezacaftor in plasma and sputum and is an improvement over previous methods because it uses smaller sample volumes, a simple pretreatment protocol, and includes tezacaftor. In future studies, it can be applied for examining pharmacokinetics characteristics of new CF transmembrane conductance regulator modulators.

Population Pharmacokinetic Analysis of Indacaterol/Glycopyrronium/Mometasone Furoate After Administration of Combination Therapies Using the Breezhaler® Device in Patients with Asthma

BACKGROUND AND OBJECTIVE

Clinical evidence suggests no clinically relevant pharmacokinetic interactions between indacaterol (IND), glycopyrronium (GLY) and mometasone furoate (MF). A population pharmacokinetic (popPK) analysis was conducted to identify structural models describing systemic pharmacokinetic profiles of IND, GLY and MF, and estimate the effect of covariates on their pharmacokinetics following inhalation as IND/GLY/MF.

METHODS

Pharmacokinetic data from 698 patients with asthma were pooled from two Phase III studies that evaluated IND/MF medium- (150/160 µg) and high-dose (150/320 µg), IND/GLY/MF medium- (150/50/80 μg) and high-dose (150/50/160 μg), and a device bridging Phase II study with MF. One popPK model was developed each for IND, GLY and MF using a nonlinear mixed-effect modelling approach. Maximal and trough plasma concentrations were compared across formulations and studies, including data for IND/GLY from chronic obstructive pulmonary disease (COPD) patients. The effect of predefined covariates on the pharmacokinetics of components was evaluated using a full covariate modelling approach.

RESULTS

The final pharmacokinetic models were two-compartment disposition models with first-order elimination and sequential zero-order/first-order absorption (IND), with bolus administration and first-order elimination (GLY), and with mixed zero-order/first-order absorption and first-order elimination (MF). All model parameters were estimated with good precision (% relative standard error: IND and MF ≤25%; GLY <10%). No clinically relevant covariate effect was observed on the pharmacokinetics of IND, GLY and MF. IND and GLY pharmacokinetic profiles were similar across different formulations.

CONCLUSION

Two-compartment popPK models adequately described the pharmacokinetics of IND, GLY and MF. The effect of covariates was not clinically relevant. The pharmacokinetic profiles of MF were comparable for combination products at corresponding medium- or high-dose inhaled corticosteroids. On a population level, the pharmacokinetics of IND and GLY were comparable between patients with asthma and COPD.

Pharmacokinetics of indacaterol, glycopyrronium and mometasone furoate administered as an inhaled fixed-dose combination in Japanese and Caucasian healthy subjects

BACKGROUND

A once-daily (o.d.) fixed-dose combination of indacaterol acetate (IND), glycopyrronium bromide (GLY), and mometasone furoate (MF) delivered via the Breezhaler® device (IND/GLY/MF) is being developed for treatment of asthma. This study compared steady-state pharmacokinetics of IND, GLY and MF between Japanese and Caucasian male subjects after multiple inhalations of IND/GLY/MF o.d.

METHODS

This was a single-center, open-label, 2-treatment crossover study with a 21-day washout period. Japanese and Caucasian subjects received IND/GLY/MF 150/50/80 μg (inhaled corticosteroid [ICS] medium-dose) or 150/50/160 μg o.d. (ICS high-dose) for 14 days in each period. Pharmacokinetics were characterized up to 24 h post-dose on Days 1 and 14.

RESULTS

In total, 16 Japanese (median age 31 years [range 20-40 years], mean weight 68.3 kg) and 17 Caucasian subjects (median age 27 years [range 21-43 years], mean weight 75.0 kg) were randomized. Geometric mean ratios (Japanese/Caucasian) [90% confidence interval (CI)] for Cmax for IND, GLY and MF at the high ICS dose on Day 14 were 1.31 [1.13, 1.51] 1.38 [1.13, 1.69] and 1.07 [0.969, 1.18], respectively. Geometric mean ratios (Japanese/Caucasian) [90% CI] for AUC0-24h on Day 14 for IND, GLY and MF at the high ICS dose were 1.17 [1.01, 1.35], 1.05 [0.920, 1.20] and 1.15 [1.05, 1.27] respectively. Similar trends were noted for all components for the medium ICS dose treatment. IND/GLY/MF was safe and well tolerated; no AEs suspected to be study drug-related were observed.

CONCLUSION

Pharmacokinetics of IND, GLY and MF (high and medium dose) when delivered as a fixed-dose combination were comparable between Japanese and Caucasian subjects. The IND/GLY/MF combination at the administrated doses was safe and well tolerated in both ethnic groups.

TRIAL REGISTRATION

Japan Registry of Clinical Trial: jRCT2031200227, retrospectively registered on 04, December, 2020.

Variable cellular ivacaftor concentrations in people with cystic fibrosis on modulator therapy

The development of CFTR modulators has transformed the care of patients with cystic fibrosis (CF). Although the clinical efficacy of modulators depends on their concentrations in target tissues, the pharmacokinetic properties of these drugs in epithelia are not utilized to guide patient care. We developed assays to quantitate ivacaftor in cells and plasma from patients on modulator therapy, and our analyses revealed that cellular ivacaftor concentrations differ from plasma concentrations measured concurrently, with evidence of in vivo accumulation of ivacaftor in the cells of patients. While the nature of this study is exploratory and limited by a small number of patients, these findings suggest that techniques to measure modulator concentrations in vivo will be essential to interpreting their clinical impact, particularly given the evidence that ivacaftor concentrations influence the activity and stability of restored CFTR protein.

Single oral dose for HIV pre or post-exposure prophylaxis: user desirability and biological efficacy in macaques

BACKGROUND

Daily oral pre- or post-exposure prophylaxis (PrEP or PEP) is highly effective in preventing HIV infection. However, many people find it challenging to adhere to a daily oral regimen. Chemoprophylaxis with single oral doses of antiretroviral drugs taken before or after sex may better adapt to changing or unanticipated sexual practices and be a desirable alternative to daily PrEP or PEP. We investigated willingness to use a single oral pill before or after sex among men who have sex with men (MSM) and assessed the biological efficacy of a potent antiretroviral combination containing elvitegravir (EVG), emtricitabine (FTC), and tenofovir alafenamide (TAF).

METHODS

Data on willingness to use single-dose PrEP or PEP were obtained from the 2017 cycle of the American Men's Internet Survey (AMIS), an annual online behavioral surveillance survey of MSM in the United States. Antiretroviral drug levels were measured in humans and macaques to define drug distribution in rectal tissue and identify clinically relevant doses for macaque modeling studies. The biological efficacy of a single dose of FTC/TAF/EVG as PrEP or PEP was investigated using a repeat-challenge macaque model of rectal HIV infection.

FINDINGS

Through pharmacokinetic assessment in humans and macaques we found that EVG penetrates and concentrates in rectal tissues supporting its addition to FTC/TAF to boost and extend chemoprophylactic activity. Efficacy estimates for a single oral dose given to macaques 4h before or 2h after SHIV exposure was 91•7%[35•7%-98•9%] and 100%, respectively, compared to 80•1%[13•9%-95•4%] and 64•6%[-19•4%-89•5%] when single doses were given 6 and 24h post challenge, respectively. A two-dose regimen at 24h and 48h after exposure was also protective [77•1%[1•7%-94•7%].

INTERPRETATION

Informed by user willingness, human and macaque pharmacokinetic data, and preclinical efficacy we show that single-dose prophylaxis before or after sex is a promising HIV prevention strategy. Carefully designed clinical trials are needed to determine if any of these strategies will be effective in humans.

FUNDING

Funded by CDC intramural funds, CDC contract HCVJCG2-2016-03948 (to CFK), and a grant from the MAC AIDS Fund and by the National Institutes of Health [P30AI050409] - the Emory Center for AIDS Research (to MZ and TS).

