Bioequivalence study of generic nirmatrelvir in healthy volunteers

Nirmatrelvir is an antiviral drug that, in combination with ritonavir, is an effective agent for the etiotropic therapy of patients with mild to moderate COVID-19. The aim of the study was to evaluate bioequivalence of the generic drug nirmatrelvir Arpaxel in combination with ritonavir and the original drug Paxlovid, which is a combination of nirmatrelvir/ritonavir, in a single dose administration to healthy volunteers.Materials and methods. This research was an open-label, randomized, two-period crossover bioequivalence study. It included 2 periods, in each of which the volunteers received either a test drug (nirmatrelvir at the dose of 300 mg) in combination with ritonavir (100 mg), or a reference drug (a combination of nirmatrelvir 300 mg and ritonavir 100 mg), given as a single dose. A wash-out period between each of the administrations was 7 days. The blood sampling to determine the concentration of nirmatrelvir was carried out in the range from 0 to 36 h in each of the study periods. A nirmatrelvir concentration was determined by a validated HPLC-MS/MS method with a lower quantitation limit of 10 ng/mL. Bioequivalence was assessed by comparing 90% confidence intervals (CIs) for the ratio of geometric means of AUC(0-36) and Cmax of the test drug and reference drugs with the established equivalence limits of 80.00-125.00%.Results. In the study were included 68 healthy volunteers, 67 participants of which were included in the bioequivalence population. The pharmacokinetic parameters of the drugs were comparable to each other. The 90% confidence interval for the ratio of the geometric mean of the maximum drug concentration in the blood plasma and the area under the pharmacokinetic curve << concentration-time >> from zero to the last blood draw within 36 hours of nirmatrelvir was 87.26-100.83 and 93.27-103.74%, which meets the criteria for assessing bioequivalence. The test drugs were well tolerated by the volunteers. The incidence of adverse events was similar for the test and reference drugs. No serious adverse events were recorded during the entire study.Conclusion. As a result of this study, bioequivalence of the test and reference drugs has been established.

Single-Dose Bioequivalence Study of Rivaroxaban-Containing Medicinal Products in Healthy Volunteers.

Therapeutically, new oral anticoagulants (NOACs) are considered to be non-inferior or superior to vitamin K antagonists (warfarin). NOACs are included in current guidelines for the treatment of various cardiovascular diseases. Rivaroxaban medicinal products have been shown to effectively fight thrombotic complications of the new coronavirus infection, COVID-19. The wide clinical use of rivaroxaban products motivates the development of generics. The aim of the study was to compare the pharmacokinetics and safety of rivaroxaban medicinal products in a single-dose bioequivalence study in healthy volunteers under fasting conditions. Material(s) and Method(s): the bioequivalence study compared single-dose oral administration of Rivaroxaban, 10 mg film-coated tablets (NovaMedica Innotech LLC, Russia), and the reference product Xarelto, 10 mg film-coated tablets (Bayer AG, Germany), in healthy volunteers under fasting conditions. The open, randomised, crossover trial included 46 healthy volunteers. Each of the medicinal products (the test product and the reference product) was administered once;blood samples were collected during the 48 h after the administration. The washout between the study periods lasted 7 days. Rivaroxaban was quantified in plasma samples of the volunteers by high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Result(s): no adverse events or serious adverse events were reported for the test and reference products during the study. The following pharmacokinetic parameters were obtained for Rivaroxaban and Xarelto, respectively: Cmax of 134.6 +/- 58.0 ng/mL and 139.9 +/- 49.3 ng/mL, AUC0-48 of 949.7 +/- 354.5 ngxh/mL and 967.6 +/- 319.9 ngxh/mL, AUC0- of 986.9 +/- 379.7 ngxh/mL and 1003.6 +/- 320.4 ngxh/mL, T1/2 of 8.2 +/- 3.2 h and 7.8 +/- 3.3 h. The 90% confidence intervals for the ratios of Cmax, AUC0-48, and AUC0- geometric means were 88.04-108.67%, 89.42-104.92% and 89.44-104.81%, respectively. Conclusion(s): the test product Rivaroxaban and the reference product Xarelto were found to have similar rivaroxaban pharmacokinetics and safety profiles. The study demonstrated bioequivalence of the medicinal products.Copyright © 2022 Obstetrics, Gynecology and Reproduction. All rights reserved.

