Preparation and characterization of quercetin-loaded solid lipid microparticles for pulmonary delivery

Flavonoids for treating pulmonary fibrosis: Present status and future prospects

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with an unknown underlying cause. There is no complete cure for IPF; however, two anti-fibrotic agents (Nintedanib and pirfenidone) are approved by the USFDA to extend the patient's life span. Therefore, alternative therapies supporting the survival of fibrotic patients have been studied in recent literature. The abundance of phenolic compounds, particularly flavonoids, has gathered attention due to their potential health benefits. Various flavonoids, like naringin, quercetin, baicalin, baicalein, puerarin, silymarin, and kaempferol, exhibit anti-inflammatory and anti-oxidant properties, which help decrease lung fibrosis. Various databases, including PubMed, EBSCO, ProQuest, and Scopus, as well as particular websites, such as the World Health Organisation and the National Institutes of Health, were used to conduct a literature search. Several mechanisms of action of flavonoids are reported with the help of in vivo and cell line studies emphasizing their ability to modulate oxidative stress, inflammation, and fibrotic processes in the lungs. They are reported for the restoration of biomarkers like hydroxyproline, cytokines, superoxide dismutase, malondialdehyde and others associated with IPF and for modulating various pathways responsible for the progression of pulmonary fibrosis. Yet, flavonoids have some drawbacks, such as poor solubility, challenging drug loading, stability issues, and scarce bioavailability. Therefore, novel formulations of flavonoids are explored, including liposomes, solid lipid microparticles, polymeric nanoparticles, nanogels, and nanocrystals, to enhance the therapeutic efficacy of flavonoids in pulmonary fibrosis. This review focuses on the role of flavonoids in mitigating idiopathic pulmonary fibrosis, their mode of action and novel formulations.

Quercetin Loaded Cationic Solid Lipid Nanoparticles in a Mucoadhesive In Situ Gel-A Novel Intravesical Therapy Tackling Bladder Cancer

The study aim was to develop an intravesical delivery system of quercetin for bladder cancer management in order to improve drug efficacy, attain a controlled release profile and extend the residence time inside the bladder. Either uncoated or chitosan coated quercetin-loaded solid lipid nanoparticles (SLNs) were prepared and evaluated in terms of colloidal, morphological and thermal characteristics. Drug encapsulation efficiency and its release behaviour were assessed. Furthermore, cytotoxicity of SLNs on T-24 cells was evaluated. Ex vivo studies were carried out using bovine bladder mucosa. Spherical SLNs (≈250 nm) ensured good entrapment efficiencies (EE > 97%) and sustained drug release up to 142 h. Cytotoxicity profile revealed concentration-dependent toxicity recording an IC50 in the range of 1.6−8.9 μg/mL quercetin. SLNs were further dispersed in in situ hydrogels comprising poloxamer 407 (20%) with mucoadhesive polymers. In situ gels exhibited acceptable gelation temperatures (around 25 °C) and long erosion time (24−27 h). SLNs loaded gels displayed remarkably enhanced retention on bladder tissues relative to SLNs dispersions. Coated SLNs exhibited better penetration abilities compared to uncoated ones, while coated SLNs dispersed in gel (G10C-St-QCT-SLNs-2) showed the highest penetration up to 350 μm. Hence, G10C-St-QCT-SLNs-2 could be considered as a platform for intravesical quercetin delivery.

Microfluidic preparation of antimicrobial microparticles composed of l-lactide/1,3-dioxolane (co)polymers loaded with quercetin

The resistance of microorganisms against commonly used antibiotics is becoming an increasingly important problem in the food and pharmaceutical industries. Therefore, the development of novel bactericidal agents, as well as the design of drug delivery systems based on materials composed of biocompatible and biodegradable building blocks, has attracted increasing attention. To address this challenge, microparticles composed of l-lactide homopolymer and l-lactide/1,3-dioxolane (co)polymers loaded with quercetin (Q) were fabricated by using a microfluidic technique. This method enables the preparation of homogeneous particles with sizes ranging from 60 to 80 µm, composed of degradable semicrystalline or amorphous (co)polyesters. The microencapsulation of Q in a (co)polymeric matrix enables prolonged release of the antimicrobial agent. The antibacterial properties of the obtained biocompatible microparticles are confirmed by the agar diffusion plate method for various bacterial strains. Therefore, Q-loaded microparticles can have important applications in food preservation as a novel antimicrobial system.