Accumulation and persistence of ivacaftor in airway epithelia with prolonged treatment

BACKGROUND

Current dosing strategies of CFTR modulators are based on serum pharmacokinetics, but drug concentrations in target tissues such as airway epithelia are not known. Previous data suggest that CFTR modulators may accumulate in airway epithelia, and serum pharmacokinetics may not accurately predict effects of chronic treatment.

METHODS

CF (F508del homozygous) primary human bronchial epithelial (HBE) cells grown at air-liquid interface were treated for 14 days with ivacaftor plus lumacaftor or ivacaftor plus tezacaftor, followed by a 14-day washout period. At various intervals during treatment and washout phases, drug concentrations were measured via mass spectrometry, electrophysiological function was assessed in Ussing chambers, and mature CFTR protein was quantified by Western blotting.

RESULTS

During treatment, ivacaftor accumulated in CF-HBEs to a much greater extent than either lumacaftor or tezacaftor and remained persistently elevated even after 14 days of washout. CFTR activity peaked at 7 days of treatment but diminished with further ivacaftor accumulation, though remained above baseline even after washout.

CONCLUSIONS

Intracellular accrual and persistence of CFTR modulators during and after chronic treatment suggest complex pharmacokinetic and pharmacodynamic properties within airway epithelia that are not predicted by serum pharmacokinetics. Direct measurement of drugs in target tissues may be needed to optimize dosing strategies, and the persistence of CFTR modulators after treatment cessation has implications for personalized medicine approaches.

Structure-Activity Relationship Studies of Tetrahydroquinolone Free Fatty Acid Receptor 3 Modulators

Free fatty acid receptor 3 (FFA3, previously GPR41) is activated by short-chain fatty acids, mediates health effects of the gut microbiota, and is a therapeutic target for metabolic and inflammatory diseases. The shortage of well-characterized tool compounds has however impeded progress. Herein, we report structure-activity relationship of an allosteric modulator series and characterization of physicochemical and pharmacokinetic properties of selected compounds, including previous and new tools. Two representatives, 57 (TUG-1907) and 63 (TUG-2015), showed improved solubility and preserved potency. Of these, 57, with EC50 = 145 nM and a solubility of 33 μM, showed high clearance in vivo but is a preferred tool in vitro. In contrast, 63, with EC50 = 162 nM and a solubility of 9 μM, showed lower clearance and seems better suited for in vivo studies. Using 57, we demonstrate for the first time that FFA3 activation leads to calcium mobilization in murine dorsal root ganglia.

1-(Benzo[b]thiophen-4-yl)piperazine Ring Induced Bioactivation of Brexpiprazole in Liver Microsomes: Identification and Characterization of Reactive Conjugates Using Ultra-High-Performance Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry

BACKGROUND AND OBJECTIVES

Brexpiprazole is an atypical antipsychotic approved for the treatment of schizophrenia and major depressive disorders in adults. The structure of brexpiprazole contains well-known structural alerts like a thiophene ring, piperazine ring and quinolinone motifs. Additionally, the literature reveals that its structural analog, aripiprazole, could generate reactive intermediates. However, the bioactivation potential of brexpiprazole is yet unknown. Therefore, this study was planned to identify and characterize reactive adducts of brexpiprazole and its metabolites.

METHODS

Based on the reactivity, the potential atomic sites for a reactive intermediate generation were predicted by a xenosite web predictor tool for glutathione, cyanide, protein and DNA. To study the metabolic activation of brexpiprazole, the drug was individually incubated for 2 h at 37 °C with pooled male rat liver microsomes and human liver microsomes in microcentrifuge tubes fortified with glutathione/N-acetyl cysteine. Nicotinamide adenine dinucleotide phosphate reduced tetrasodium salt was used as a co-factor.

RESULTS

A total of six glutathione and N-acetyl cysteine conjugates of brexpiprazole metabolites were identified and characterized using ultra-high-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry. Reactive metabolite 1 (RM1), RM3, RM4 and RM6 reactive conjugates were formed due to reactive quinone-imine or quinone intermediates, while RM2 and RM5 reactive adducts were generated because of a thiophene-S-oxide intermediate.

CONCLUSION

Brexpirazole is bioactivated due to the presence of a 1-(benzo[b]thiophen-4-yl)piperazine ring in its structure. In contrast to aripiprazole, the quinolinone motif was found latent towards bioactivation in brexpiprazole.

Spatial distribution of elvitegravir and tenofovir in rat brain tissue: Application of matrix-assisted laser desorption/ionization mass spectrometry imaging and liquid chromatography/tandem mass spectrometry

RATIONALE

The complexity of central nervous system (CNS) drug delivery is the main obstacle with the blood-brain barrier (BBB) known to restrict access of most pharmaceutical drugs into the brain. Mass spectrometry imaging (MSI) offers possibilities for studying drug deposition into the CNS.

METHODS

The deposition and spatial distribution of the two antiretroviral drugs elvitegravir and tenofovir in the brain were investigated in healthy female Sprague-Dawley rats following a single intraperitoneal administration (50 mg/kg). This was achieved by the utilization of quantitative liquid chromatography/tandem mass spectrometry (LC/MS/MS) and matrix-assisted laser desorption/ionization (MALDI) MSI.

RESULTS

LC/MS/MS showed that elvitegravir has better BBB penetration, reaching maximum concentration in the brain (C_max brain) of 976.5 ng/g. In contrast, tenofovir displayed relatively lower BBB penetration, reaching C_max brain of 54.5 ng/g. MALDI-MSI showed the heterogeneous distribution of both drugs in various brain regions including the cerebral cortex.

CONCLUSIONS

LC/MS/MS and MALDI-MSI provided valuable information about the relative concentration and the spatial distribution of the two common antiretroviral drugs. This study has also shown the capability of MALDI-MSI for direct visualization of pharmaceutical drugs in situ.

Pharmacokinetic Interactions Between the Fixed-Dose Combinations of Elvitegravir/Cobicistat/Tenofovir Disoproxil Fumarate/Emtricitabine and Elbasvir/Grazoprevir in Healthy Adult Participants

Treatment of individuals coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) requires careful consideration of potential drug-drug interactions. The pharmacokinetic interaction of the HCV fixed-dose combination treatment of elbasvir/grazoprevir (EBR/GZR) when coadministered with the fixed-dose combination HIV treatment of elvitegravir/cobicistat/tenofovir disoproxil fumarate/emtricitabine (EVG/COB/TDF/FTC) was evaluated in 22 healthy adults. In period 1, oral doses of EVG/COB/TDF/FTC (150 mg/150 mg/300 mg/200 mg) were administered once daily for 7 days. In period 2, oral doses of EBR/GZR (50 mg/100 mg) were administered once daily for 10 days. In period 3, oral doses of EVG/COB/TDF/FTC were coadministered with EBR/GZR once daily for 10 days. The pharmacokinetics of EVG/COB/TDF/FTC were not clinically meaningfully altered by concomitant EBR/GZR administration. Geometric mean ratios (90%CIs) for area under the plasma concentration-time curve from time 0 to 24 hours (AUC_0-24 ) in the presence/absence of EBR/GZR were 1.1 (1.0, 1.2) for elvitegravir; 1.1 (1.0, 1.1) for emtricitabine; 1.2 (1.1, 1.2) for tenofovir; and 1.5 (1.4, 1.6) for cobicistat. In comparison, the AUC_0-24 of elbasvir was ∼2 times higher and the AUC_0-24 of grazoprevir was ∼5 times higher following concomitant administration of EVG/COB/TDF/FTC and EBR/GZR. Geometric mean ratios (90%CI) for AUC_0-24 in the presence/absence of EVG/COB/TDF/FTC were 2.2 (2.0, 2.4) for elbasvir and 5.4 (4.5, 6.4) for grazoprevir. Coadministration of EVG/COB/TDF/FTC and EBR/GZR was generally well tolerated in healthy adults in this study. Nevertheless, because of the increased GZR exposure that occurs with coadministration of EVG/COB/TDF/FTC and EBR/GZR, coadministration of this combination is not recommended in those coinfected with HIV and HCV.

