Remdesivir-Loaded Nanoliposomes Stabilized by Chitosan/Hyaluronic Acid Film with a Potential Application in the Treatment of Coronavirus Infection

An object of the present study was the development of liposomes loaded with the medicine Veklury® (remdesivir) stabilized by electrostatic adsorption of polysaccharide film formed from chitosans with different physicochemical characteristics and hyaluronic acid. The functionalization of the structures was achieved through the inclusion of an aptamer (oligonucleotide sequence) with specific affinity to the spike protein of the human coronavirus HCoV-OC43. The hydrodynamic size, electrokinetic potential and stability of the structures were evaluated at each step in the procedure. The encapsulation efficiency and loaded amount of remdesivir (99% and 299 µg/mL) were estimated by UV-vis spectroscopy. Our investigations showed manifestation of promising tendencies for prolonged periods of the drug release and increased effectiveness of its antiviral action. Among all studied versions of the delivery system, the most distinguished and suitable in a model coronavirus therapy are the liposomes formed from chitosan oligosaccharides. The cytotoxicity of the liposomes was determined against the HCT-8 cell line. A cytopathic effect inhibition test was used for the assessment of the antiviral activity of the compounds. The virucidal activity and the effect on the viral adsorption of the samples were reported by the end-point dilution method, and the alteration in viral titer was determined as Δlgs compared to untreated controls. The redox-modulating properties of the nanoparticles were studied in vitro in certain/several/a few chemical model systems. Our investigations showed a manifestation of promising tendencies for a prolonged effect of the drug release and increased effectiveness of its antiviral action.

Lysosomal nanotoxicity: Impact of nanomedicines on lysosomal function

Although several nanomedicines got clinical approval over the past two decades, the clinical translation rate is relatively small so far. There are many post-surveillance withdrawals of nanomedicines caused by various safety issues. For successful clinical advancement of nanotechnology, it is of unmet need to realize cellular and molecular foundation of nanotoxicity. Current data suggest that lysosomal dysfunction caused by nanoparticles is emerging as the most common intracellular trigger of nanotoxicity. This review analyzes prospect mechanisms of lysosomal dysfunction-mediated toxicity induced by nanoparticles. We summarized and critically assessed adverse drug reactions of current clinically approved nanomedicines. Importantly, we show that physicochemical properties have great impact on nanoparticles interaction with cells, excretion route and kinetics, and subsequently on toxicity. We analyzed literature on adverse reactions of current nanomedicines and hypothesized that adverse reactions might be linked with lysosomal dysfunction caused by nanomedicines. Finally, from our analysis it becomes clear that it is unjustifiable to generalize safety and toxicity of nanoparticles, since different particles possess distinct toxicological properties. We propose that the biological mechanism of the disease progression and treatment should be central in the optimization of nanoparticle design.

Biomedical Applications of Metal-Organic Frameworks for Disease Diagnosis and Drug Delivery: A Review

Metal-organic frameworks (MOFs) are a novel class of porous hybrid organic-inorganic materials that have attracted increasing attention over the past decade. MOFs can be used in chemical engineering, materials science, and chemistry applications. Recently, these structures have been thoroughly studied as promising platforms for biomedical applications. Due to their unique physical and chemical properties, they are regarded as promising candidates for disease diagnosis and drug delivery. Their well-defined structure, high porosity, tunable frameworks, wide range of pore shapes, ultrahigh surface area, relatively low toxicity, and easy chemical functionalization have made them the focus of extensive research. This review highlights the up-to-date progress of MOFs as potential platforms for disease diagnosis and drug delivery for a wide range of diseases such as cancer, diabetes, neurological disorders, and ocular diseases. A brief description of the synthesis methods of MOFs is first presented. Various examples of MOF-based sensors and DDSs are introduced for the different diseases. Finally, the challenges and perspectives are discussed to provide context for the future development of MOFs as efficient platforms for disease diagnosis and drug delivery systems.