Preparation and Characterization of Chitosan-Alginate Microspheres Loaded with Quercetin

The aim of this paper was to formulate microspheres based on biodegradable polymers (chitosan and sodium alginate), using the complex coacervation technique. Subsequently, the prepared microspheres were loaded with quercetin (QUE), a pharmacological active ingredient insoluble in water and unstable to light, temperature and air. After preparation, the loaded microspheres underwent several studies for physical chemical characterization (performed by scanning electron microscopy-SEM, laser 3D scanning, and thermal analysis-TA). Furthermore, they were analyzed in order to obtain information regarding swelling index, drug entrapment, and in vitro release capacity. The obtained experimental data demonstrated 86.07% entrapment of QUE into the microspheres, in the case of the one with the highest Ch concentration. Additionally, it was proved that such systems allow the controlled release of the active drug over 24 h at the intestinal level. SEM micrographs proved that the prepared microspheres have a wrinkled surface, with compact structures and a large number of folds. On the basis of the TA analysis, it was concluded that the obtained microspheres were thermally stable, facilitating their usage at normal physiological temperatures as drug delivery systems.

Modern Nanocarriers as a Factor in Increasing the Bioavailability and Pharmacological Activity of Flavonoids

This review is devoted to modern systems of nanocarriers that ensure the targeted delivery of flavonoids to various organs and systems. Flavonoids have wide range of effects on the human body due to their antioxidant, anti-inflammatory, antitumor, antimicrobial, antiplatelet and other types of activity. However, the low bioavailability of flavonoids significantly limits their practical application. To overcome this disadvantage, serious efforts have been made in recent years to develop nanoscale carriers for flavonoids. This is particularly important in view of the known antitumor effect of these compounds, which allows them to target tumor cells without affecting surrounding healthy tissues. Nanocarriers provide increased penetration of biologicals into specific organs in combination with controlled and prolonged release, which markedly improves their effectiveness. This review summarizes data on the use of phytosomes, lipid-based nanoparticles, as well as polymeric and inorganic nanoparticles; their advantages and drawbacks are analyzed; the prospect of their use is discussed that opens new possibilities for the clinical application of flavonoids.

Repurpose but also (nano)-reformulate! The potential role of nanomedicine in the battle against SARS-CoV2

The coronavirus disease-19 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) has taken the world by surprise. To date, a worldwide approved treatment remains lacking and hence in the context of rapid viral spread and the growing need for rapid action, drug repurposing has emerged as one of the frontline strategies in the battle against SARS-CoV2. Repurposed drugs currently being evaluated against COVID-19 either tackle the replication and spread of SARS-CoV2 or they aim at controlling hyper-inflammation and the rampaged immune response in severe disease. In both cases, the target for such drugs resides in the lungs, at least during the period where treatment could still provide substantial clinical benefit to the patient. Yet, most of these drugs are administered systemically, questioning the percentage of administered drug that actually reaches the lung and as a consequence, the distribution of the remainder of the dose to off target sites. Inhalation therapy should allow higher concentrations of the drug in the lungs and lower concentrations systemically, hence providing a stronger, more localized action, with reduced adverse effects. Therefore, the nano-reformulation of the repurposed drugs for inhalation is a promising approach for targeted drug delivery to lungs. In this review, we critically analyze, what nanomedicine could and ought to do in the battle against SARS-CoV2. We start by a brief description of SARS-CoV2 structure and pathogenicity and move on to discuss the current limitations of repurposed antiviral and immune-modulating drugs that are being clinically investigated against COVID-19. This account focuses on how nanomedicine could address limitations of current therapeutics, enhancing the efficacy, specificity and safety of such drugs. With the appearance of new variants of SARS-CoV2 and the potential implication on the efficacy of vaccines and diagnostics, the presence of an effective therapeutic solution is inevitable and could be potentially achieved via nano-reformulation. The presence of an inhaled nano-platform capable of delivering antiviral or immunomodulatory drugs should be available as part of the repertoire in the fight against current and future outbreaks.