Bioequivalence Study of Generic Molnupiravir in Healthy Volunteers

Molnupiravir is one of the drugs for the etiotropic therapy of a new coronavirus infection COVID-19. It has confirmed its clinical efficacy in the treatment of patients with mild and moderate COVID-19, including those who are at high risk of progressing to severe disease. The aim of the study was to evaluate bioequivalence of the generic drug molnupiravir ALARIO-TL and the original drug Lagevrio with a single oral administration in healthy volunteers. Materials and methods. This bioequivalence study was an open, randomized, two-period crossover study. In each of the two periods, volunteers received a single dose of the test drug, or reference drug molnupiravir, in the form of capsules at the dose of 200 mg. The washout period between the doses was 3 days. To determine pharmacokinetic (PK) parameters and bioequivalence, the concentration the concentration of N-hydrozycytidine (NHC), the main molnupiravir metabolit in the blood plasma of volunteers was evaluated. The blood plasma sampling was carried out in the range from 0 to 16 hours in each of the study periods. Bioequivalence was assessed by comparing 90% confidence intervals (CIs) for the ratio of geometric means of AUC(0-16) and Cmax of the test drug and reference drugs with the established equivalence limits of 80.00 - 125.00%. Results. A total of 28 healthy male volunteers were included in the study. According to the results of the statistical analysis, after the administration of the test and reference drugs, the 90% CIs for the ratio of the geometric means of AUC (0-16) and Cmax were 96.31% - 113.64% and 91.37% - 114.8%, respectively. These intervals fit within the established limits of 80.00-125.00%, which confirms the bioequivalence of the drugs. When comparing the frequency of the individual adverse events registration, no significant differences were found out after the administration of the test and reference drugs. Conclusion. Based on the results of this study, it can be concluded that the test and reference drugs of molnupiravir are bioequivalent. In addition, the data obtained indicate that the drugs have similar safety profiles.Copyright © 2022 Volgograd State Medical University, Pyatigorsk Medical and Pharmaceutical Institute. All rights reserved.

A leap towards enforcing medicines prescribing by generic names in low- and middle-income countries (LMICs): pitfalls, limitations, and recommendations for local drug regulatory agencies.

The Drug Regulatory Authority of Pakistan (DRAP) in response to the public outcry on increasing medicines prices in the country issued notifications to direct healthcare professionals to prescribe medicines with their generic names. Like DRAP, many regulators in the low- and middle-income countries (LMICs) are also inspiring from the west to legally enforce generic prescribing in a bid to reduce the out-of-pocket public expenditures. However, there are pitfalls in the LMICs drug regulatory framework, which if left unaddressed can severely jeopardise the foreseen benefits of medicines prescribing by generic names. This article critically appraises the impact of prescribing by generic names regulations in LMICs and highlights the key considerations that are vital to address before legally enforcing generic prescribing. The ethics, regulatory compliance, and good governance are the key to success; better generics for a better tomorrow.

Pharmacokinetic Comparison of Favipiravir Oral Solution and Tablet Formulations in Healthy Thai Volunteers.