Outcomes of Desidustat Treatment in People with Anemia and Chronic Kidney Disease: A Phase 2 Study

BACKGROUND

Desidustat (ZYAN1) is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHI) that stimulates erythropoiesis. Stabilizing HIF via PHI is developing as a new therapeutic approach to treat anemia secondary to chronic kidney disease (CKD). This trial evaluated the safety, tolerability, and efficacy of Desidustat in adult CKD patients with anemia, who were not on dialysis.

METHODS

This was a Phase 2, randomized, double-blind, 6-week, placebo-controlled, dose-ranging, safety and efficacy study. A total of 117 eligible patients were randomized to 4 arms: 100, 150, 200 mg, or placebo. The investigational product was administered every alternate day for 6 weeks in fasting conditions. The primary endpoint was change in hemoglobin (Hb) from baseline to week 6.

RESULTS

Baseline demographics were well balanced among all the treatment arms. In the modified intent-to-treat (mITT) population, a mean Hb increase of 1.57, 2.22, and 2.92 g/dL in Desidustat 100, 150, and 200 mg arms, respectively, was observed post 6 weeks treatment. The responder rate (≥1 g/dL increase) was 66% in 100 mg, 75% in 150 mg, and 83% in 200 mg treatment arms, in the mITT population. Eighteen patients had at least one treatment emergent adverse event (TEAE), and 5 patients reported at least one drug-related mild TEAE. No death or serious adverse event was reported during the trial.

CONCLUSION

There was dose-related increase in Hb across all doses compared to placebo in mITT and per-protocol populations. Desidustat also increased pharmacokinetic parameters Cmax and AUC in dose-related manner. There was no significant change in vital signs, electrocardiographic parameters, or safety laboratory values. Clinical Trial Registration Number CTRI/2017/05/008534 (registered on May 11, 2017).

Clinical Use of Dopamine Modulators as Third-Generation Antipsychotic Agents

When dopamine was identified as a primary target for schizophrenia, the dopamine antagonists, now referred to as first-generation antipsychotics, were added to our pharmacopeia. In the 1990s, with the discovery of risperidone and clozapine, the mechanism of dopamine receptor antagonism was paired with serotonin receptor antagonism to give rise to second-generation antipsychotics. A decade later these mechanisms were further refined to selective dopamine receptors antagonism and serotonin receptors antagonism and agonism to create a modulation or stabilization of dopamine nerve firing in differential ways. This new wave may be referred to as the third generation. The current article reviews the pharmacodynamics and pharmacokinetics of these dopamine modulators. [Journal of Psychosocial Nursing and Mental Health Services, 57(2), 7-11.].

Pharmacokinetics of HIV-Integrase Inhibitors During Pregnancy: Mechanisms, Clinical Implications and Knowledge Gaps

Prevention of mother-to-child transmission of HIV and optimal maternal treatment are the most important goals of antiretroviral therapy in pregnant women with HIV. These goals may be at risk due to possible reduced exposure during pregnancy caused by physiological changes. Limited information is available on the impact of these physiological changes. This is especially true for HIV-integrase inhibitors, a relatively new class of drugs, recommended first-line agents and hence used by a large proportion of HIV-infected patients. Therefore, the objective of this review is to provide a detailed overview of the pharmacokinetics of HIV-integrase inhibitors in pregnancy. Second, this review defines potential causes for the change in pharmacokinetics of HIV-integrase inhibitors during pregnancy. Despite increased clearance, for raltegravir 400 mg twice daily and dolutegravir 50 mg once daily, exposure during pregnancy seems adequate; however, for elvitegravir, the proposed minimal effective concentration is not reached during pregnancy. Lower exposure to these drugs may be caused by increased hormone levels and, subsequently, enhanced drug metabolism during pregnancy. The pharmacokinetics of bictegravir and cabotegravir, which are under development, have not yet been evaluated in pregnant women. New studies need to prospectively assess whether adequate exposure is reached in pregnant women using these new HIV-integrase inhibitors. To further optimize antiretroviral treatment in pregnant women, studies need to unravel the underlying mechanisms behind the changes in the pharmacokinetics of HIV-integrase inhibitors during pregnancy. More knowledge on altered pharmacokinetics during pregnancy and the underlying mechanisms contribute to the development of effective and safe antiretroviral therapy for HIV-infected pregnant women.

Predictive factors for lumacaftor/ivacaftor clinical response

BACKGROUND

Ivacaftor-lumacaftor combination therapy corrects the F508 del-CFTR mutated protein which causes Cystic Fibrosis. The clinical response of the patients treated with the combination therapy is highly variable. This study aimed to determine factors involved in the individual's response to lumacaftor-ivacaftor therapy.

METHODS

Sweat test was assessed at baseline and after 6 months of ivacaftor-lumacaftor treatment in 41 homozygous F508del children and young adults. β-adrenergic peak sweat secretion, nasal potential difference (NPD) and intestinal current measurements (ICM) were performed in patients accepting these tests. Seric level of lumacaftor and ivacaftor were determined and additional CFTR variant were searched.

RESULTS

Sweat chloride concentration significantly decreased after treatment, whereas the β-adrenergic peak sweat response did not vary in 9 patients who underwent these tests. The average level of F508del-CFTR activity rescue reached up to 15% of the normal level in intestinal epithelium, as studied by ICM in 12 patients (p = .03) and 20% of normal in the nasal epithelium in NPD tests performed in 21 patients (NS). There was no significant correlation between these changes and improvements in FEV₁ at 6 months. Serum drug levels did not correlate with changes in FEV₁, BMI-Zscore or other CFTR activity biomarkers. Additional exonic variants were identified in 4 patients. The F87L-I1027T-F508del-CFTR complex allele abolished the lumacaftor corrector effect.

CONCLUSION

This observational study investigates a number of potential factors linked to the clinical response of F508del homozygous patients treated with lumacaftor-ivacaftor combination therapy. Lumacaftor and ivacaftor blood levels are not associated with the clinical response. Additional exonic variants may influence protein correction.

Elvitegravir/cobicistat pharmacokinetics in pregnant and postpartum women with HIV

OBJECTIVE

To evaluate elvitegravir and cobicistat pharmacokinetics during pregnancy compared with postpartum and in infant washout samples after delivery.

DESIGN

Nonrandomized, open-label, parallel-group, multicenter phase-IV prospective study of antiretroviral pharmacokinetics in HIV-infected pregnant women and their children in the United States.

METHODS

Intensive steady-state 24-h pharmacokinetic profiles after 150 mg of elvitegravir and 150 mg of cobicistat given orally in fixed dose combination once-daily were performed during the second trimester, third trimester, and postpartum. Infant washout samples were collected after birth. Elvitegravir and cobicistat were measured in plasma by a validated liquid chromatography with tandem mass spectrometry assay with a lower quantitation limit of 10 ng/ml. A two-tailed Wilcoxon signed-rank test (α = 0.10) was employed for paired within-participant comparisons.

RESULTS

Thirty pregnant women taking elvitegravir and cobicistat once-daily enrolled in the study. Compared with paired postpartum data, elvitegravir AUC0-24 was 24% lower in the second trimester [n = 14, P = 0.058, geometric mean ratios (GMR) = 0.76, 90% confidence interval (CI) 0.57-1.0] and 44% lower in the third trimester (n = 24, P = 0.0001, GMR = 0.56, 90% CI 0.42-0.73), while cobicistat AUC0-24 was 44% lower in the second trimester (n = 14, P = 0.0085, GMR = 0.56, 90% CI 0.37-0.85) and 59% lower in the third trimester (n = 24, P < 0.0001, GMR = 0.41, 90% CI 0.30-0.57). Median cord blood elvitegravir concentration was 540.6 ng/ml and the median ratio of cord blood to maternal plasma elvitegravir concentrations was 0.91.