Emerging Advances of Nanotechnology in Drug and Vaccine Delivery against Viral Associated Respiratory Infectious Diseases (VARID)

Viral-associated respiratory infectious diseases are one of the most prominent subsets of respiratory failures, known as viral respiratory infections (VRI). VRIs are proceeded by an infection caused by viruses infecting the respiratory system. For the past 100 years, viral associated respiratory epidemics have been the most common cause of infectious disease worldwide. Due to several drawbacks of the current anti-viral treatments, such as drug resistance generation and non-targeting of viral proteins, the development of novel nanotherapeutic or nano-vaccine strategies can be considered essential. Due to their specific physical and biological properties, nanoparticles hold promising opportunities for both anti-viral treatments and vaccines against viral infections. Besides the specific physiological properties of the respiratory system, there is a significant demand for utilizing nano-designs in the production of vaccines or antiviral agents for airway-localized administration. SARS-CoV-2, as an immediate example of respiratory viruses, is an enveloped, positive-sense, single-stranded RNA virus belonging to the coronaviridae family. COVID-19 can lead to acute respiratory distress syndrome, similarly to other members of the coronaviridae. Hence, reviewing the current and past emerging nanotechnology-based medications on similar respiratory viral diseases can identify pathways towards generating novel SARS-CoV-2 nanotherapeutics and/or nano-vaccines.

Solid Lipid Nanoparticles Produced via a Coacervation Method as Promising Carriers for Controlled Release of Quercetin

Quercetin is a poorly water-soluble flavonoid with many benefits to human health. Besides the natural food resources that may provide Quercetin, the interest in delivery systems that could enhance its bioavailability in the human body has seen growth in recent years. Promising delivery system candidates are represented by Solid Lipid Nanoparticles (SLNs) which are composed of well-tolerated compounds and provide a relatively high encapsulation efficiency and suitable controlled release. In this study, Quercetin-loaded and negatively charged Solid Lipid Nanoparticles were synthesized based on a coacervation method, using stearic acid as a core lipid and Arabic Gum as a stabilizer. Samples were qualitatively characterized by Dynamic light scattering (DLS), Zeta Potential, Surface infrared spectroscopy (FTIR-ATR), and Time of flight secondary ion mass spectrometry (ToF-SIMS). Encapsulation efficiency, drug release, and antioxidant effect against ABTS•+ were evaluated in vitro by UV-VIS spectrophotometry.

Progress in the Application of Nano- and Micro-based Drug Delivery Systems in Pulmonary Drug Delivery

Nanotechnology is associated with the development of particles in the nano-size range that can be used in a wide range of applications in the medical field. It has gained more importance in the pharmaceutical research field particularly in drug delivery, as it results in enhanced therapeutic drug performance, improved drug solubility, targeted drug delivery to the specific sites, minimized side effects, and prolonged drug retention time in the targeted site. To date, the application of nanotechnology continues to offer several benefits in the treatment of various chronic diseases and results in remarkable improvements in treatment outcomes. The use of nano-based delivery systems such as liposomes, micelles, and nanoparticles in pulmonary drug delivery have shown to be a promising strategy in achieving drug deposition and maintained controlled drug release in the lungs. They have been widely used to minimize the risks of drug toxicity in vivo. In this review, recent advances in the application of nano- and micro-based delivery systems in pulmonary drug delivery for the treatment of various pulmonary diseases, such as lung cancer, asthma, and chronic obstructive pulmonary disease, are highlighted. Limitations in the application of these drug delivery systems and some key strategies in improving their formulation properties to overcome challenges encountered in drug delivery are also discussed.

Pulmonary route of administration is instrumental in developing therapeutic interventions against respiratory diseases

Pulmonary route of drug delivery has drawn significant attention due to the limitations associated with conventional routes and available treatment options. Drugs administered through pulmonary route has been an important research area that focuses on to developing effective therapeutic interventions for asthma, chronic obstructive pulmonary disease, tuberculosis, lung cancer etc. The intravenous route has been a natural route of delivery of proteins and peptides but associated with several issues including high cost, needle-phobia, pain, sterility issues etc. These issues might be addressed by the pulmonary administration of macromolecules to achieving an effective delivery and efficacious therapeutic impact. Efforts have been made to develop novel drug delivery systems (NDDS) such as nanoparticles, microparticles, liposomes and their engineered versions, polymerosomes, micelles etc to achieving targeted and sustained delivery of drug(s) through pulmonary route. Further, novel approaches such as polymer-drug conjugates, mucoadhesive particles and mucus penetrating particles have attracted significant attention due to their unique features for an effective delivery of drugs. Also, use of semi flourinated alkanes is in use for improvising the pulmonary delivery of lipophilic drugs. Present review focuses on to unravel the mechanism of pulmonary absorption of drugs for major pulmonary diseases. It summarizes the development of interventional approaches using various particulate and vesicular drug delivery systems. In essence, the orchestrated attempt presents an inflammatory narrative on the advancements in the field of pulmonary drug delivery.

