Improving the Dissolution Rate and the Bioavailability of Favipiravir by Solid Dispersion with Curcumin

Favipiravir is an anti-viral agent that inhibits RNA-dependent RNA polymerase of several RNA viruses and is approved for the treatment of influenza in Japan. It has a role as an antiviral drug, an anti-coronaviral (COVID-19) agent but the poor solubility of the favipiravir in the aqueous media of the human body cause a reduction in the effectiveness and bioavailability. In the current work, the favipiravir was formulated for the first time as solid dispersed system with curcumin to improve dissolution property and antiviral activity during treatment of Covid-19. Binary and ternary mix of favipiravir and curcumin with/without soluplus were prepared and characterized by Differential Scanning Calorimetry (DSC), Powder X-ray Diffractometry (PXRD) and Fourier Transform Infrared Spec-troscopy (FTIR) and subjected to the dissolution test by apparatus I according to the European Pharma-copeia. The antiviral activity was measured by its cytotoxicity against A549-hACE2 cells. The results re-vealed that there was a reduction in the crystallinity of both binary and ternary mixtures with an en-hancement of the dissolution in comparison with the pure drug which accompanied by an improvement in the antiviral activity which is promising results that need further .Copyright © 2023, Colegio de Farmaceuticos de la Provincia de Buenos Aires. All rights reserved.

Modeling DNA Oligonucleotide Binding to DNA-mimetic Stem-Loop 1 of the SARS-CoV-2 RNA

SARS-CoV-2 is a positive-sense RNA virus that contains open reading frame 1ab (ORF1ab) to produce 16 nonstructural proteins (nsps). Five stem-loops (SL) are found in the 5' UTR of the RNA that are involved in myriad viral functions and are labeled SL1 through SL5. SL1 is crucial to viral replication. Upon viral infection, nsp1 binds the ribosomal 40S subunit to inhibit all host mRNA translation. Upon SL1 binding to nsp1, viral mRNA can be processed by the ribosome, allowing viral proteins to be produced. In this study, we are examining small DNA oligonucleotides that bind to SL1-mimetic DNA in order to block SL1-nsp1 interactions. We designed a DNA analog of the SL1 hairpin and two small DNA oligonucleotides that are complementary to either the helical stem or the loop region of SL1. The binding of these oligonucleotides to the SL1 hairpin should allow the formation of either an alternate duplex or a triplex structure. Isothermal titration calorimetry (ITC) and circular dichroism (CD) techniques were performed in 1 MKCl and 10 mM MgCl2 at two different pH (5.5 and 7.0) to examine structural and thermodynamics of binding. ITC of the two oligonucleotides showed modest binding. Results from DNA binding experiments, thermal denaturation, and CD show the hairpin structure is thermodynamically more favored and mostly remains intact under the conditions examined.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.

Indirect Calorimetry Critical in Identifying Early Hypometabolism and Late-Stage Hypermetabolism in Post-surgical Patients