Nanoapproaches to Modifying Epigenetics of Epithelial Mesenchymal Transition for Treatment of Pulmonary Fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a chronically progressive interstitial lung that affects over 3 M people worldwide and rising in incidence. With a median survival of 2-3 years, IPF is consequently associated with high morbidity, mortality, and healthcare burden. Although two antifibrotic therapies, pirfenidone and nintedanib, are approved for human use, these agents reduce the rate of decline of pulmonary function but are not curative and do not reverse established fibrosis. In this review, we discuss the prevailing epithelial injury hypothesis, wherein pathogenic airway epithelial cell-state changes known as Epithelial Mesenchymal Transition (EMT) promotes the expansion of myofibroblast populations. Myofibroblasts are principal components of extracellular matrix production that result in airspace loss and mortality. We review the epigenetic transition driving EMT, a process produced by changes in histone acetylation regulating mesenchymal gene expression programs. This mechanistic work has focused on the central role of bromodomain-containing protein 4 in mediating EMT and myofibroblast transition and initial preclinical work has provided evidence of efficacy. As nanomedicine presents a promising approach to enhancing the efficacy of such anti-IPF agents, we then focus on the state of nanomedicine formulations for inhalable delivery in the treatment of pulmonary diseases, including liposomes, polymeric nanoparticles (NPs), inorganic NPs, and exosomes. These nanoscale agents potentially provide unique properties to existing pulmonary therapeutics, including controlled release, reduced systemic toxicity, and combination delivery. NP-based approaches for pulmonary delivery thus offer substantial promise to modify epigenetic regulators of EMT and advance treatments for IPF.

Toxicity and Safety Study of D-PLEX100 in a Sternal Surgical Defect in New Zealand White Rabbits

Bacterial infections are a common complication after surgical procedures. Therefore, local delivery of antibiotics has been developed, including the use of biodegradable polymers. A newly developed product for prevention of surgical site infections is a polymer-lipid encapsulation matrix loaded with doxycycline, named D-PLEX₁₀₀ (D-PLEX). We evaluated the toxicity and safety of D-PLEX using a sternal surgical defect model in rabbits. D-PLEX was tested with three different concentrations of doxycycline in comparison to sham-operated control after administration into the sternal surgical defect and on the ventral side of the sternum in New Zealand White (NZW) rabbits, following 15 months of exposure. No mortality or abnormal clinical findings were attributed to D-PLEX, and clinical pathology assays were normal. Histological examinations revealed no treatment-related adverse findings in any of the examined tissues, including the osseous and surrounding soft tissues. It has been shown that D-PLEX gradually degraded until complete disappearance after 9 months, and mainly during the first 3 months, in parallel to normal bone formation. In addition, the administration of D-PLEX did not affect sternal bone strength. This study adds to the growing data on preclinical safety studies utilizing biodegradable materials and provides information on the expected normal reaction to biodegradable materials in the sternum of NZW rabbits.

Unintended effects of drug carriers: Big issues of small particles

Humoral and cellular host defense mechanisms including diverse phagocytes, leukocytes, and immune cells have evolved over millions of years to protect the body from microbes and other external and internal threats. These policing forces recognize engineered sub-micron drug delivery systems (DDS) as such a threat, and react accordingly. This leads to impediment of the therapeutic action, extensively studied and discussed in the literature. Here, we focus on side effects of DDS interactions with host defenses. We argue that for nanomedicine to reach its clinical potential, the field must redouble its efforts in understanding the interaction between drug delivery systems and the host defenses, so that we can engineer safer interventions with the greatest potential for clinical success.