CONCLUSION

Standard elvitegravir and cobicistat dosing during pregnancy results in significantly lower exposure which may increase the risk of virologic failure and mother-to-child transmission. Additional studies are needed to optimize elvitegravir and cobicistat dosing regimens in pregnant women.

Validated ion pair chromatographic method for simultaneous determination and in vitro dissolution studies of indacaterol and glycopyrronium from inhaled capsule dosage form

A rapid, and highly sensitive analytical method were developed for the simultaneous determination of indacaterol maleate (IND) and glycopyrronium bromide (GLY) in their inhaler capsules. Valid ion-pairing chromatographic (IPC) method was performed for separation of GLY in presence of IND using C₁₈ column and mobile phase consisting of acetonitrile: acidified deionized water (60:40% v/v) containing 0.02% sodium dodecyl sulfate (SDS) adjusted to pH 3.0 using OPA (orthophosphoric acid) isocratically eluted at 2.0 mL/min. Quantitation was achieved with UV detection at 210 nm. Cyproheptadine was used as an internal standard. The retention times were 1.9 and 2.5 min for IND, and GLY, respectively. For the IPC method, the calibration graphs were linear in the range of 0.66-66.0 μg/mL for IND and 0.3-30.0 μg/mL for GLY. The proposed method are rapid, reproducible (R.S.D. <2.0%) and achieves satisfactory resolution between IND and GLY (resolution factor = 4.23). The mean recoveries of the analytes in their inhaler capsule were satisfactory. It was applied successfully to in vitro dissolution testing using Franz diffusion cell and extended to a content uniformity test consistent with the United States Pharmacopoeia (USP) guidelines and were found to be precise and accurate for the capsules studied with acceptance value of 4.53 and 1.39 for IND and GLY, respectively.

Rufloxacin Eyedrops: Effect of Different Formulations on Ocular Pharmacokinetics in Rabbits

PURPOSE

To evaluate the aqueous humor pharmacokinetics of rufloxacin in rabbits after topical administration of different formulations, and to individuate the ones showing the best pharmacokinetic profile.

METHODS

Six formulations were instilled in rabbit eyes: two pH 7.2 suspensions of non-salified rufloxacin base, or zwitterion (RUF), one of which was viscosized with tamarind seed polysaccharide (TSP); two pH 7.2 solutions of RUF obtained using hydroxypropyl-beta-cyclodextrin (CD), one of which was viscosized with TSP; and two pH 5.0 solutions of rufloxacin hydrochloride (RUF-HCl ), one of which was viscosized with TSP. At different times after administration, samples of aqueous humor were withdrawn and analyzed by high-pressure liquid chromatography. The main pharmacokinetic parameters of RUF in the aqueous humor produced by the different formulations were calculated and statistical differences were assessed.

RESULTS

The best results, in terms of aqueous humor bioavailability, were observed with two TSP-viscosized formulations: a solution of the hydrochloride (TSP/RUF-HCl) and a suspension of the base (TSP/RUF), followed by the non-viscosized solution of RUF-HCl. The formulations containing CD-solubilized RUF were much less effective.

CONCLUSIONS

The present data confirm the significant availability-enhancing properties of tamarind seed polysaccharide, and indicate that solubilization of RUF with hydroxypropyl-beta-cyclodextrin (CD/RUF) results in decreased drug availability with respect to standard formulations. Two of the TSP-viscosized formulations (RUF suspension and RUF-HCl solution) produced aqueous humor RUF concentrations in the range of activity against Enterobacteriaceae and Pseudomonas aeruginosa, thus warranting further studies on applications of rufloxacin in ocular therapy.

Pharmacokinetic interactions between cobicistat-boosted elvitegravir and darunavir in HIV-infected patients

Objectives

To evaluate if there are significant drug-drug interactions between cobicistat-boosted elvitegravir and 800 mg darunavir once daily taken simultaneously, as has been suggested previously.

Methods

The study population consisted of three groups of unselected volunteers taking a regimen of elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate (150, 150, 200 and 300 mg, respectively) co-formulated in a single tablet plus 800 mg darunavir (group A); only co-formulated elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate (group B); and cobicistat-boosted darunavir (800 mg darunavir + 150 mg cobicistat) plus two nucleos(t)ide analogues (group C). Elvitegravir, cobicistat and darunavir concentrations at the end of the dosing interval ( C 24 ) were quantified using a validated LC with tandem MS method.

Results

A total of 170 samples were obtained from 24, 32 and 32 patients in groups A, B and C, respectively. In group A, the elvitegravir C 24 were similar to those in group B (233.67 versus 250.39 ng/mL) ( P  =   0.406) and the darunavir C 24 were similar to those in group C (1293.54 versus 1319.34 ng/mL) ( P  =   0.908). The cobicistat C 24 were comparable in groups A and B (20.2 versus 20.9 ng/mL) and slightly higher in group C (27.7 ng/mL) ( P  =   0.059).

Conclusions

The results provide evidence of similar elvitegravir and darunavir C 24 concentrations when these drugs are co-administered as co-formulated elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate plus 800 mg darunavir or dosed separately.

The prolyl 4-hydroxylase inhibitor GSK360A decreases post-stroke brain injury and sensory, motor, and cognitive behavioral deficits

There is interest in pharmacologic preconditioning for end-organ protection by targeting the HIF system. This can be accomplished by inhibition of prolyl 4-hydroxylase (PHD). GSK360A is an orally active PHD inhibitor that has been previously shown to protect the failing heart. We hypothesized that PHD inhibition can also protect the brain from injuries and resulting behavioral deficits that can occur as a result of surgery. Thus, our goal was to investigate the effect of pre-stroke surgery brain protection using a verified GSK360A PHD inhibition paradigm on post-stroke surgery outcomes. Vehicle or an established protective dose (30 mg/kg, p.o.) of GSK360A was administered to male Sprague-Dawley rats. Initially, GSK360A pharmacokinetics and organ distribution were determined, and then PHD-HIF pharmacodynamic markers were measured (i.e., to validate the pharmacological effects of the GSK360A administration regimen). Results obtained using this validated PHD dose-regimen indicated significant improvement by GSK360A (30mg/kg); administered at 18 and 5 hours prior to transient middle cerebral artery occlusion (stroke). GSK360A exposure and plasma, kidney and brain HIF-PHD pharmacodynamics endpoints (e.g., erythropoietin; EPO and Vascular Endothelial Growth Factor; VEGF) were measured. GSK360A provided rapid exposure in plasma (7734 ng/ml), kidney (45–52% of plasma level) and brain (1–4% of plasma level), and increased kidney EPO mRNA (80-fold) and brain VEGF mRNA (2-fold). We also observed that GSK360A increased plasma EPO (300-fold) and VEGF (2-fold). Further assessments indicated that GSK360A reduced post-stroke surgery neurological deficits (47–64%), cognitive dysfunction (60–75%) and brain infarction (30%) 4 weeks later. Thus, PHD inhibition using GSK360A pretreatment produced long-term post-stroke brain protection and improved behavioral functioning. These data support PHD inhibition, specifically by GSK360A, as a potential strategy for pre-surgical use to reduce brain injury and functional decline due to surgery-related cerebral injury.