Background: Indirect calorimetry (IC) is the gold-standard procedure for measuring resting energy expenditure (REE) in hospitalized patients. Predictive energy equations commonly use static variables and rarely account for changes in REE throughout hospitalization. We hypothesize that predictive equations are typically inaccurate in surgical intensive care unit (ICU) patients. More specifically, we hypothesize that predictive equations often overpredict measured resting energy expenditure (mREE) in early-stage critical illness and underpredict needs later in surgical ICU stay, leading to over-/under-feeding and associated complications. Method(s): This prospective observational trial enrolled surgical ICU patients who underwent emergent or urgent operations for abdominal trauma, perforated viscus, or ischemic bowel within 72 hours of their surgical procedure. Metabolic assessments were performed using the COSMED Q-NRG + Metabolic Monitor ventilator, mask, and canopy at regular intervals during and post ICU admission until hospital discharge. Measurements were categorized by post-surgical intervention ICU admission days 0-3, 4-7, 8-14, 15-21, and 22-28. Patients with multiple measurements taken during the same time interval were averaged. mREE reported in calories (kcal) per kilogram (kg) of admission body weight per day were compared in obese (BMI > 30 kg/m2) and non-obese (BMI < 30 kg/m2) subgroups. Compared to IC, the Mifflin St Jeor (MSJ) equation determined predicted REE using ICU admission anthropometrics. Data are reported as mean+/-standard error of the mean (SEM) and median (interquartile range), and a two-sided p-value of <0.05 was determined significant. Result(s): In total, 18 surgical ICU patients who contributed 47 IC measurements were included in the analysis (Table 1). Most measures were obtained within the first 7 days of post-surgical ICU admission (72%). mREE peaked between days 8-14 in obese and non-obese subgroups (20.6 vs 28.5 kcal/kg;p = 0.02) and was lowest during 0-3 days of post-surgical ICU admission in both groups. Across all 5-time intervals, average kcal/ kg ranged from 14.7-20.6 among obese patients and from 20.1-28.5 in non-obese counterparts (Table 2). Non-obese patients had higher mREE per kg of body weight than obese patients at all time points (Figure 1). MSJ over-predicted mREE during the first 7 days post ICU admission in non-obese patients and within the first 3 days in obese patients and underpredicted mREE in both groups thereafter. Conclusion(s): Equations such as MSJ over- and under-predict mREE in post-operative surgical ICU patients depending on the days elapsed since post-surgical ICU admission. ASPEN's current guideline recommendation of 12-25 kcal/kg may also underfeed post-surgical populations while 25 kcal/kg may not support hypermetabolism among non-obese patients seen in week 2 following post-surgical ICU admission. Alternatively, MSJ multiplied by a 1.2 activity factor may account for hypermetabolism during this time. Notably, non-obese patients experienced greater hypermetabolism than obese patients during week 2 which is consistent with our previously published data in mechanically ventilated COVID- 19 patients. Additionally, the striking dichotomy between the mREE of obese and non-obese patients at all post-surgical time points should be considered in the clinical care of patients. Ultimately, IC remains the gold-standard means of measuring REE and is a critical tool to capture the dynamic nature of energy requirements in post-surgical populations as weight-based and predictive equations continually fall short. (Table Presented).

Determining the Effect of KmtR Mutants, E101Q, H102Q, and H111Q on the Metal Binding Affinities

Mycobacterium tuberculosis is the second leading infectious killer after COVID-19. The bacteria utilizes several metal transport systems to help it survive in the host.With an increase in the number of multiresistant, extensively resistant and totally drug-resistant strains, the development of new therapeutic strategies that target other essential pathways in the bacteria is critical. The bacteria contain several metal transport systems which are necessary for its survival. Additionally, the bacteria has two metalloregulators that are associated with nickel and cobalt export, NmtR and KmtR. The focus of this research is on KmtR, which represses the expression of the genes, cdf (which encodes the export protein) and kmtR. The goal of our research is to identify the residues that are responsible for binding the cognate metals, nickel and cobalt, as well as the noncognate metal, zinc, to KmtR. Mutagenesis studies coupled with metal binding experiments will be used to determine how KmtR binds these metals. The E101Q, H102Q, and H111Q mutants, among others, have been made, expressed, and purified in our lab. Data obtained from Isothermal Titration Calorimetry determined that all three mutant proteins bind cobalt with nanomolar affinities and the H111Q mutant KmtR proteins binds cobalt an order of magnitude weaker than the other two mutant proteins. Research reported as supported fully by the RI Institutional Development Award (IDeA) Network for Biomedical Research Excellence (RI-INBRE) from the National Institute of General Medical Sciences of the National Institutes of Health under grant #P20GM103430.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.

Development of Aptasensor for the Diagnosis of Covid-19

Objectives: The objective is to develop a low-cost, practical, portable aptasensor platform for the diagnosis of COVID-19. Materials -Methods: Amino-terminated aptamers to be used for the design of an aptasensor were synthesized by SELEX method, and interaction of aptamers with SARS-CoV-2 S1 protein was investigated by isothermal titration calorimetry (ITC). Gold electrodes were used to design the biosensor platform. After the electrode surface was functionalized with cysteamine, the amino-terminated aptamer was conjugated to the surface via glutaraldehyde crosslinker. Then, the surface characterization and analytical parameters of the designed sensing platform were determined by adding commercial S1 proteins on the surface using differential pulse voltammetry (DPV), cyclic voltammetry (CV) and impedance spectroscopy (EIS). To evaluate the working performance of the system, S1 proteins were added to the synthetic serum samples using the standard addition method and the measurements were repeated. Result(s): Surface characterization of the platform designed with EIS and CV measurements was performed and it was found that the modification was successfully performed. In addition, DPV results and analytical parameters of the platform (calibration plot, limit of detection(LOD) , repeatability, coefficient of variation) were determined and the working performance of system was evaluated. Moreover, working performance of the biosensor in real samples and its specificity for COVID -19 were determined by experiments with synthetic serum and influenza A and B proteins. Conclusion(s): According the results, the system has potential to be used for the detection of COVID -19, and also it can be rapidly adapted in different pandemic situations that may occur in the future.