This study compared the pharmacokinetics and safety of favipiravir oral solution with those of tablet formulations, which were agents repurposed to treat nonsevere coronavirus disease 2019 in Thailand. In an open-label, single-dose, randomized, crossover study, 24 healthy subjects under fasting conditions were randomly assigned to a single dose of 200 mg of favipiravir, either as an oral solution of 200 mg/15 mL (test product) or a tablet (reference product), separated by a 7-day washout period. Fifteen plasma samples were collected over 12 hours after drug administration. Plasma favipiravir levels were quantified using in-house developed ultra-high-performance liquid chromatography-tandem mass spectrometry. The test/reference geometric mean ratio along with 90%CI for the maximum plasma concentration, area under the concentration-time curve (AUC) to the time of the last quantifiable concentration, and AUC after single-dose administration, extrapolated to infinity were 115.3% (90%CI, 107.7%-123.3%), 100.4% (90%CI, 96.9%-104.0%), and 100.4% (90%CI, 96.8%-104.2%), respectively. These results were within the predefined acceptance criteria for bioequivalence (80.0%-125.0%). No adverse events were observed in either group. The oral solution formulation could offer the advantage of easier swallowing in broader patient groups.

Single-Dose Bioequivalence Study of Rivaroxaban-Containing Medicinal Products in Healthy Volunteers

Therapeutically, new oral anticoagulants (NOACs) are considered to be non-inferior or superior to vitamin K antagonists (warfarin). NOACs are included in current guidelines for the treatment of various cardiovascular diseases. Rivaroxaban medicinal products have been shown to effectively fight thrombotic complications of the new coronavirus infection, COVID-19. The wide clinical use of rivaroxaban products motivates the development of generics. The aim of the study was to compare the pharmacokinetics and safety of rivaroxaban medicinal products in a single-dose bioequivalence study in healthy volunteers under fasting conditions. Material(s) and Method(s): the bioequivalence study compared single-dose oral administration of Rivaroxaban, 10 mg film-coated tablets (NovaMedica Innotech LLC, Russia), and the reference product Xarelto, 10 mg film-coated tablets (Bayer AG, Germany), in healthy volunteers under fasting conditions. The open, randomised, crossover trial included 46 healthy volunteers. Each of the medicinal products (the test product and the reference product) was administered once;blood samples were collected during the 48 h after the administration. The washout between the study periods lasted 7 days. Rivaroxaban was quantified in plasma samples of the volunteers by high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Result(s): no adverse events or serious adverse events were reported for the test and reference products during the study. The following pharmacokinetic parameters were obtained for Rivaroxaban and Xarelto, respectively: Cmax of 134.6 +/- 58.0 ng/mL and 139.9 +/- 49.3 ng/mL, AUC0-48 of 949.7 +/- 354.5 ngxh/mL and 967.6 +/- 319.9 ngxh/mL, AUC0- of 986.9 +/- 379.7 ngxh/mL and 1003.6 +/- 320.4 ngxh/mL, T1/2 of 8.2 +/- 3.2 h and 7.8 +/- 3.3 h. The 90% confidence intervals for the ratios of Cmax, AUC0-48, and AUC0- geometric means were 88.04-108.67%, 89.42-104.92% and 89.44-104.81%, respectively. Conclusion(s): the test product Rivaroxaban and the reference product Xarelto were found to have similar rivaroxaban pharmacokinetics and safety profiles. The study demonstrated bioequivalence of the medicinal products. Copyright © 2022 Obstetrics, Gynecology and Reproduction. All rights reserved.

147th Annual Meeting American Neurological Association

The proceedings contain 417 papers. The topics discussed include: APOE is independently associated with the heterogeneity of cognitive decline rate in the normal aging-early Alzheimer's disease continuum;bioequivalence and safety comparison of once-weekly donepezil transdermal system with once-daily oral donepezil: results of a phase 1 trial in healthy volunteers;bleed type as a predictor of emotional and behavioral dyscontrol following intracerebral and subarachnoid hemorrhage;case series of manic symptoms following concussion;cognitive impairment in pulmonary hypertension;Creutzfeldt Jacob disease misdiagnosis, a diagnostic challenge and psychological burden: a case series;depressed neurocognitive function with comprehensive neuropsychiatric evaluation among long-haul COVID patients;evaluation of skin adhesion and local skin tolerability of once-weekly donepezil transdermal system: results of a phase 1 trial in healthy volunteers;determining etiologic diagnoses in rapidly progressive dementia: a clinical study;and frequency and distribution of transactive response DNA-binding protein 43 (TDP-43) pathology across the age spectrum in an elderly cohort with and without dementia.

