Re-recognizing bromhexine hydrochloride: pharmaceutical properties and its possible role in treating pediatric COVID-19

Application of Hydrophilic Polymers to the Preparation of Prolonged-Release Minitablets with Bromhexine Hydrochloride and Bisoprolol Fumarate

Minitablets have been extensively studied in recent years as a convenient pediatric form because they allow successful administration even in very young children. Their advantages include easy dose adjustment by multiplication of single units as well as the possibility of drug release modification by coating or forming matrix systems. The aim of this study was to demonstrate the possibility of the formulation of prolonged-release minitablets with bromhexine hydrochloride (BHX) and bisoprolol fumarate (BFM) dedicated to pediatric patients. Minitablets with 3 mm diameter and 15 mg mass, containing 1 mg of active substance in 1 unit, were prepared by direct compression with hydroxypropyl methylcellulose (HPMC) of different grades, methylcellulose, sodium alginate, or polyvinyl alcohol (PVA) as a sustained-release polymer. Different amounts of polymers and different compression forces were evaluated. Analysis of minitablets included their uniformity, hardness, and dissolution tests. The kinetics of drug substance release were analyzed with dedicated software. The prepared minitablets met the pharmacopeial requirements with respect to the uniformity of mass and content. The compressibility of BFM was significantly better than that of BHX, yet all minitablets had good mechanical properties. Dissolution studies showed a strong relationship between the type of polymer and its amount in the mass of a tablet and the dissolution rate. Prolonged release of up to 8 h was achieved when HPMC of 4000 cP viscosity was used in the amount of 30% to 80%. Sodium alginate in the amount of 50% was also effective in prolonging dissolution, but PVA was much less effective. Studies on the release kinetics showed that dissolution from prolonged-release minitablets with BHX fit the best to Hopfenberg or Hixson-Crowell models, while in the case of BFM, the best fit was found for Hopfenberg or Korsmeyer-Peppas models.

COVID-19 therapeutics: Clinical application of repurposed drugs and futuristic strategies for target-based drug discovery

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causes the complicated disease COVID-19. Clinicians are continuously facing huge problems in the treatment of patients, as COVID-19-specific drugs are not available, hence the principle of drug repurposing serves as a one-and-only hope. Globally, the repurposing of many drugs is underway; few of them are already approved by the regulatory bodies for their clinical use and most of them are in different phases of clinical trials. Here in this review, our main aim is to discuss in detail the up-to-date information on the target-based pharmacological classification of repurposed drugs, the potential mechanism of actions, and the current clinical trial status of various drugs which are under repurposing since early 2020. At last, we briefly proposed the probable pharmacological and therapeutic drug targets that may be preferred as a futuristic drug discovery approach in the development of effective medicines.

Current Insights and Molecular Docking Studies of the Drugs under Clinical Trial as RdRp Inhibitors in COVID-19 Treatment

Study Background & Objective: After the influenza pandemic (1918), COVID-19 was declared a Vth pandemic by the WHO in 2020. SARS-CoV-2 is an RNA-enveloped single-stranded virus. Based on the structure and life cycle, Protease (3CLpro), RdRp, ACE2, IL-6, and TMPRSS2 are the major targets for drug development against COVID-19. Pre-existing several drugs (FDA-approved) are used to inhibit the above targets in different diseases. In coronavirus treatment, these drugs are also in different clinical trial stages. Remdesivir (RdRp inhibitor) is the only FDA-approved medicine for coronavirus treatment. In the present study, by using the drug repurposing strategy, 70 preexisting clinical or under clinical trial molecules were used in scrutiny for RdRp inhibitor potent molecules in coronavirus treatment being surveyed via docking studies. Molecular simulation studies further confirmed the binding mechanism and stability of the most potent compounds.

MATERIAL AND METHODS

Docking studies were performed using the Maestro 12.9 module of Schrodinger software over 70 molecules with RdRp as the target and remdesivir as the standard drug and further confirmed by simulation studies.

RESULTS

The docking studies showed that many HIV protease inhibitors demonstrated remarkable binding interactions with the target RdRp. Protease inhibitors such as lopinavir and ritonavir are effective. Along with these, AT-527, ledipasvir, bicalutamide, and cobicistat showed improved docking scores. RMSD and RMSF were further analyzed for potent ledipasvir and ritonavir by simulation studies and were identified as potential candidates for corona disease.

CONCLUSION

The drug repurposing approach provides a new avenue in COVID-19 treatment.