Towards New Antimicrobials - Targeting Bacterial Response Regulators

Purpose of Study: Antibiotic resistance remains one of the largest healthcare and public health challenges. Several studies have documented that the spread of antibiotic resistant bacteria in nosocomial settings has been exacerbated worldwide due to increased rates of hospitalization and intubation in the wake of the COVID-19 pandemic. One way to address antibiotic resistance is to identify novel compounds that inhibit essential microbial processes. Two-component regulatory systems are important mediators of signal transduction that allow bacteria to communicate with and respond to changes in their environment. The WalRK system is a two-component system that is conserved and essential for viability in many Gram-positive human pathogens. We hypothesize that a ligand that specifically binds with the DNA-interaction surface of the WalR protein can lead to cell death and can serve as a lead compound for future drug development efforts. Methods Used: We describe the development process of an assay to identify WalR binding compounds. In silico molecular dynamics docking approaches were utilized to identify potential WalR binding compounds from virtual compound libraries. To assess their WalR-binding capacity in vitro, overexpression strains for several WalR recombinant constructs were engineered and protein constructs were purified to homogenicity. Isothermal titration calorimetry (ITC) is a technique that measures heat release or absorption when two molecules interact. A MicroCal PEAQ ITC instrument was utilized to develop a WalR-binding assay. Summary of Results: WalR is a two-domain protein featuring a regulatory and a DNA-binding domain. Two constructs, a truncated DNA-binding domain and a full-length protein construct proved soluble, and pure quantities necessary to conduct ITC measurements could be successfully obtained (12 mg full-length protein and 23 mg truncated protein). These proteins were amenable to ITC experiments. We found that experiments were best run with at least a two-fold increase of ligand concentration to protein concentration supplied in identical buffer conditions over nineteen injections. We are currently assessing the binding affinities of our in silico hit compounds. Conclusion(s): Our results show that ITC enables the detailed, rapid, and reproducible characterization of the binding relationship between the DNA-binding domain of the WalR protein and any potential ligands. The protocol discussed herein will enable further drug discovery studies on the WalR response regulator protein to identify and characterize inhibitors, providing insight towards the development of novel antimicrobial compound.

Swine nutrition and environment

Evidently, pathogens and swine herd health are regarded as the top risk factors that can potentially disrupt normal pork production. Since the last edition of the Sustainable Swine Nutrition edited by Chiba, unprecedented global COVID-19 pandemic challenges and disruptive cell-based new meat production technologies have emerged, which need to be touched on in the context. COVID-19 has been causing enormous damages in losses of a large number of human lives and disruption of global social and economic activities, being regarded as the most severe pandemic occurred within the past century ever since the 1918 Influenza Pandemic. Carbon is fundamental in metabolic energy-contributing ingredients, namely starch, proteins, oils and fats, and nonstarch polysaccharides, and is an essential component measured during indirect calorimetry experimentation. Gut microbiota contributes to digestion and degradation of dietary carbon nutrients in pigs. © 2023 John Wiley & Sons Ltd.

How do guideline recommended energy targets compare with measured energy expenditure in critically ill adults with obesity: A systematic literature review.