Improved Performance Analysis for Cerebellar Ataxia disease Classification using AdaBoost

Artificial intelligence (AI) is the emerging field to diagnose and analyze chronic illnesses like Cerebellar Ataxia (CA), Spinocerebellar Ataxia (SCA), and Parkinson's disease. AI technologies such as machine learning and deep learning assist many doctors, diagnosis departments, and medical personnel in identifying and analyzing neurological disorders. Nowadays, AI used in most of the health care applications. Our research paper proffers an innovative approach to classify neurological disorders with various Machine learning algorithms. Existing research works experimented with machine learning algorithms like Support Vector machine and KNN, the performance of these algorithm is good, when the data is less and binary classified. In the proposed work, we have applied SVM, KNN, Decision tree and AdaBoost algorithms on the CA Data set. The performance of proposed methods exhibit improved accuracy when compared with the existing works. The results of the proposed work are tabulated for comparative analysis. We found that the AdaBoost algorithm shows the better classification result for Cerebellar Ataxia disease severity.

THE PROPER STUDY: A 48-WEEK ANALYSIS of A PAN-EU REAL-WORLD STUDY of SB5 BIOSIMILAR FOLLOWING TRANSITION from REFERENCE ADALIMUMAB in PATIENTS with RHEUMATOID ARTHRITIS, AXIAL SPONDYLOARTHRITIS or PSORIATIC ARTHRITIS

Background: SB5, a biosimilar to reference adalimumab (ADL), received EU marketing authorisation in 2017, based on pre-clinical and clinical phase I and III studies that demonstrated bioequivalence and comparable efficacy, safety and immunogenicity to ADL. Objectives: The real-world study 'PROPER' is designed to provide insights into outcomes of the transition from ADL to SB5 outside the randomised, controlled, clinical trial setting. Methods: Under an umbrella design, 1000 patients with immune-mediated infammatory disease were enrolled at centres in Belgium, Germany, Ireland, Italy, Spain and the UK, and followed for 48 weeks post-transition. Eligible patients with a diagnosis of rheumatoid arthritis (RA), axial spondyloarthritis (axSpA), psoriatic arthritis (PsA), ulcerative colitis or Crohn's disease had been transitioned to SB5 as part of routine treatment following a minimum of 16 weeks' treatment with ADL. Data were captured from patient charts retrospectively for 24 weeks prior to and prospectively and/or retrospectively up to 48 weeks after SB5 initiation. This analysis of the rheumatology cohort reports clinical characteristics, disease scores, persistence on SB5, clinical management and safety up to the closing date of November 30th, 2021. Results: Of the 496 patients included in this analysis, the majority were enrolled in UK (n=174), Germany (n=145) and Spain (n=73);Italy, Ireland and Belgium enrolled 45, 44 and 15 patients respectively. At study close, 487 patients had completed 48 weeks of follow-up;397 of those remained on SB5 throughout. Methotrexate was received as concomitant therapy by 37% of patients and 20% had received a biologic therapy prior to reference ADL. Most patients (89.3% of RA, 92.1% of axSpA, 97.3% of PsA) transitioned to SB5 at the same dose regimen received for ADL. Clinical characteristics, SB5 dose and fare are detailed in Table 1, disease scores in Figure 1. Fifteen patients each experienced one unrelated Serious Adverse Event (SAE): 2 in the axSpA cohort [tachycardia, intracranial haemorrhage];6 in the PsA cohort [myocardial infarct (2), breast carcinoma, COVID-19, gallbladder calculus, dyspnoea];7 in the RA cohort [facial numbness, depression, COVID-19, pneumonia, diverticulitis, parvovirus, coronary occlusion]. Tw o patients reported SAEs considered causally related to SB5: Herpes zoster and pneumonia (RA cohort), and ALS with worsening (PsA cohort). Conclusion: This analysis of a large, contemporary cohort of EU patients with established RA, axSpA or PsA shows treatment effectiveness maintained at 48 weeks after switching from ADL to SB5, with most patients continuing on SB5 Q2W throughout. Episodes of fare were uncommon, and the importance of patient-reported symptoms in recognition of fare is evident. No new safety signals were observed.