Efficacy of Bromhexine versus Standard of Care in Reducing Viral Load in Patients with Mild-to-Moderate COVID-19 Disease Attended in Primary Care: A Randomized Open-Label Trial

A 28-day randomized open-label multicenter study was conducted to assess the efficacy of bromhexine plus standard of care (SOC) (n = 98) vs. SOC alone (n = 93) in 191 outpatients with mild-to-moderate COVID-19 in the primary health care setting. Bromhexine three daily doses of 10 mL (48 mg/day) were administered for seven days. The primary efficacy endpoint was the reduction of viral load estimated as the cycle thresholds (Ct) to detect ORF1ab, N Protein, and S Protein genes by RT-qPCR in saliva samples on day 4 as compared with baseline. Ct values of the three genes increased from baseline throughout days 4 to 14 (p < 0.001) but significant differences between the study groups were not found. Differences in the percentages of patients with low, medium, and high viral loads at 4, 7, and 14 days were not found either. In summary, treatment with bromhexine plus SCO was associated with a viral load reduction of ORF1ab, N Protein, and S Protein genes at day 4, which was not significantly different than similar viral load reductions observed with SOC alone. The present findings do not seem to favor the use of bromhexine as an antiviral in patients with COVID-19.

Pulmonary surfactant and COVID-19: A new synthesis

Chapter 1

COVID-19 pathogenesis poses paradoxes difficult to explain with traditional physiology. For instance, since type II pneumocytes are considered the primary cellular target of SARS-CoV-2; as these produce pulmonary surfactant (PS), the possibility that insufficient PS plays a role in COVID-19 pathogenesis has been raised. However, the opposite of predicted high alveolar surface tension is found in many early COVID-19 patients: paradoxically normal lung volumes and high compliance occur, with profound hypoxemia. That 'COVID anomaly' was quickly rationalised by invoking traditional vascular mechanisms-mainly because of surprisingly preserved alveolar surface in early hypoxemic cases. However, that quick rejection of alveolar damage only occurred because the actual mechanism of gas exchange has long been presumed to be non-problematic, due to diffusion through the alveolar surface. On the contrary, we provide physical chemical evidence that gas exchange occurs by an process of expansion and contraction of the three-dimensional structures of PS and its associated proteins. This view explains anomalous observations from the level of cryo-TEM to whole individuals. It encompasses results from premature infants to the deepest diving seals. Once understood, the COVID anomaly dissolves and is straightforwardly explained as covert viral damage to the 3D structure of PS, with direct treatment implications. As a natural experiment, the SARS-CoV-2 virus itself has helped us to simplify and clarify not only the nature of dyspnea and its relationship to pulmonary compliance, but also the fine detail of the PS including such features as water channels which had heretofore been entirely unexpected.

Chapter 2

For a long time, physical, colloid and surface chemistry have not intersected with physiology and cell biology as much as we might have hoped. The reasons are starting to become clear. The discipline of physical chemistry suffered from serious unrecognised omissions that rendered it ineffective. These foundational defects included omission of specific ion molecular forces and hydration effects. The discipline lacked a predictive theory of self-assembly of lipids and proteins. Worse, theory omitted any role for dissolved gases, O2, N2, CO2, and their existence as stable nanobubbles above physiological salt concentration. Recent developments have gone some way to explaining the foam-like lung surfactant structures and function. It delivers O2/N2 as nanobubbles, and efflux of CO2, and H2O nanobubbles at the alveolar surface. Knowledge of pulmonary surfactant structure allows an explanation of the mechanism of corona virus entry, and differences in infectivity of different variants. CO2 nanobubbles, resulting from metabolism passing through the molecular frit provided by the glycocalyx of venous tissue, forms the previously unexplained foam which is the endothelial surface layer. CO2 nanobubbles turn out to be lethal to viruses, providing a plausible explanation for the origin of 'Long COVID'. Circulating nanobubbles, stable above physiological 0.17 M salt drive various enzyme-like activities and chemical reactions. Awareness of the microstructure of Pulmonary Surfactant and that nanobubbles of (O2/N2) and CO2 are integral to respiratory and circulatory physiology provides new insights to the COVID-19 and other pathogen activity.

Host Serine Proteases: A Potential Targeted Therapy for COVID-19 and Influenza

The ongoing pandemic illustrates limited therapeutic options for controlling SARS-CoV-2 infections, calling a need for additional therapeutic targets. The viral spike S glycoprotein binds to the human receptor angiotensin-converting enzyme 2 (ACE2) and then is activated by the host proteases. Based on the accessibility of the cellular proteases needed for SARS-S activation, SARS-CoV-2 entrance and activation can be mediated by endosomal (such as cathepsin L) and non-endosomal pathways. Evidence indicates that in the non-endosomal pathway, the viral S protein is cleaved by the furin enzyme in infected host cells. To help the virus enter efficiently, the S protein is further activated by the serine protease 2 (TMPRSS2), provided that the S has been cleaved by furin previously. In this review, important roles for host proteases within host cells will be outlined in SARS-CoV-2 infection and antiviral therapeutic strategies will be highlighted. Although there are at least five highly effective vaccines at this time, the appearance of the new viral mutations demands the development of therapeutic agents. Targeted inhibition of host proteases can be used as a therapeutic approach for viral infection.