BACKGROUND: Critically ill patients with obesity have unique and complex nutritional needs, with clinical practice guidelines conflicting regarding recommended energy targets. The aim of this systematic review was to 1) describe measured resting energy expenditure (mREE) reported in the literature and; 2) compare mREE to predicted energy targets using the European (ESPEN) and American (ASPEN) guideline recommendations when indirect calorimetry is not available in critically ill patients with obesity. METHODS: The protocol was registered apriori and literature was searched until 17th March, 2022. Original studies were included if they reported mREE using indirect calorimetry in critically ill patients with obesity (BMI≥30 kg/m2). Group-level mREE data was reported as per the primary publication using mean ± standard deviation or median [interquartile range]. Where individual patient data was available, Bland-Altman analysis was used to assess mean bias (95% limits of agreement) between guideline recommendations and mREE targets (i.e. ASPEN for BMI 30-50, 11-14 kcal/kg actual weight compared to 70% mREE and ESPEN 20-25 kcal/kg adjusted weight compared to 100% mREE). Accuracy was assessed by the percentage (%) of estimates within ±10% of mREE targets. RESULTS: After searching 8019 articles, 24 studies were included. mREE ranged from 1607 ± 385 to 2919 [2318-3362]kcal and 12-32kcal/actual body weight. For the ASPEN recommendations of 11-14 kcal/kg, a mean bias of -18% (-50% to +13%) and 4% (-36% to +44%) was observed, respectively (n = 104). For the ESPEN recommendations 20-25 kcal/kg, a bias of -22% (-51% to +7%) and -4% (-43% to +34%), was observed, respectively (n = 114). The guideline recommendations were able to accurately predict mREE targets on 30%-39% occasions (11-14 kcal/kg actual) and 15%-45% occasions (20-25 kcal/kg adjusted), for ASPEN and ESPEN recommendations, respectively. CONCLUSIONS: Measured energy expenditure in critically ill patients with obesity is variable. Energy targets generated using predictive equations recommended in both the ASPEN and ESPEN clinical guidelines have poor agreement with mREE and are frequently not able to accurately predict within ±10% of mREE, most commonly underestimating energy needs.

Validation of Oura ring energy expenditure and steps in laboratory and free-living.

BACKGROUND: Commercial activity trackers are increasingly used in research and compared with research-based accelerometers are often less intrusive, cheaper, with improved storage and battery capacity, although typically less validated. The present study aimed to determine the validity of Oura Ring step-count and energy expenditure (EE) in both laboratory and free-living. METHODS: Oura Ring EE was compared against indirect calorimetry in the laboratory, followed by a 14-day free-living study with 32 participants wearing an Oura Ring and reference monitors (three accelerometers positioned at hip, thigh, and wrist, and pedometer) to evaluate Oura EE variables and step count. RESULTS: Strong correlations were shown for Oura versus indirect calorimetry in the laboratory (r = 0.93), and versus reference monitors for all variables in free-living (r ≥ 0.76). Significant (p < 0.05) mean differences for Oura versus reference methods were found for laboratory measured sitting (- 0.12 ± 0.28 MET), standing (- 0.27 ± 0.33 MET), fast walk (- 0.82 ± 1.92 MET) and very fast run (- 3.49 ± 3.94 MET), and for free-living step-count (2124 ± 4256 steps) and EE variables (MET: - 0.34-0.26; TEE: 362-494 kcal; AEE: - 487-259 kcal). In the laboratory, Oura tended to underestimate EE with increasing discrepancy as intensity increased. The combined activities and slow running in the laboratory, and all MET placements, TEE hip and wrist, and step count in free-living had acceptable measurement errors (< 10% MAPE), whereas the remaining free-living variables showed close to (≤13.2%) acceptable limits. CONCLUSION: This is the first study investigating the validity of Oura Ring EE against gold standard methods. Oura successfully identified major changes between activities and/or intensities but was less responsive to detailed deviations within activities. In free-living, Oura step-count and EE variables tightly correlated with reference monitors, though with systemic over- or underestimations indicating somewhat low intra-individual validity of the ring versus the reference monitors. However, the correlations between the devices were high, suggesting that the Oura can detect differences at group-level for active and total energy expenditure, as well as step count.

Development of thermosensitive hydrogel of Amphotericin-B and Lactoferrin combination-loaded PLGA-PEG-PEI nanoparticles for potential eradication of ocular fungal infections: In-vitro, ex-vivo and in-vivo studies.