Bioequivalence study of a new formulation of paracetamol/ibuprofen during the COVID-19 pandemic

Objective: To determine the bioequivalence of two oral formulations of paracetamol 500 mg/ibuprofen 200 mg. Tolerability of both formulations of paracetamol/ ibuprofen were evaluated descriptively. Material and/or methods: Twenty-four healthy volunteers were enrolled at this random, single-dose, crossover, two-period design, open-label, bioequivalence study. After overnight fasting, two formulations (test and reference) of paracetamol/ibuprofen (paracetamol 500 mg/ ibuprofen 200-mg film coated tablets), were administered as a single dose on two treatment days separated by a 72 h (minimum) washout period. After dosing, blood samples were drawn for a period of 12 h. Pharmacokinetic parameters were determined from plasma concentrations for both formulations. The coronavirus disease 2019 (COVID-19) pandemic was declared a public health emergency of international concern by the WHO. Extraordinary safety measures were implemented at different levels that intended to preserve the clinical trial activities as far as possible, protecting the safety and preserving the traceability while no vaccine was available. These measures, locally, consisted of: information about the importance of the measures, PCR test for COVID-19 at the screening visit (if IgG serology was positive) and PCR test at every period of admission to Trials Unit, the subject came into the Unit only after a negative result. Results: The highest effort made to assure the safety of participants led to a regular development of the study, with only two cases excluded primarily and one excluded after the first dose administration. Regarding pharmacokinetics, the results found for Paracetamol: Ln (Cmax) ng/ml Ratio 92.83% (CI90: 83.73%-102.94%);Ln (AUClast) h∗ng/ml Ratio: 96.14% (CI90: 93.24%-99.13%);for Ibuprofen: Ln (Cmax) ng/ml Ratio: 93.78% (CI90: 85.43-102.96%), Ln (AUClast) h∗ng/ml Ratio: 96.06% (CI90: 93.75%-98.42%). No drug-related safety concerns appeared. Conclusions: The clinical development of the BE clinical trial was made available by the extraordinary safety measures adopted. The pharmacokinetics results comply with the regulatory requirements for bioequivalence. No significant findings concerning safety were found.

Rapid and sustained B-cell depletion with subcutaneous ofatumumab in relapsing multiple sclerosis: APLIOS, a randomized phase-2 study.

BACKGROUND: Ofatumumab, the first fully human anti-CD20 monoclonal antibody, is approved in several countries for relapsing multiple sclerosis (RMS). OBJECTIVE: To demonstrate the bioequivalence of ofatumumab administered by an autoinjector versus a pre-filled syringe (PFS) and to explore the effect of ofatumumab on B-cell depletion. METHODS: APLIOS (NCT03560739) is a 12-week, open-label, parallel-group, phase-2 study in patients with RMS receiving subcutaneous ofatumumab 20 mg every 4 weeks (q4w) (from Week 4, after initial doses on Days 1, 7, and 14). Patients were randomized 10:10:1:1 to autoinjector or PFS in the abdomen, or autoinjector or PFS in the thigh, respectively. Bioequivalence was determined by area under the curve (AUCτ) and maximum plasma concentration (Cmax) for Weeks 8-12. B-cell depletion and safety/tolerability were assessed. RESULTS: A total of 256 patients contributed to the bioequivalence analyses (autoinjector-abdomen, n = 128; PFS-abdomen, n = 128). Abdominal ofatumumab pharmacokinetic exposure was bioequivalent for autoinjector and PFS (geometric mean AUCτ, 487.7 vs 474.1 h × µg/mL (ratio 1.03); Cmax, 1.409 vs 1.409 µg/mL (ratio 1.00)). B-cell counts (median cells/µL) depleted rapidly in all groups from 214.0 (baseline) to 2.0 (Day 14). Ofatumumab was well tolerated. CONCLUSION: Ofatumumab 20 mg q4w self-administered subcutaneously via autoinjector is bioequivalent to PFS administration and provides rapid B-cell depletion.

