Poly(amidoamine) dendrimer nanocarriers and their aerosol formulations for siRNA delivery to the lung epithelium

The (re)emergence of aerosol delivery: Treatment of pulmonary diseases and its clinical challenges

Aerosol delivery represents a rapid and non-invasive way to directly reach the lungs while escaping the hepatic first-pass effect. The development of pulmonary drugs for respiratory diseases such as cystic fibrosis, lung infections, pulmonary fibrosis or lung cancer requires an enhanced understanding of the relationships between the natural physiology of the respiratory system and the pathophysiology of these conditions. This knowledge is crucial to better predict and thereby control drug deposition. Moreover, aerosol administration faces several challenges, including the pulmonary tract, immune system, mucociliary clearance, the presence of fluid on the airway surfaces, and, in some cases, bacterial colonisation. Each of them directly influences on the bioavailability of the active molecule. In addition to these challenges, particle size and the device used to administer the treatment are critical factors that can significantly impact the biodistribution of the drugs. Nanoparticles are very promising in the development of new formulations for aerosol drug delivery, as they can be fine-tuned to reach the entire pulmonary tract and overcome the difficulties encountered along the way. However, to properly assess drug delivery, preclinical studies need to be more thorough to efficiently enhance drug delivery.

Innovative approaches to asthma treatment: harnessing nanoparticle technology

In the domain of respiratory illnesses, asthma remains a critical obstacle. The heterogeneous nature of this chronic inflammatory disease poses challenges during its treatment. Glucocorticoid-based combination drug therapy now dominates clinical treatments for asthma; however, glucocorticoid resistance, numerous adverse effects, the incidence of inadequate drug delivery, and other factors need the development of more effective therapies. In recent years, there has been extensive research on nanotechnology in medicine. It has been shown in studies that these drug delivery systems can greatly enhance targeting and bioavailability and decrease the toxicity of medication. Nanoparticle drug delivery systems offer improved therapeutic efficacy compared to conventional administration techniques. Nanotechnology enables advancements in precision medicine, offering benefits for heterogeneous conditions such as asthma. This review will examine the critical factors of asthma to consider when formulating medications, as well as the role of nanomaterials and their mechanisms of action in pulmonary medicine for asthma treatment.

Dendrimer-mediated proton sponge effect in the treatment of pulmonary acidosis

The present study aimed to synthesize tiotropium bromide (TIO)-loaded generation 5 polyamidoamine dendrimers (TIO-PAMAM-G5-DMs) using a solvent-free microwave assisted synthesis (MAS) for the treatment of pulmonary acidosis, a condition associated with decreased blood pH due to bronchoconstriction. The encapsulation of TIO into PAMAM-G5-DMs was achieved using MAS Michael addition and amidation reactions, following green chemistry principles. The DMs demonstrated particle size of 460.68 ± 1.38 nm, entrapment efficiency of 92.4 ± 0.44%, controlled release profiles of 90.4 ± 0.62% and 76 ± 0.84% in media of pH 6.8 and 7.4, respectively, and high buffering capacity (25 mL/pH units) using a proton sponge effect for the release of the drug into the system as compared to the conventional formulation. A synergistic rat model was used to compare the pharmacokinetics (PK) of marketed and DM-based formulations. The results showed a mean Cmax of 1987 ng/mL, tmax of 6 h, AUC of 10013863.5 ng.h/mL, and t½ of 18.59 h, respectively. The DMs exhibited low cytotoxicity, good biocompatibility, and higher IC50 value (> 10 µg) on human lung epithelial cell line BEAS-2B. Thus, our study introduces a cutting-edge alternative approach for treating pulmonary acidosis using PAMAM-DMs with proton sponge effect.

Polyphenolic dendrimers as carriers of anticancer siRNA

Dendrimers have emerged as an important group of nanoparticles to transport drugs, DNA, or RNA into target cells in cancer and other diseases. Various functional modifications can be imposed on dendrimers to increase the efficacy and specificity in delivering their cargo to the target cells and decrease their toxicity. In the present work, we evaluated the potential of carbosilane polyphenolic dendrimers modified with caffeic acid (CA) and polyethylene glycol (PEG) to deliver proapoptotic Mcl-1 and Bcl-2 siRNAs to A549 cancer cells. Dendrimers formed stable complexes with siRNAs as assessed by transmission electron microscopy and gel electrophoresis. Modification of dendrimers with PEG reduced the size and the zeta potential of dendrimer/siRNA complexes. The presence of PEG caused a red shift of the CD spectrum, and this effect was the more pronounced, the higher the dendrimer/siRNA ratio was. The nanocomplexes were internalized by A549. All studied dendrimer/siRNA formulations inhibited tumor cell migration and adhesion and caused an increase in the population of early apoptotic cells. Among four tested dendrimers, the polyphenolic compound containing two caffeic acid moieties complexed with siRNA demonstrated the lowest polydispersity index and showed an excellent transfection profile. In conclusion, this dendrimer are a promising candidate for the delivery of siRNA into cancer cells in further in vivo studies.

A novel therapeutic outlook: Classification, applications and challenges of inhalable micron/nanoparticle drug delivery systems in lung cancer (Review)

Lung cancer represents a marked global public health concern. Despite existing treatment modalities, the average 5‑year survival rate for patients with patients with lung cancer is only ~20%. As there are numerous adverse effects of systemic administration routes, there is an urgent need to develop a novel therapeutic strategy tailored specifically for patients with lung cancer. Non‑invasive aerosol inhalation, as a route of drug administration, holds unique advantages in the context of respiratory diseases. Nanoscale materials have extensive applications in the field of biomedical research in recent years. The present study provides a comprehensive review of the classification, applications summarized according to existing clinical treatment modalities for lung cancer and challenges associated with inhalable micron/nanoparticle drug delivery systems (DDSs) in lung cancer. Achieving localized treatment of lung cancer preclinical models through inhalation is deemed feasible. However, further research is required to substantiate the efficacy and long‑term safety of inhalable micron/nanoparticle DDSs in the clinical management of lung cancer.