The most prevalent conditions among ocular surgery and COVID-19 patients are fungal eye infections, which may cause inflammation and dry eye, and may cause ocular morbidity. Amphotericin-B eye drops are commonly used in the treatment of ocular fungal infections. Lactoferrin is an iron-binding glycoprotein with broad-spectrum antimicrobial activity and is used for the treatment of dry eye, conjunctivitis, and ocular inflammation. However, poor aqueous stability and excessive nasolacrimal duct draining impede these agens' efficiency. The aim of this study was to examine the effect of Amphotericin-B, as an antifungal against Candida albicans, Fusarium, and Aspergillus flavus, and Lactoferrin, as an anti-inflammatory and anti-dry eye, when co-loaded in triblock polymers PLGA-PEG-PEI nanoparticles embedded in P188-P407 ophthalmic thermosensitive gel. The nanoparticles were prepared by a double emulsion solvent evaporation method. The optimized formula showed particle size (177.0 ± 0.3 nm), poly-dispersity index (0.011 ± 0.01), zeta-potential (31.9 ± 0.3 mV), and entrapment% (90.9 ± 0.5) with improved ex-vivo pharmacokinetic parameters and ex-vivo trans-corneal penetrability, compared with drug solution. Confocal laser scanning revealed valuable penetration of fluoro-labeled nanoparticles. Irritation tests (Draize Test), Atomic force microscopy, cell culture and animal tests including histopathological analysis revealed superiority of the nanoparticles in reducing signs of inflammation and eradication of fungal infection in rabbits, without causing any damage to rabbit eyeballs. The nanoparticles exhibited favorable pharmacodynamic features with sustained release profile, and is neither cytotoxic nor irritating in-vitro or in-vivo. The developed formulation might provide a new and safe nanotechnology for treating eye problems, like inflammation and fungal infections.

Nutritional and metabolic management of COVID-19 intensive care patients.

Nutritional and metabolic disturbances are observed in patients critically ill with Coronavirus disease 19 (COVID-19) patients. The aim of this review is to describe these disturbances during the progression of the disease, from the pre-intubation phase through the ventilated condition to the post extubation phase. The analysis of new data describing the prevalence of malnutrition, the modifications in energy expenditure and body composition are guiding medical nutritional therapy to prevent patients from experiencing severe energy deficit and muscle loss. Rehabilitation may be extremely prolonged and therefore, nutrition is mandatory to decrease this recondition period. This review also comments on the European Society of Parenteral and Enteral Nutrition (ESPEN) nutritional statements.

Controlled release nanomedicine (CRNM) of aspirin using "biomimetic niosomal nanoparticles (BNNs)”for Covid-19 and cardiovascular treatment: DOE based optimization

Biomimetic strategies can be adopted to improve biopharmaceutical aspects. Subsequently, Biomimetic reconstitutable pegylated amphiphilic lipid nanocarriers have high translational potential for systemic controlled drug delivery;however, such an improvised system for systemic aspirin delivery exploring nanotechnology is not available. Systemic administration of aspirin and its controlled delivery can significantly control blood clotting events, leading to stroke, which has immediate applications in cardiovascular diseases and Covid-19. In this work, we are developing aspirin sustained release pegylated amphiphilic self-assembling nanoparticles to develop reconstitutable aspirin injections by solvent-based co-precipitation method with phase inversion technique that leads to novel "biomimetic niosomal nanoparticles (BNNs).” DOE led optimization is done to develop Design of space for optimized particles. Upon reconstitution of solid powder, the particle size was 144.8 ± 12.90 nm with a surface charge of -29.2 ± 2.24 mV. The entrapment efficiency was found to be 49 ± 0.15%, wherein 96.99 ± 1.57% of the drug was released in 24hr showing super case II transport-based drug release mechanism. The formulation has the least hemolysis while showing significant suppression of platelet aggregation. MTT assay does not show any significant cytotoxicity. This is a potential nanoparticle that can be explored for developing aspirin injection, which is not available.

Biobased polymer SF/PHBV composite nanofiber membranes as filtration and protection materials

With the emergence of the COVID-19, masks and protective clothing have been used in huge quantities. A large number of non-degradable materials have severely damaged the ecological environment. Now, people are increasingly pursuing the use of environmentally friendly materials to replace traditional chemical materials. Silk fibroin (SF) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) have received increasing attention because of their unique biodegradability and biocompatibility. In this paper, a series of biodegradable SF/PHBV nanofiber membranes with different PHBV content were fabricated by using electrospinning technology. The morphology of the electrospun SF/PHBV composite nanofiber was observed by scanning electron microscopy (SEM). The average diameters of the pure SF, SF/PHBV (4/1), SF/PHBV (3/1), and SF/PHBV (2/1) nanofibers were 55.16 ± 12.38 nm, 75.93 ± 21.83 nm, 69.35 ± 21.55 nm, and 61.40 ± 12.31 nm, respectively. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were used to explore the microstructure of the electrospun SF/PHBV composite nanofiber. The crystallization ability of the composite nanofiber was greatly improved with the addition of PHBV. The results of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated that the thermal stability of SF was better than PHBV obviously, so SF could improve the thermal stability of the composite materials within a certain range. The mechanical properties of the electrospun nanofiber membranes were evaluated by using a universal testing machine. In general, the elongation of the composite nanofiber membranes decreased, and the breaking strength increased with the addition of PHBV. The small pore size of the nanofiber membranes ensured that they had good application prospects in the field of filtration and protection. When the spinning time was 1 h, the filtration efficiency of SF/PHBV/PLA composite materials remained above 95%. © 2021 The Textile Institute.