A randomized pharmacokinetic/pharmacodynamic study comparing the bioequivalence of potential biosimilar candidate P044 with reference medicine in healthy volunteers.

BACKGROUND: P044 is a proposed biosimilar candidate of Teriparatide for reference medicine, Forsteo®. This study was designed to evaluate the Pharmacokinetic/Pharmacodynamic (PK/PD) bioequivalence between P044 and Forsteo®. METHODS: In this randomized, open-label, single-dose, crossover study, 66 healthy female subjects were randomized to receive P044 and Forsteo®. The primary PK endpoints of the study were the area under the concentration versus time from zero to infinity (AUC0-inf) and maximum plasma concentration (Cmax). Secondary endpoints included area under the concentration versus time from zero to the last quantifiable concentration (AUC0-last) and Cmax for PD parameter, additional PK parameters and safety. RESULTS: Sixty-six subjects were enrolled in the study and baseline demographics were similar between the two treatments. The two treatments presented similar PK/PD parameters and the 90% confidence interval for primary and secondary endpoints were within the bioequivalence acceptance range (80.00-125.00%) for all parameters. None of the subjects experienced serious adverse event, and all of the reported adverse events were mild and similar between two treatments. CONCLUSIONS: This study demonstrated the PK/PD similarity of P044 to reference medicine, Forsteo® and safety profiles were comparable between treatments. TRIAL REGISTRATION: EudraCT Number: 2019-004477-82.

Brand drug companies impeding generic drug company access to product samples: Estimated prevalence and impact on drug costs

Some brand drug companies have stymied attempts by generic drug companies to obtain samples of brand drugs needed to develop and gain regulatory approval for their generic products. This conduct, which has been reported in both the US and Canada, raises drug costs to drug plans and other payors and can lessen competition. The literature to date contains little empirical evidence on the prevalence of this conduct, the attendant effects on generic drug market launches and costs incurred by drug payors. This paper addresses these questions for Canada, using data on the drug development projects undertaken by the members of the Canadian Generic Pharmaceutical Association over the period 2015–2019. I found that about 16% of generic drug development projects were delayed due to originator firm efforts to impede access to samples of their drugs. The median generic drug launch delay (among affected drugs) attributable to the challenged conduct was 6 months. The additional costs to drug payors from the resulting delays in generic drug launches over the analysis period was in the order of $284 million, or $57 million annually. This study did not explore the additional generic drug development costs attributable to the challenged conduct.

Menthol-assisted homogenous liquid-liquid microextraction for HPLC/UV determination of favipiravir as an antiviral for COVID-19 in human plasma.

Favipiravir is a promising antiviral agent that has been recently approved for treatment of COVID-19 infection. In this study, a menthol-assisted homogenous liquid-liquid microextraction method has been developed for favipiravir determination in human plasma using HPLC/UV. The different factors that could affect the extraction efficiency were studied, including extractant type, extractant volume, menthol amount and vortex time. The optimum extraction efficiency was achieved using 300 µL of tetrahydrofuran, 30 mg of menthol and vortexing for 1 min before centrifuging the sample for 5 min at 3467g. Addition of menthol does not only induce phase separation, but also helps to form reverse micelles to facilitate extraction. The highly polar favipiravir molecules would be incorporated into the hydrophilic core of the formed reverse micelle to be extracted by the non-polar organic extractant. The method was validated according to the FDA bioanalytical method guidelines. The developed method was found linear in the concentration range of 0.1 to 100 µg/mL with a coefficient of determination of 0.9992. The method accuracy and precision were studied by calculating the recovery (%) and the relative standard deviation (%), respectively. The recovery (%) was in the range of 97.1-103.9%, while the RSD (%) values ranged between 2.03 and 8.15 %. The developed method was successfully applied in a bioequivalence study of Flupirava® 200 mg versus Avigan® 200 mg, after a single oral dose of favipiravir administered to healthy adult volunteers. The proposed method was simple, cheap, more eco-friendly and sufficiently sensitive for biomedical application.