Capmul MCM/Solutol HS15-Based Microemulsion for Enhanced Oral Bioavailability of Rebamipide

Rebamipide (RBP) is a potent anti-ulcer and anti-oxidative agent, which is a BCS class IV drug with a low oral bioavailability of less than 10%. Thus, the systemic absorption of RBP into the blood circulation is an essential prerequisite for exerting its pharmacological activities after oral dosing. Herein, we report on microemulsion (ME) systems for the enhancement of oral RBP bioavailability. In this study, MEs consisting of Capmul MCM (oil), Solutol HS15 (surfactant), and ethanol (co-surfactant) were prepared by the construction of pseudo-ternary phase diagram. The RBP-loaded MEs had spherical nano-sized droplets with narrow size distribution and neutral zeta potential. Moreover, the prepared MEs significantly enhanced the dissolution and oral bioavailability of RBP with no discernible intestinal toxicity. These results suggest that the present ME system could be further developed as an alternative oral formulation for RBP.

Alterations in cellular pharmacokinetics and pharmacodynamics of elvitegravir in response to ethanol exposure in HIV-1 infected monocytic (U1) cells

Ethanol consumption is negatively associated with antiretroviral therapy (ART) adherence and general health in HIV positive individuals. Previously, we demonstrated ethanol-mediated alterations to metabolism of elvitegravir (EVG) in human liver microsomes. In the current study, we investigated ethanol influence on the pharmacokinetic and pharmacodynamic interactions of EVG in HIV infected monocytic (U1) cells. U1 cells were treated with 5 μM EVG, 2 μM Cobicistat (COBI), a booster drug, and 20 mM ethanol for up to 24 hours. EVG, HIV p24 levels, alterations in cytochrome P450 (CYP) 3A4, MRP1, and MDR1 protein expressions were measured. Presence of ethanol demonstrated a significant effect on the total exposures of both EVG and EVG in combination with COBI. Ethanol also increased the HIV replication despite the presence of drugs and this elevated HIV replication was reduced in the presence of MRP1 and MDR1 inhibitors. Consequently, a slight increase in EVG concentration was observed in the presence of MRP1 inhibitor but not with MDR1 inhibitor. Furthermore, CYP3A4, MRP1 and MDR1 protein levels were significantly induced in treatment groups which included ethanol compared to those with no treatment. In summary, these findings suggest that Ethanol reduces intra cellular EVG exposure by modifying drug metabolism and transporter protein expression. This study provides valuable evidence for further investigation of ethanol effects on the intracellular concentration of EVG in ex vivo or in vivo studies.

Design of a Biased Potent Small Molecule Inhibitor of the Bromodomain and PHD Finger-Containing (BRPF) Proteins Suitable for Cellular and in Vivo Studies

The BRPF (bromodomain and PHD finger-containing) family are scaffolding proteins important for the recruitment of histone acetyltransferases of the MYST family to chromatin. Evaluation of the BRPF family as a potential drug target is at an early stage although there is an emerging understanding of a role in acute myeloid leukemia (AML). We report the optimization of fragment hit 5b to 13-d as a biased, potent inhibitor of the BRD of the BRPFs with excellent selectivity over nonclass IV BRD proteins. Evaluation of 13-d in a panel of cancer cell lines showed a selective inhibition of proliferation of a subset of AML lines. Pharmacokinetic studies established that 13-d had properties compatible with oral dosing in mouse models of disease (Fpo 49%). We propose that NI-42 (13-d) is a new chemical probe for the BRPFs suitable for cellular and in vivo studies to explore the fundamental biology of these proteins.

Cystic fibrosis gene modifier SLC26A9 modulates airway response to CFTR-directed therapeutics

Cystic fibrosis is realizing the promise of personalized medicine. Recent advances in drug development that target the causal CFTR directly result in lung function improvement, but variability in response is demanding better prediction of outcomes to improve management decisions. The genetic modifier SLC26A9 contributes to disease severity in the CF pancreas and intestine at birth and here we assess its relationship with disease severity and therapeutic response in the airways. SLC26A9 association with lung disease was assessed in individuals from the Canadian and French CF Gene Modifier consortia with CFTR-gating mutations and in those homozygous for the common Phe508del mutation. Variability in response to a CFTR-directed therapy attributed to SLC26A9 genotype was assessed in Canadian patients with gating mutations. A primary airway model system determined if SLC26A9 shows modification of Phe508del CFTR function upon treatment with a CFTR corrector. In those with gating mutations that retain cell surface-localized CFTR we show that SLC26A9 modifies lung function while this is not the case in individuals homozygous for Phe508del where cell surface expression is lacking. Treatment response to ivacaftor, which aims to improve CFTR-channel opening probability in patients with gating mutations, shows substantial variability in response, 28% of which can be explained by rs7512462 in SLC26A9 (P = 0.0006). When homozygous Phe508del primary bronchial cells are treated to restore surface CFTR, SLC26A9 likewise modifies treatment response (P = 0.02). Our findings indicate that SLC26A9 airway modification requires CFTR at the cell surface, and that a common variant in SLC26A9 may predict response to CFTR-directed therapeutics.

Simultaneous quantification of tenofovir, emtricitabine, rilpivirine, elvitegravir and dolutegravir in mouse biological matrices by LC-MS/MS and its application to a pharmacokinetic study

Combination antiretroviral (cARV) treatment is more common in human immunodeficiency virus (HIV) infection. In many instances, treatment regimen includes two or more combination of drugs from six different classes. Some of the antiretroviral combination medications are under study at preclinical and clinical stages. A precise method is required to quantify the drug concentration in biological matrices to study pharmacokinetic behavior and tissue distribution profile in animals and/or humans. We have developed and validated a sensitive and precise liquid chromatography-tandem mass spectrometry method for simultaneous quantification of selected antiretroviral drugs, tenofovir (TNF), emtricitabine (FTC), rilpivirine (RPV), dolutegravir (DTG) and elvitegravir (EVG) in mouse biological matrices. This method involves a solid phase extraction, simple isocratic chromatographic separation using Restek Pinnacle DB BiPh column (50mm×2.1mm, 5μm) and mass spectrometric detection by an API 3200 Q Trap instrument. The total run time for each sample was 6min. The method was validated in the concentration range of 5-2000ng/mL for FTC, RPV, DTG, EVG and 10-4000ng/mL for TNF respectively with correlation coefficients (r(2)) higher than 0.9976. The results of intra and inter-run assay precision and accuracy were within acceptance limits for all the five analytes. This method was used to support the study of pharmacokinetics and tissue distribution profile of nanoformulated antiretroviral drugs in mice.

Drug Interactions with Cobicistat- or Ritonavir-Boosted Elvitegravir

Cobicistat and ritonavir are structurally distinct compounds that both potently inhibit cytochrome P450 (CYP) 3A, the metabolizing enzyme primarily responsible for the elimination of several antiretroviral medications, and, as such, are pharmacokinetic boosters for antiretroviral agents that require longer dosing intervals. Recently, cobicistat was approved for the treatment of HIV-1 infection in treatment-naive adults as a component of a single-tablet regimen consisting of cobicistat-boosted elvitegravir plus emtricitabine and tenofovir disoproxil fumarate. While studies have demonstrated that boosting with either cobicistat or ritonavir results in comparable plasma exposure of the target antiretroviral agent, a better understanding of drug-drug interactions between cobicistat- and ritonavir-boosted antiretrovirals and other medications will inform treatment decisions in HIV-infected patients. In connection with their distinct structural properties, COBI and RTV differ with respect to their drug-drug interaction profiles. Compared with ritonavir, cobicistat lacks induction potential and is a more specific inhibitor of 3A and therefore, has reduced effects on other CYP isoforms. To date, more studies have assessed ritonavir drug-drug interactions with other medications than have assessed cobicistat drug-drug interactions. The objective of this article is to review the drug-drug interactions when cobicistat- or ritonavir-boosted elvitegravir, cobicistat, or elvitegravir/cobicistat/emtricitabine/tenofovir are coadministered with antiretroviral therapies or drugs that are either substrates, inducers, or inhibitors of the CYP3A metabolic pathway, as well as with drugs that alter intra-gastric pH or are substrates of P-gp, in order to inform the proper use of elvitegravir/cobicistat/emtricitabine/tenofovir.