Thermodynamic analysis of the interactions between human ACE2 and Spike RBD of Betacoronaviruses (SARS-CoV-1 and SARS-CoV-2).

There are many scientific reports on the interaction of the SARS-CoV-2 virus S protein (and its RBD) with the human ACE2 receptor protein. However, there are no reliable data on how this interaction differs from the interaction of the receptor binding domain of SARS-CoV-1 with ACE2, in terms of binding strength and changes in reaction enthalpy and entropy. Our studies have revealed these differences as well as the impact of zinc ions on this interaction. Intriguingly, the binding affinity of both RBDs (of SARS-CoV-1 and of SARS-CoV-2) to the ACE2 receptor protein is almost identical; however, there are some differences in the entropic and enthalpic contributions to these interactions.

Biothermodynamics of Viruses from Absolute Zero (1950) to Virothermodynamics (2022).

Biothermodynamics of viruses is among the youngest but most rapidly developing scientific disciplines. During the COVID-19 pandemic, it closely followed the results published by molecular biologists. Empirical formulas were published for 50 viruses and thermodynamic properties for multiple viruses and virus variants, including all variants of concern of SARS-CoV-2, SARS-CoV, MERS-CoV, Ebola virus, Vaccinia and Monkeypox virus. A review of the development of biothermodynamics of viruses during the last several decades and intense development during the last 3 years is described in this paper.

Exploring Highly Conserved Regions of SARS-CoV-2 Spike S2 Subunit as Targets for Fusion Inhibition Using Chimeric Proteins.

Since the beginning of the COVID-19 pandemic, considerable efforts have been made to develop protective vaccines against SARS-CoV-2 infection. However, immunity tends to decline within a few months, and new virus variants are emerging with increased transmissibility and capacity to evade natural or vaccine-acquired immunity. Therefore, new robust strategies are needed to combat SARS-CoV-2 infection. The viral spike composed of S1 and S2 subunits mediates viral attachment and membrane fusion to infect the host cell. In this process, interaction between the highly conserved heptad repeat 1 and 2 regions (HR1 and HR2) of S2 is crucial and for this reason; these regions are promising targets to fight SARS-CoV-2. Here, we describe the design and characterization of chimeric proteins that structurally imitate the S2 HR1 region in a trimeric coiled-coil conformation. We biophysically characterized the proteins and determined their capacity to bind the HR2 region, as well as their inhibitory activity of SARS-CoV-2 infection in vitro. HR1 mimetic proteins showed conformational heterogeneity and a propensity to form oligomers. Moreover, their structure is composed of subdomains with varied stability. Interestingly, the full HR1 proteins showed high affinity for HR2-derived peptides and SARS-CoV-2 inhibitory activity, whereas smaller proteins mimicking HR1 subdomains had a decreased affinity for their complementary HR2 region and did not inhibit the virus. The results provide insight into effective strategies to create mimetic proteins with broad inhibitory activity and therapeutic potential against SARS-CoV-2.

Spike protein receptor-binding domains from SARS-CoV-2 variants of interest bind human ACE2 more tightly than the prototype spike protein.

Several SARS-CoV-2 variants of interest (VOI) have emerged since this virus was first identified as the etiologic agent responsible for COVID-19. Some of these variants have demonstrated differences in both virulence and transmissibility, as well as in evasion of immune responses in hosts vaccinated against the original strain of SARS-CoV-2. There remains a lack of definitive evidence that identifies the genetic elements that are responsible for the differences in transmissibility among these variants. One factor affecting transmissibility is the initial binding of the surface spike protein (SP) of SARS-CoV-2 to human angiotensin converting enzyme-2 (hACE2), the widely accepted receptor for SP. This step in the viral replication process is mediated by the receptor binding domain (RBD) of SP that is located on the surface of the virus. This current study was conducted with the aim of assessing potential differences in binding affinity between recombinant hACE2 and the RBDs of emergent SARS-CoV-2 WHO VOIs. Mutations that affect the binding affinity of SP play a dominant initial role in the infectivity of the virus.