Bioequivalence and food effect of a fixed-dose combination of macitentan and tadalafil: Adaptive design in the COVID-19 pandemic.

The COVID-19 pandemic has forced clinical studies to accommodate imposed limitations. In this study, the bioequivalence part could not be conducted as planned. Thus, the aim was to demonstrate bioequivalence, using an adaptive study design, of tadalafil in fixed-dose combination (FDC) tablets of macitentan/tadalafil with single macitentan and tadalafil (Canadian-sourced) tablets and assess the effect of food on FDC tablets in healthy subjects. This Phase 1, single-center, open-label, single-dose, two-part, two-period, randomized, crossover study enrolled 62 subjects. Tadalafil bioequivalence as part of FDC of macitentan/tadalafil (10/40 mg) with single-component tablets of macitentan (10 mg) and tadalafil (40 mg) was determined by pharmacokinetic (PK) assessment under fasted conditions. The effect of food on FDC was evaluated under fed and fasted conditions. Fasted 90% confidence intervals (CIs) for geometric mean ratios (GMRs) were within bioequivalence limits for tadalafil and macitentan. Fed and fasted 90% CIs for area under the curve (AUC) GMR were within bioequivalence limits. However, 90% CIs for maximum plasma concentration (Cmax ) GMR for macitentan and tadalafil were outside bioequivalence limits. One FDC-treated subject experienced a serious adverse event of transient ischemic attack (bioequivalence part). To address pandemic-imposed limitations, an adaptive study design was implemented to demonstrate that the FDC tablet was bioequivalent to the free combination of macitentan and tadalafil (Canadian-sourced). No clinically significant differences in PK were determined between fed and fasted conditions; the FDC formulation could be taken irrespective of meals. The FDC formulation under fasted and fed conditions was well tolerated with no clinically relevant differences in safety profiles between the treatment groups. NCT Number: NCT04235270.

A novel LC-MS/MS method for determination of the potential antiviral candidate favipiravir for the emergency treatment of SARS-CoV-2 virus in human plasma: Application to a bioequivalence study in Egyptian human volunteers.

A novel, fast and sensitive LC-MS/MS method was developed and validated for the bioanalysis of the antiviral agent favipiravir (FAV); a promising candidate for treatment of SARS-CoV-2 (COVID-19) in human plasma using pyrazinamide as an internal standard (IS). Simple protein precipitation was adopted for plasma sample preparation using methanol. Chromatographic separation was accomplished on Eclipse plus C18 column (50 × 4.6 mm, 3.5 µm) using a mobile phase composed of methanol-0.2 % acetic acid (20:80, v/v) pumped at a flow rate 0.6 mL/min in an isocratic elution mode. The API4500 triple quadrupole tandem mass spectrometer was operated with multiple-reaction monitoring (MRM) in negative electrospray ionization interface for FAV and positive for IS. The MRM function was used for quantification, with the transitions set at m/z 156.00→ 113.00 and m/z 124.80→ 81.00 for FAV and IS. The method was optimized and fully validated in accordance to US-FDA guidelines. Linearity was acquired over a concentration range of 100.0-20000.0 ng/mL by computing using weighted linear regression strategy (1/x2). The proposed method was effectively applied for the pharmacokinetic evaluation of FAV and to demonstrate the bioequivalence of a new FAV formulation (test) and reference product in healthy Egyptian human volunteers.