Adjunctive Brexpiprazole: A Review in Major Depressive Disorder

Brexpiprazole (Rexulti(®)) is a serotonin-dopamine activity modulator, with a unique receptor binding profile and low intrinsic D2 activity suggestive of a lower potential than aripiprazole to cause activation-like adverse effects, such as akathisia. The drug was recently approved by the US FDA for adjunctive therapy with antidepressant treatment (ADT) in patients with major depressive disorder (MDD). In two phase III trials, adjunctive oral brexpiprazole 2 or 3 mg once daily was more effective than monotherapy with ADT in improving depressive symptoms in adults with MDD who demonstrated an incomplete response to previous treatment with ADT. Adjunctive brexpiprazole was generally well tolerated in clinical trials, which included treatment periods of up to 52 weeks. Results of ongoing trials should help position the drug in the treatment of MDD. In the meantime, brexpiprazole provides a valid option for patients with persistent symptoms despite standard antidepressant therapy.

Rebamipide delivered by brushite cement enhances osteoblast and macrophage proliferation

Many of the bioactive agents capable of stimulating osseous regeneration, such as bone morphogenetic protein-2 (BMP-2) or prostaglandin E2 (PGE2), are limited by rapid degradation, a short bioactive half-life at the target site in vivo, or are prohibitively expensive to obtain in large quantities. Rebamipide, an amino acid modified hydroxylquinoline, can alter the expression of key mediators of bone anabolism, cyclo-oxygenase 2 (COX-2), BMP-2 and vascular endothelial growth factor (VEGF), in diverse cell types such as mucosal and endothelial cells or chondrocytes. The present study investigates whether Rebamipide enhances proliferation and differentiation of osteoblasts when delivered from brushite cement. The reactive oxygen species (ROS) quenching ability of Rebampide was tested in macrophages as a measure of bioactivity following drug release incubation times, up to 14 days. Rebamipide release from brushite occurs via non-fickian diffusion, with a rapid linear release of 9.70% ± 0.37% of drug per day for the first 5 days, and an average of 0.5%-1% per day thereafter for 30 days. Rebamipide slows the initial and final cement setting time by up to 3 and 1 minute, respectively, but does not significantly reduce the mechanical strength below 4% (weight percentage). Pre-osteoblast proliferation increases by 24% upon exposure to 0.4 uM Rebamipide, and by up to 73% when Rebamipide is delivered via brushite cement. Low doses of Rebamipide do not adversely affect peak alkaline phosphatase activity in differentiating pre-osteoblasts. Rebamipide weakly stimulates proliferation in macrophages at low concentrations (118 ± 7.4% at 1 uM), and quenches ROS by 40-60%. This is the first investigation of Rebamipide in osteoblasts.

Aripiprazole effects on self-administration and pharmacodynamics of intravenous cocaine and cigarette smoking in humans

Aripiprazole is a partial agonist at dopamine (D2) and serotonin (5-HT1a) receptors and 5-HT2 antagonist. Because cocaine affects dopamine and serotonin, this study assessed whether aripiprazole could diminish the reinforcing efficacy of cocaine. Secondary aims evaluated aripiprazole on ad lib cigarette smoking and with a novel 40-hr smoking abstinence procedure. Adults with regular cocaine and cigarette use completed this inpatient double blind, randomized, placebo-controlled mixed-design study. A placebo lead-in was followed by randomization to aripiprazole (0, 2 or 10 mg/day/p.o.; n = 7 completed/group). Three sets of test sessions, each consisting of 3 cocaine sample-choice (i.e., self-administration) sessions and 1 dose-response session, were conducted (once during the lead-in and twice after randomization). Sample sessions tested each cocaine dose (0, 20 and 40 mg/70 kg, i.v.) in random order; subjective, observer-rated and physiologic outcomes were collected. Later that day, participants chose between the morning's sample dose or descending amounts of money over 7 trials. In dose response sessions, all doses were given 1 hr apart in ascending order for pharmacodynamic and pharmacokinetic assessment. Two sets of smoking topography sessions were conducted during the lead-in and after randomization; 1 with and 1 without 40 hr of smoking abstinence. Number of ad lib cigarettes smoked during non-session days was collected. Cocaine produced prototypic effects, but aripiprazole did not significantly alter these effects or smoking outcomes. The smoking abstinence procedure reliably produced nicotine withdrawal and craving and increased smoking modestly. These data do not support further investigation of aripiprazole for cocaine or tobacco use disorder treatment.

Single- and multiple-dose pharmacokinetics of inhaled indacaterol in healthy Chinese volunteers

Indacaterol is an inhaled, ultra–long-acting β₂-agonist that provides 24-h bronchodilation with once-daily dosing in patients with chronic obstructive pulmonary disorder. This study evaluated the pharmacokinetics, safety, and tolerability of multiple daily inhaled doses of indacaterol 150 or 300 μg once daily in healthy Chinese volunteers. This was a single-center, randomized, double-blind, multiple-dose, parallel-group study, placebo-controlled trial including two doses of indacaterol: 150 and 300 μg. Serum indacaterol was quantified using high-performance liquid chromatography-mass spectrometry with a lower limit of quantification of 0.01 ng/mL. The pharmacokinetic parameters were analyzed using non-compartmental analysis and included C_max, T_max, and AUC_0–24h on Day 1 and AUC_0–24h,ss, C_max,ss, C_min,ss, C_av,ss, T_max,ss, T_1/2, T_1/2,acc, CL/F, V_z/F, and R_acc on Day 14 (after repeated once-daily doses). Safety analyses were recorded using physical examination, biochemical tests, and ECG. Indacaterol steady state was achieved after 12–14 days of daily dosing. The mean effective half-life of indacaterol (based on drug accumulation at steady state) was 33.9 and 35.8 h for 150 and 300 μg, respectively. Systemic exposure to indacaterol increased 1.27 and 1.34-fold between the 150- and 300-μg doses on Day 1 (first dose) and Day 14 (repeated dose), respectively. Indacaterol 150 and 300 μg were safe and well tolerated in these volunteers. The pharmacokinetics of multiple inhaled doses of indacaterol 150 and 300 μg (for 14 days) were consistent with moderate systemic accumulation at steady state after repeated once-daily inhalation in healthy Chinese volunteers.

Crystal structures of the fungal pathogen Aspergillus fumigatus protein farnesyltransferase complexed with substrates and inhibitors reveal features for antifungal drug design

Species of the fungal genus Aspergillus are significant human and agricultural pathogens that are often refractory to existing antifungal treatments. Protein farnesyltransferase (FTase), a critical enzyme in eukaryotes, is an attractive potential target for antifungal drug discovery. We report high-resolution structures of A. fumigatus FTase (AfFTase) in complex with substrates and inhibitors. Comparison of structures with farnesyldiphosphate (FPP) bound in the absence or presence of peptide substrate, corresponding to successive steps in ordered substrate binding, revealed that the second substrate-binding step is accompanied by motions of a loop in the catalytic site. Re-examination of other FTase structures showed that this motion is conserved. The substrate- and product-binding clefts in the AfFTase active site are wider than in human FTase (hFTase). Widening is a consequence of small shifts in the α-helices that comprise the majority of the FTase structure, which in turn arise from sequence variation in the hydrophobic core of the protein. These structural effects are key features that distinguish fungal FTases from hFTase. Their variation results in differences in steady-state enzyme kinetics and inhibitor interactions and presents opportunities for developing selective anti-fungal drugs by exploiting size differences in the active sites. We illustrate the latter by comparing the interaction of ED5 and Tipifarnib with hFTase and AfFTase. In AfFTase, the wider groove enables ED5 to bind in the presence of FPP, whereas in hFTase it binds only in the absence of substrate. Tipifarnib binds similarly to both enzymes but makes less extensive contacts in AfFTase with consequently weaker binding.