Ethambutol-Loaded Solid Lipid Nanoparticles as Dry Powder Inhalable Formulation for Tuberculosis Therapy

Ethambutol hydrocloride (EMB) is an anti-tuberculosis drug, which is commonly used as a protection agent against of unrecognized resistance to other drugs employed to treat this disease. Since oral form of EMB has some side effects and cellular toxicity, direct administration of EMB into lungs seems to be an attractive and reasonable option in order to overcome these side effects. Our main goal in this study was assessment of pulmonary administration through dry powder inhaler (DPI) using EMB-loaded solid lipid nanoparticles (SLNs). We prepared EMB-loaded SLNs using two techniques (hot homogenization and ultrasonication). DPI formulations were made by spray drying of EMB-loaded SLNs with and without mannitol. For investigation of flowbility of the prepared powders, Carr's index and Hausner ratio, and for in vitro deposition of the powders, Next Generation Impactor (NGI) analysis were used. The encapsulation efficiency and particle size of obtained particles were higher than 98% and sub-100 nm, respectively. Toxicity investigation of EMB-loaded SLNs via MTT assay showed biocompatibility and non-toxicity of the SLNs. Results of flowability and aerodynamic traits assessment of EMB-loaded SLN DPI powder confirmed the suitability of prepared powders. Overall, the attained results showed that EMB-loaded SLN DPI has high potential for direct treatment of tuberculosis.

Phytoconstituent based dry powder inhalers as biomedicine for the management of pulmonary diseases

Pulmonary disease represents a major global health issue. They are commonly treated by various synthetic molecules. But, frequent high-dose of oral and injectable drugs may lead to severe side effects and this juncture demands inhaled formulations that facilitate effective drug delivery to the lower airways with negligible side effects. Natural phytoconstituents or phytoalexin (i.e. plant antibiotics) have showed an unique treatment array with minimum side effects and great capability to treat intrapulmonary and extrapulmonary diseases compared to synthetic drugs. Moreover, the progress of disciplines such as nanotechnology, material science and particle engineering allows further improvement of the treatment capability and efficiency. This article review and analyze literatures on inhaled phytoconstituents which were published in the last 10 years. Additionally, it will also offer the researcher with some basic background information for phytoconstituents profile, formulation requirements and drug delivery systems.

Pulmonary delivery systems for polyphenols

This review reports on the beneficial pharmacological properties of naturally occurring polyphenols for the treatment of inflammatory pulmonary diseases. In addition, it presents an overview of the different types of inhalable formulations which have been developed in order to achieve efficient delivery of polyphenols to the respiratory tract. The main biological activities of polyphenols (anti-oxidant and anti-inflammatory) are covered, with particular emphasis on the studies describing their therapeutic effects on different factors and conditions characteristic of lung pathologies. Special focus is on the technological aspects which influence the pulmonary delivery of drugs. The various polyphenol-based inhalable formulations reported in the literature are examined with specific attention to the preparation methodologies, aerosol performance, lung deposition and in vitro and in vivo polyphenol uptake by the pulmonary epithelial cells.

Magnetic solid lipid nanoparticles in hyperthermia against colon cancer

A reproducible double emulsion/solvent evaporation procedure is developed to formulate magnetic solid lipid nanoparticles (average size≈180 nm) made of iron oxide cores embedded within a glyceryl trimyristate solid matrix. The physicochemical characterization of the nanocomposites ascertained the efficacy of the preparation conditions in their production, i.e. surface properties (electrokinetic and thermodynamic data) were almost indistinguishable from those of the solid lipid nanomatrix, while electron microscopy characterizations and X-ray diffraction patterns confirmed the satisfactory coverage of the magnetite nuclei. Hemocompatibility of the particles was established in vitro. Hysteresis cycle determinations defined the appropriate magnetic responsiveness of the nanocomposites, and their heating characteristics were investigated in a high frequency alternating gradient of magnetic field: a constant maximum temperature of 46 °C was obtained within 40 min. Finally, in vitro tests performed on human HT29 colon adenocarcinoma cells demonstrated a promising decrease in cell viability after treatment with the nanocomposites and exposure to that alternating electromagnetic field. To the best of our knowledge, this is the first time that such type of nanoformulation with very promising hyperthermia characteristics has been developed for therapeutic aims.