Evaluation of the polymorphic forms of ritonavir and lopinavir in raw materials and co-milled systems.

Recently, the U.S. Food and Drug Administration (FDA) approved the first oral antiviral drug to treat mild to moderate cases of coronavirus disease. The combination of nirmatrelvir with an already used protease inhibitor class drug, ritonavir, has led to Paxlovid®. Several studies considered drug repositioning as the first trial for new drugs. The precise identification and quantification of polymorphs in raw materials and finished products are important to researchers involved in pharmaceutical development and quality control processes. In this work, we study the solid-state behavior of the antiretroviral drugs ritonavir and lopinavir in raw materials and in milled compositions. The results indicate that mixtures of ritonavir Forms I and II are found in different batches of raw materials from the same manufacturer; besides three equal crystalline samples, an amorphous batch was found in lopinavir. Furthermore, the milling process of the already amorphous lopinavir seems to facilitate the amorphization of ritonavir as well as the production of some unexpected crystalline forms of ritonavir. A phase transition of ritonavir Form I to Form II is only observed when co-milling with amorphous lopinavir. These findings reveal significant variations in phase purity of raw materials that affect the processing and solid-state properties, representing risks for the product quality.

Microwave treatment to optimize physicochemical properties of modified Busil (Xanthosoma sagittifolium) starch

COVID-19 pandemic encourages the utilization of local food sources to ensure food availability. Busil (Xanthosoma sagittifolium) was readily available and affordable in Banjarnegara Regency in the Province of Central Java in Indonesia. However, the busil starch utilization was still rare due to the low functional properties of the native busil starch. The objective of this study was to explore busil starch physicochemical characterization enhancement after microwave irradiation treatment, especially on the stability of heat processing. This research was conducted in two steps. First, microwave treatment (with a variation of energy and irradiation time) of native busil starch (NBS), and the second was modified busil starch (MBS) physicochemical characterization. A rise in amylose was observed on MBS. SEM analysis was shown MBS granules are breakdown. Through viscosity, final viscosity, setback viscosity, peak time, and the pasting temperature of MBS generally were increased. Meanwhile, peak viscosity and breakdown viscosity of MBS was decreased. Thermal properties of MBS like onset (To), peak (Tp), and conclusion (Tc) temperatures were also increased. The degree of whiteness index (DW) of MBS was decreased. FTIR analysis has shown that microwave treatment did not cause functional group alteration. XRD analysis has also demonstrated no change in the diffraction pattern but a slight change in the crystallinity index. Generally, microwave treatment leads to MBS thermal stability and potentially broaden MBS utilization on food processing product.

Forces Driving a Magic Bullet to Its Target: Revisiting the Role of Thermodynamics in Drug Design, Development, and Optimization.

Drug discovery strategies have advanced significantly towards prioritizing target selectivity to achieve the longstanding goal of identifying "magic bullets" amongst thousands of chemical molecules screened for therapeutic efficacy. A myriad of emerging and existing health threats, including the SARS-CoV-2 pandemic, alarming increase in bacterial resistance, and potentially fatal chronic ailments, such as cancer, cardiovascular disease, and neurodegeneration, have incentivized the discovery of novel therapeutics in treatment regimens. The design, development, and optimization of lead compounds represent an arduous and time-consuming process that necessitates the assessment of specific criteria and metrics derived via multidisciplinary approaches incorporating functional, structural, and energetic properties. The present review focuses on specific methodologies and technologies aimed at advancing drug development with particular emphasis on the role of thermodynamics in elucidating the underlying forces governing ligand-target interaction selectivity and specificity. In the pursuit of novel therapeutics, isothermal titration calorimetry (ITC) has been utilized extensively over the past two decades to bolster drug discovery efforts, yielding information-rich thermodynamic binding signatures. A wealth of studies recognizes the need for mining thermodynamic databases to critically examine and evaluate prospective drug candidates on the basis of available metrics. The ultimate power and utility of thermodynamics within drug discovery strategies reside in the characterization and comparison of intrinsic binding signatures that facilitate the elucidation of structural-energetic correlations which assist in lead compound identification and optimization to improve overall therapeutic efficacy.