Role of aripiprazole in treating mood disorders

Atypical antipsychotics have been used to treat patients with schizophrenia for many years, but now there is increasing evidence of their utility in the treatment of mood disorders. In the past few years, several atypical agents have received regulatory approval for use in mania. The evidence shows that atypical antipsychotics are effective in the treatment of manic symptoms, either alone or in combination with traditional mood stabilizers, such as lithium and divalproex. Although emerging data indicate that atypical antipsychotics will be a promising addition to those therapies that are currently available for managing patients during the maintenance phase of bipolar illness, their potential in the long-term management of bipolar disorder remains to be fully explored. Aripiprazole is a recently released antipsychotic medication that differs from other atypical antipsychotic agents by its mode of action as a dopamine D2 partial agonist. It is administered orally and has a long half-life. Randomized studies have demonstrated the efficacy of aripiprazole compared with placebo in the treatment of acute relapse of schizophrenia and schizoaffective disorder, maintenance treatment of schizophrenia, treatment of acute mania, and prevention of manic relapse in patients who responded to the drug during a manic episode. Further studies are ongoing in bipolar and unipolar depression. Aripiprazole is generally well tolerated compared with other antipsychotic medications, although commonly reported side effects include extrapyramidal symptoms and motoric activation similar to akathisia. Further studies and postmarketing data will be helpful in providing additional information regarding the comparative safety, efficacy and tolerability of aripiprazole in the treatment of affective disorders.

Pharmacokinetic interactions between rebamipide and selected nonsteroidal anti-inflammatory drugs in rats

Nonsteroidal anti-inflammatory drugs (NSAIDs) cause gastrointestinal and renal side effects. Rebamipide is a mucoprotective agent that reduces gastrointenstinal side effects when administered concomitantly with NSAIDs. In this study, we investigated the pharmacokinetic drug interactions of rebamipide with two selected NSAIDs, celecoxib or diclofenac. Rats were randomly divided into five groups. Two groups received placebo and three groups were administered rebamipide (30 mg/kg) orally twice daily for two days. On day 3, the animals treated with placebo received celecoxib (40 mg/kg) or diclofenac (10mg/kg) and rats receiving rebamipide were administerd rebamipide followed by a single dose of placebo, celecoxib, or diclofenac. To investigate drug protein interactions, blank rat plasma was spiked with known concentrations of rebamipide, diclofenac plus rebamipide, or celecoxib plus rebamipide then dialyzed through a Rapid Equilibrium Dialysis device. AUC (139.70±24.97 μg h/mL), Cmax (42.99±2.98 μg/mL), and CLoral (0.08±0.02 L/h/kg) values of diclofenac in diclofenac plus rebamipide group altered when compared to those of diclofenac treated groups. Treatment with rebamipide showed no significant change in pharmacokinetic parameters of celecoxib treated rats. Cmax (7.80±1.22 μg/mL), AUC (56.46±7.30 μg h/mL), Vd/F (7.55±1.37 L/kg), and CLoral (0.58±0.09 L/h/kg) of rebamipide were significantly altered when diclofenac was co-administered with rebamipide. Pharmacokinetic parameters of rebamipide plus celecoxib group were not significantly different from those of rebamipide group. Plasma protein binding was not affected by concomitant administration of another drug. These results indicate alteration of pharmacokinetic parameters of both rebamipide and diclofenac when co-administered and cannot be explained by a variation in plasma protein binding.

Indacaterol: a comprehensive review

At present there is no cure for chronic obstructive pulmonary disease (COPD). However, some nonpharmacologic treatments, such as rehabilitation and lung volume reduction surgery, as well as pharmacologic intervention, can relieve some of the patient's symptoms and improve quality of life, while also reducing the rate of exacerbations and hospitalizations. There needs to be a paradigm shift away from the unjustified nihilistic approach to COPD towards considering it a preventable and treatable disease. After patients quit smoking and start to lead healthier lifestyles, long-acting bronchodilators, such as long-acting beta-adrenergic agents (LABA) and long-acting antimuscarinic agents (LAMA), are recommended as the cornerstone of treatment for COPD, either as monotherapy or in combination. COPD is characterized by a reduced maximum expiratory flow and slow forced emptying of the lungs, which progress over time and are not completely reversible. In this condition, gas gets trapped in the lungs and pulmonary hyperinflation occurs. LABA and LAMA improve airway patency and deflate the lungs. Indacaterol is the first once-daily LABA approved for treatment of COPD, and is administered by inhalation through the Breezhaler® device. The speed of bronchodilation is similar to that with salbutamol (ie, about five minutes) and longer (ie, 24 hours) than that with traditional LABA, with the same 12-hour effect as salmeterol and formoterol, both of which require twice-daily administration. This is why indacaterol has been called the "ultra-LABA". On the one hand, the fast onset of action provides immediate relief of symptoms, and on the other, its constant 24-hour bronchodilation provides "pharmacologic stenting" which facilitates lung emptying, thereby decreasing trapped gas and pulmonary hyperinflation. Once-daily administration of a fast and long-acting bronchodilator can improve patient adherence with therapy, which is known to be a major problem for many medical treatments. Dose-finding trials have shown that 75 μg is the minimum dose needed to achieve clinically important improvement. However, indacaterol 150 μg and 300 μg achieve an even greater improvement in lung function and patient-oriented outcomes. Further, these two doses of indacaterol significantly reduce pulmonary hyperinflation, thereby improving exercise tolerance and ability to perform day-to-day activities. It is more effective on lung volumes at the 300 μg dose than formoterol, and better than salmeterol and tiotropium at the 150 μg dose, at least in the acute setting. It is noteworthy that few studies document these results in patients with COPD and moderate airflow obstruction. These are exactly the kind of patients our research should be concentrating on, in view of the accelerated decay in forced expiratory volume in one second at this stage of the disease. Finally, all the relevant studies show that indacaterol is consistently well tolerated by patients with COPD at every stage, and that it has a high safety profile.

Symptom variability in COPD: a narrative review

Chronic obstructive pulmonary disease (COPD) has traditionally been considered an inexorably progressive disease, associated with a constant increase of symptoms that occur as the forced expiratory volume in 1 second (FEV1) worsens, only intermittently interrupted by exacerbations. However, this paradigm has been challenged in recent decades by the available evidence. Recent studies have pointed out that COPD-related symptoms are not consistently perceived by patients in the same way, showing not only seasonal variation, but also changes in symptom perception during a week or even within a single day. According to the available data, patients experience the biggest increase in respiratory symptoms during the first hours of the early morning, followed by the nighttime. This variation over time is of considerable importance, since it impacts on daily life activities and health-related quality of life, as measured by a recently developed ad hoc questionnaire. Additionally, recent clinical trials have suggested that the use of rapid-onset long-acting bronchodilators may have an impact on morning symptoms, despite their current use as maintenance treatment for a determined period. Although this hypothesis is to be validated in future long-term clinical trials comparing fast-onset versus slow-onset inhaled drugs in COPD, it may bring forward a new concept of long-term bronchodilator therapy. At the present time, the two available long-acting, fast-onset bronchodilators used in the treatment of COPD are formoterol and the recently marketed indacaterol. Newer drugs have also been shown to have a rapid onset of action in preclinical studies. Health care professionals caring for COPD patients should consider this variation in the perception of symptoms during their clinical interview as a potential new target in the long-term treatment plan.