Development of low density azithromycin-loaded polycaprolactone microparticles for pulmonary delivery

CONTEXT

The development of low-density polymeric microparticles may be a useful approach to deliver antibiotics such as azithromycin into the lung.

OBJECTIVE

The aim of this study was to develop azithromycin-loaded low density polycaprolactone microparticles by the double emulsion/solvent evaporation method.

MATERIALS AND METHODS

Microparticles were prepared and characterized according to their physicochemical properties, drug loading, and drug release profiles. A full 2(3) factorial design was used to evaluate the effect of some independent variables on the drug loading and aerodynamic diameter of the particles. An in silico pulmonary deposition model was used to predict the lung deposition profiles for the formulations.

RESULTS AND DISCUSSION

The resulting particles presented drug loading up to 23.1% (wt%) and mean geometric diameters varying from 4.0 µm to 15.4 µm. Bulk and tapped densities were low, resulting in good or excellent flow properties. SEM images showed spherical particles with a smooth surface. However, hollow inner structures were observed, which may explain the low values of bulk density. The estimated aerodynamic diameters ranged from 2.3 µm to 8.9 µm. The in silico pulmonary deposition profiles indicated, for some formulations, that a significant fraction of the particles would be deposited in the deeper lung regions.

CONCLUSIONS

Statistical analysis demonstrated that not only drug loading but also the aerodynamic diameter of the microparticles is greatly affected by the preparation conditions. Overall, the results indicated that the low-density azithromycin-loaded microparticles with a relatively high respirable fraction may be obtained for the local treatment of lung infections.

Nanoparticle-mediated pulmonary drug delivery: a review

Colloidal drug delivery systems have been extensively investigated as drug carriers for the application of different drugs via different routes of administration. Systems, such as solid lipid nanoparticles, polymeric nanoparticles and liposomes, have been investigated for a long time for the treatment of various lung diseases. The pulmonary route, owing to a noninvasive method of drug administration, for both local and systemic delivery of an active pharmaceutical ingredient (API) forms an ideal environment for APIs acting on pulmonary diseases and disorders. Additionally, this route offers many advantages, such as a high surface area with rapid absorption due to high vascularization and circumvention of the first pass effect. Aerosolization or inhalation of colloidal systems is currently being extensively studied and has huge potential for targeted drug delivery in the treatment of various diseases. Furthermore, the surfactant-associated proteins present at the interface enhance the effect of these formulations by decreasing the surface tension and allowing the maximum effect. The most challenging part of developing a colloidal system for nebulization is to maintain the critical physicochemical parameters for successful inhalation. The following review focuses on the current status of different colloidal systems available for the treatment of various lung disorders along with their characterization. Additionally, different in vitro, ex vivo and in vivo cell models developed for the testing of these systems with studies involving cell culture analysis are also discussed.

Characterization and biodistribution in vivo of quercetin-loaded cationic nanostructured lipid carriers

Nanobiotechnology has been recently viewed as a promising strategy to improve therapy efficacy by promoting the accumulation of hydrophobic bioactive compounds in tissues. The aim of present study was to formulate a novel quercetin-loaded cationic nanostructured lipid carriers (QR-CNLC) and to evaluate its biodistribution in vivo after oral administration. QR-CNLC were prepared by emulsifying at high temperature and subsequent solidifying at low temperature using various functional ingredients, and its characteristics, including physical index, release profile in vitro, and tissue distribution in vivo, were investigated. The results demonstrated that QR-CNLC exhibited an average particle size 126.6 nm, a zeta potential of 40.5 mV and 89.3% entrapment efficiency. QR-CNLC performed slower release compared with quercetin solution in vitro. QR-CNLC showed higher AUC (area under tissue concentration-time curve) value and higher Cmax value in lung, liver and kidney compared with control group. The value of relative intake rate (re) for lung, liver and kidney was 1.57, 1.51 and 1.68, respectively, which revealed that quercetin can be significantly accumulated in lung, kidney and liver after oral administration of QR-CNLC compared with quercetin suspension. In conclusion, cationic nanostructured lipid carriers may be an attractive nanocarrier system for oral delivery of hydrophobic functional components.