Potential Prophylactic Treatments for COVID-19

The World Health Organization declared the SARS-CoV-2 outbreak a Public Health Emergency of International Concern at the end of January 2020 and a pandemic two months later. The virus primarily spreads between humans via respiratory droplets, and is the causative agent of Coronavirus Disease 2019 (COVID-19), which can vary in severity, from asymptomatic or mild disease (the vast majority of the cases) to respiratory failure, multi-organ failure, and death. Recently, several vaccines were approved for emergency use against SARS-CoV-2. However, their worldwide availability is acutely limited, and therefore, SARS-CoV-2 is still expected to cause significant morbidity and mortality in the upcoming year. Hence, additional countermeasures are needed, particularly pharmaceutical drugs that are widely accessible, safe, scalable, and affordable. In this comprehensive review, we target the prophylactic arena, focusing on small-molecule candidates. In order to consolidate a potential list of such medications, which were categorized as either antivirals, repurposed drugs, or miscellaneous, a thorough screening for relevant clinical trials was conducted. A brief molecular and/or clinical background is provided for each potential drug, rationalizing its prophylactic use as an antiviral or inflammatory modulator. Drug safety profiles are discussed, and current medical indications and research status regarding their relevance to COVID-19 are shortly reviewed. In the near future, a significant body of information regarding the effectiveness of drugs being clinically studied for COVID-19 is expected to accumulate, in addition to information regarding the efficacy of prophylactic treatments.

Drug Repurposing Approach, Potential Drugs, and Novel Drug Targets for COVID-19 Treatment

Novel coronavirus first appeared in Wuhan, China, in December 2019, and it speedily expanded globally. Some medications which are used to treat other diseases seem to be effective in treating COVID-19 even without explicit support. The existing drugs that are summarized in this review primarily focused on therapeutic agents that possessed activity against other RNA viruses such as MERS-CoV and SARS-CoV. Drug repurposing or repositioning is a promising field in drug discovery that identifies new therapeutic opportunities for existing drugs such as corticosteroids, RNA-dependent RNA polymerase inhibitors, interferons, protease inhibitors, ivermectin, melatonin, teicoplanin, and some others. A search for new drug/drug targets is underway. Thus, blocking coronavirus structural protein, targeting viral enzyme, dipeptidyl peptidase 4, and membrane fusion blocker (angiotensin-converting enzyme 2 and CD147 inhibitor) are major sites based on molecular targets for the management of COVID-19 infection. The possible impact of biologics for the management of COVID19 is promising and includes a wide variety of options such as cytokines, nucleic acid-based therapies targeting virus gene expression, bioengineered and vectored antibodies, and various types of vaccines. This review demonstrates that the available data are not sufficient to suggest any treatment for the eradication of COVID-19 to be used at the clinical level. This article aims to review the roles of existing drugs and drug targets for COVID-19 treatment.

Eco-friendly UPLC-MS/MS analysis of possible add-on therapy for COVID-19 in human plasma: Insights of greenness assessment

Facing the pandemic COVID-19 is of highest priority for all researchers nowadays. Recent statistics indicate that the majority of the cases are home-treated. Two drugs of interest, Guaifenesin and Bromohexine HCl, are among the add-on therapy for treatment of COVID-19 mild cases, which has raised the need for their simultaneous determination. The analysis of the two drugs of interest was described using ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) in plasma of healthy human volunteers using tetryzoline HCl as an internal standard (IS) after liquid-liquid extraction. The applied chromatographic conditions were Kinetex C₁₈ (100 Å, 2.6 µm X 50 mm X 4.6 mm) column and a mixture of methanol: water (95: 5, v/v) as a mobile phase at flow rate 1 mL/min. The positive ionization mode was used for detecting the ions, by observing the pairs of transition m/z 199 < 125 for GUF, m/z 377 < 114 for BRM and m/z 201 < 131 for IS. The linearity range was from 50 to 1500 ng/mL for GUF and 0.5-50 µg/mL for BRM. Limit of detection (LOD) was found to be 35.16 and 0.43 ng/ml for GUF and BRM, respectively. The method was validated according to FDA guidance. The proposed method was assessed to be more eco-friendly versus the reported method using the greenness assessment tools: National Environmental Methods Index (NEMI), Assessment of Green Profile (AGP), Green Analytical Procedure Index (GAPI) and Eco-Scale. The proposed method was applied for the application of a pilot pharmacokinetic study.