Pharmacokinetics, Tolerability, and Safety of Aripiprazole following Multiple Oral Dosing in Normal Healthy Volunteers

Two 14-day, placebo-controlled, double-blind studies evaluated the fasting pharmacokinetics, safety, and tolerability of aripiprazole, a new antipsychotic, in healthy male subjects. In Study 1, 37 subjects were randomized to aripiprazole 5 mg, 10 mg, 15 mg, 20 mg, or placebo once daily. In Study 2, 11 subjects were randomized to aripiprazole, titrated from 10 to 30 mg/day, or placebo. Aripiprazole had linear pharmacokinetics over 5 to 30 mg/day, which were described by a two-compartment open model, with first-order absorption. In Study 1, mean elimination half-life ranged from 47 to 68 hours with aripiprazole, with apparent systemic clearance (CL/F) of approximately 3.45 L/h. In Study 2, mean elimination half-life was 59 hours (CL/F approximately 4.0 L/h). Adverse events were generally mild to moderate, were transient in nature, and commonly occurred within the first 3 days of dosing. Clinical laboratory assessments, electrocardiogram, electroencephalogram, and prolactin levels showed no clinically significant changes during the studies.

Pharmacokinetics of Aripiprazole and Concomitant Lithium and Valproate

The objective of this study was to assess the pharmacokinetics of the antipsychotic aripiprazole when coadministered with lithium or valproate. Two open-label, sequential treatment design studies were conducted in chronically institutionalized patients with schizophrenia or schizoaffective disorder requiring treatment with lithium (n = 12) or valproate (divalproex sodium) (n = 10). Patients received aripiprazole 30 mg/day on days 1 to 14 and aripiprazole with concomitant therapy on days 15 to 36. Lithium was titrated from 900 mg until serum concentrations reached 1.0 to 1.4 mEq/L for at least 5 days. Valproate was titrated to 50 to 125 mg/L. Coadministration with lithium increased mean Cmax and AUC values of aripiprazole by about 19% and 15%, respectively, whereas the apparent oral clearance decreased by 15%. There was no effect on the steady-state pharmacokinetics of the active metabolite of aripiprazole. Coadministration with valproate decreased the AUC and Cmax of aripiprazole by 24% and 26%, respectively, with minimal effects on the active metabolite. Therapeutic doses of lithium and divalproex had no clinically significant effects on the pharmacokinetics of aripiprazole in patients with schizophrenia or schizoaffective disorder.

Development of a simple LC-MS/MS method for determination of rebamipide in human plasma and its application to a bioequivalence study

The purpose of this study was to design a simple and rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for a rebamipide bioequivalence study in healthy Chinese male volunteers. In this method, sample pretreatment involved simple protein precipitation with venlafaxine as the internal standard. Analysis was achieved on a ZORBAX SB-C18 column with a concentration range of 6-1200 ng/mL. Rebamipide tablets from Yuanlijian (test, Hangzhou, China) and from Otsuka (reference, Hangzhou, China) were evaluated following a single 300 mg oral dose to 20 healthy volunteers. Bioequivalence was determined by calculating 90% confidence intervals (90% CI) for the ratio of Cmax, AUC(0-t) and AUC(0-infinity) values for the test and reference products, using logarithmic transformed data. The 90% confidence intervals for the ratio of Cmax (83.7-118.4%), AUC(0-t) (91.1-113.4%) and AUC(0-infinity) (90.6-113.2%) values for the test and reference products were within the interval (80.0-125.0% for AUC, and 70-143% for Cmax), proposed by State of Food and Drug Administration [SFDA, 2005. China]. It was concluded that the two rebamipide tablets were bioequivalent in their rate and extent of absorption and the method met the principle of quick and easy clinical analysis.

Pharmacology of HIV integrase inhibitors

PURPOSE OF REVIEW

The purpose of this study is to review recent and relevant pharmacology data for three HIV integrase inhibitors: raltegravir (marketed), dolutegravir, and elvitegravir (both in phase III drug development).

RECENT FINDINGS

Data from January 2011 to April 2012 were evaluated. These data better characterized integrase inhibitor pharmacokinetics, assessed dosing regimens, and investigated previously undescribed drug-drug interactions. Due to formulation challenges, raltegravir inter-patient and intra-patient pharmacokinetic variability is high. Twice-daily 400  mg dosing has been shown to be clinically superior to 800  mg once-daily dosing. A pediatric formulation of raltegravir with less variable pharmacokinetics and greater bioavailability was US Food and Drug Administration (US FDA)-approved in December 2011. Cobicistat-boosted elvitegravir, and the second-generation integrase inhibitor dolutegravir, have lower pharmacokinetic variability and are dosed once daily. Dolutegravir drug interactions are similar to raltegravir, whereas boosted elvitegravir participates in additional CYP3A-mediated interactions.

SUMMARY

Raltegravir's potent antiretroviral activity has resulted in widespread use in both treatment-naïve and experienced patients. Dolutegravir and cobicistat-boosted elvitegravir have some pharmacokinetic advantages. Pharmacokinetic data in special populations (pregnancy, pediatrics) to optimize dosing are still required.

Disposition and metabolism of 14C-dovitinib (TKI258), an inhibitor of FGFR and VEGFR, after oral administration in patients with advanced solid tumors

PURPOSE

This study investigated the metabolism and excretion of dovitinib (TKI258), a tyrosine kinase inhibitor that inhibits fibroblast, vascular endothelial, and platelet-derived growth factor receptors, in patients with advanced solid tumors.

METHODS

Four patients (cohort 1) received a single 500 mg oral dose of (14)C-dovitinib, followed by the collection of blood, urine, and feces for ≤10 days. Radioactivity concentrations were measured by liquid scintillation counting and plasma concentrations of dovitinib by liquid chromatography-tandem mass spectrometry. Both techniques were applied for metabolite profiling and identification. A continuous-dosing extension phase (nonlabeled dovitinib 400 mg daily) was conducted with the 3 patients from cohort 1 and 9 additional patients from cohort 2.

RESULTS

The majority of radioactivity was recovered in feces (mean 61 %; range 52-69 %), as compared with urine (mean 16 %; range 13-21 %). Only 6-19 % of the radioactivity was recovered in feces as unchanged dovitinib, suggesting high oral absorption. (14)C-dovitinib was eliminated predominantly via oxidative metabolism, with prominent primary biotransformations including hydroxylation on the fluorobenzyl ring and N-oxidation and carbon oxidation on the methylpiperazine moiety. Dovitinib was the most prominent radioactive component in plasma. The high apparent volume of distribution (2,160 L) may indicate that dovitinib distributes extensively to tissues. Adverse events were predominantly mild to moderate, and most common events included nausea, vomiting, constipation, diarrhea, and fatigue.

CONCLUSIONS

Dovitinib was well absorbed, extensively distributed, and eliminated mainly by oxidative metabolism, followed by excretion, predominantly in feces. The adverse events were as expected for this class of drug.

Hit-to-lead investigation of a series of novel combined dopamine D2 and muscarinic M1 receptor ligands with putative antipsychotic and pro-cognitive potential

We describe the discovery of a series of compounds based on 1-{3-[4-(2-oxo-2,3-dihydro-benzoimidazol-1-yl)-piperidin-1-yl]-propyl}-3,4-dihydro-1H-quinolin-2-one (3), showing combined D(2) receptor affinity and M(1) receptor agonism. Based on a strategy of controlling logP, we herein describe a hit-to-lead investigation with the aim of retaining the combined D(2)/M(1) profile, while removing the propensity of the compounds to inhibit the hERG channel, as well as at obtaining acceptable pharmacokinetic properties. Although a SAR was evident for all four parameters in question, it was not possible to separate hERG channel inhibition and D(2) receptor affinity by this effort; whilst it was feasible to obtain compounds with M(1) receptor agonism, acceptable clearance, and weak hERG inhibition.