Ciprofloxacin-loaded PLGA nanoparticles against cystic fibrosis P. aeruginosa lung infections

Current pulmonary treatments against Pseudomonas aeruginosa infections in cystic fibrosis (CF) lung suffer from deactivation of the drug and immobilization in thick and viscous biofilm/mucus blend, along with the general antibiotic resistance. Administration of nanoparticles (NPs) with high antibiotic load capable of penetrating the tight mesh of biofilm/mucus can be an advent to overcome the treatment bottlenecks. Biodegradable and biocompatible polymer nanoparticles efficiently loaded with ciprofloxacin complex offer a solution for emerging treatment strategies. NPs were prepared under controlled conditions by utilizing MicroJet Reactor (MJR) to yield a particle size of 190.4±28.6nm with 0.089 PDI. Encapsulation efficiency of the drug was 79% resulting in a loading of 14%. Release was determined to be controlled and medium-independent in PBS, PBS+0.2% Tween 80 and simulated lung fluid. Cytotoxicity assays with Calu-3 cells and CF bronchial epithelial cells (CFBE41o^-) indicated that complex-loaded PLGA NPs were non-toxic at concentrations ≫ MIC_cipro against lab strains of the bacteria. Antibacterial activity tests revealed enhanced activity when applied as nanoparticles. NPs' colloidal stability in mucus was proven. Notably, a decrease in mucus turbidity was observed upon incubation with NPs. Herewith, ciprofloxacin complex-loaded PLGA NPs are introduced as promising pulmonary nano drug delivery systems against P.aeruginosa infections in CF lung.

Airway reflux

An ever-increasing number of adult and pediatric disorders have been shown to be influenced or caused by airway reflux. This has become a controversial and complicated aspect of medicine that requires a multidisciplinary approach. Evidence indicates that it is not only the acidic components of gastric refluxate that injure extraesophageal tissues but also the nonacidic components, such as pepsin and bile. There is a realization that proton pump inhibitors will not be effective when nonacidic components of refluxate are causing the problem. New in vitro and in vivo models for the study of airway reflux and new therapeutic and surgical approaches are discussed in this review article.

Disposition and safety of inhaled biodegradable nanomedicines: Opportunities and challenges

The inhaled delivery of nanomedicines can provide a novel, non-invasive therapeutic strategy for the more localised treatment of lung-resident diseases and potentially also enable the systemic delivery of therapeutics that are otherwise administered via injection alone. However, the clinical translation of inhalable nanomedicine is being hampered by our lack of understanding about their disposition and clearance from the lungs. This review provides a comprehensive overview of the biodegradable nanomaterials that are currently being explored as inhalable drug delivery systems and our current understanding of their disposition within, and clearance from the lungs. The safety of biodegradable nanomaterials in the lungs is discussed and latest updates are provided on the impact of inflammation on the pulmonary pharmacokinetics of inhaled nanomaterials. Overall, the review provides an in-depth and critical assessment of the lung clearance mechanisms for inhaled biodegradable nanomedicines and highlights the opportunities and challenges for their translation into the clinic.

Prolonged vasodilatory response to nanoencapsulated sildenafil in pulmonary hypertension

Direct vasodilator delivery to the airways enables a selective therapy of pulmonary hypertension (PH). However, short-term effects of the applied medication require multiple daily inhalations. Controlled release formulations (polymeric nanomedicines) offer the potential of prolonging drug effects within the respiratory tract, thereby reducing the number of necessary inhalations. In the model of U46619-elicited PH, sildenafil and two sildenafil-loaded polymeric submicron particle formulations were evaluated for their pharmacodynamic and pharmacokinetic characteristics and acute tolerability. Lung-delivered sildenafil caused a selective dose-dependent decline of the pulmonary arterial pressure and vascular resistance. Compared to the transient pharmacodynamic effect observed for sildenafil, the same dose of nanoencapsulated sildenafil resulted in prolongation, but not augmentation, of the pulmonary vasodilatation. An extended pharmacokinetic profile was observed for nanoencapsulated sildenafil, and nanomedicines revealed no acute toxicity. The amplification of pulmonary vasodilatory response caused by nanoencapsulation of sildenafil offers an intriguing approach to ameliorate the therapy of PH. From the Clinical Editor: Pulmonary hypertension usually results in right heart failure long term. Current medical therapy includes the use of potent vasodilators such as sildenafil. In this article, the authors investigated the use of nanoencapsulated formulation for sustained delivery via inhalation route. An extended pharmacokinetic profile was seen for this nanoformulation with little side effects. It is hoped that clinical application of this would come to fruition soon.