Pulmonary inhalation for disease treatment: Basic research and clinical translations

Pulmonary drug delivery has the advantages of being rapid, efficient, and well-targeted, with few systemic side effects. In addition, it is non-invasive and has good patient compliance, making it a highly promising drug delivery mode. However, there have been limited studies on drug delivery via pulmonary inhalation compared with oral and intravenous modes. This paper summarizes the basic research and clinical translation of pulmonary inhalation drug delivery for the treatment of diseases and provides insights into the latest advances in pulmonary drug delivery. The paper discusses the processing methods for pulmonary drug delivery, drug carriers (with a focus on various types of nanoparticles), delivery devices, and applications in pulmonary diseases and treatment of systemic diseases (e.g., COVID-19, inhaled vaccines, diagnosis of the diseases, and diabetes mellitus) with an updated summary of recent research advances. Furthermore, this paper describes the applications and recent progress in pulmonary drug delivery for lung diseases and expands the use of pulmonary drugs for other systemic diseases.

Erlotinib-Loaded Dendrimer Nanocomposites as a Targeted Lung Cancer Chemotherapy

Lung cancer is the main cause of cancer-related mortality globally. Erlotinib is a tyrosine kinase inhibitor, affecting both cancerous cell proliferation and survival. The emergence of oncological nanotechnology has provided a novel drug delivery system for erlotinib. The aims of this current investigation were to formulate two different polyamidoamine (PAMAM) dendrimer generations-generation 4 (G4) and generation 5 (G5) PAMAM dendrimer-to study the impact of two different PAMAM dendrimer formulations on entrapment by drug loading and encapsulation efficiency tests; to assess various characterizations, including particle size distribution, polydispersity index, and zeta potential; and to evaluate in vitro drug release along with assessing in situ human lung adenocarcinoma cell culture. The results showed that the average particle size of G4 and G5 nanocomposites were 200 nm and 224.8 nm, with polydispersity index values of 0.05 and 0.300, zeta potential values of 11.54 and 4.26 mV of G4 and G5 PAMAM dendrimer, respectively. Comparative in situ study showed that cationic G4 erlotinib-loaded dendrimer was more selective and had higher antiproliferation activity against A549 lung cells compared to neutral G5 erlotinib-loaded dendrimers and erlotinib alone. These conclusions highlight the potential effect of cationic G4 dendrimer as a targeting-sustained-release carrier for erlotinib.

Biocompatible Macroion/Growth Factor Assemblies for Medical Applications

Growth factors are a class of proteins that play a role in the proliferation (the increase in the number of cells resulting from cell division) and differentiation (when a cell undergoes changes in gene expression becoming a more specific type of cell) of cells. They can have both positive (accelerating the normal healing process) and negative effects (causing cancer) on disease progression and have potential applications in gene therapy and wound healing. However, their short half-life, low stability, and susceptibility to degradation by enzymes at body temperature make them easily degradable in vivo. To improve their effectiveness and stability, growth factors require carriers for delivery that protect them from heat, pH changes, and proteolysis. These carriers should also be able to deliver the growth factors to their intended destination. This review focuses on the current scientific literature concerning the physicochemical properties (such as biocompatibility, high affinity for binding growth factors, improved bioactivity and stability of the growth factors, protection from heat, pH changes or appropriate electric charge for growth factor attachment via electrostatic interactions) of macroions, growth factors, and macroion-growth factor assemblies, as well as their potential uses in medicine (e.g., diabetic wound healing, tissue regeneration, and cancer therapy). Specific attention is given to three types of growth factors: vascular endothelial growth factors, human fibroblast growth factors, and neurotrophins, as well as selected biocompatible synthetic macroions (obtained through standard polymerization techniques) and polysaccharides (natural macroions composed of repeating monomeric units of monosaccharides). Understanding the mechanisms by which growth factors bind to potential carriers could lead to more effective delivery methods for these proteins, which are of significant interest in the diagnosis and treatment of neurodegenerative and civilization diseases, as well as in the healing of chronic wounds.

Mechanisms and challenges of nanocarriers as non-viral vectors of therapeutic genes for enhanced pulmonary delivery

With the rapid development of biopharmaceuticals and the outbreak of COVID-19, the world has ushered in a frenzy to develop gene therapy. Therefore, therapeutic genes have received enormous attention. However, due to the extreme instability and low intracellular gene expression of naked genes, specific vectors are required. Viral vectors are widely used attributed to their high transfection efficiency. However, due to the safety concerns of viral vectors, nanotechnology-based non-viral vectors have attracted extensive investigation. Still, issues of low transfection efficiency and poor tissue targeting of non-viral vectors need to be addressed. Especially, pulmonary gene delivery has obvious advantages for the treatment of inherited lung diseases, lung cancer, and viral pneumonia, which can not only enhance lung targeting and but also reduce enzymatic degradation. For systemic diseases therapy, pulmonary gene delivery can enhance vaccine efficacy via inducing not only cellular, humoral immunity but also mucosal immunity. This review provides a comprehensive overview of nanocarriers as non-viral vectors of therapeutic genes for enhanced pulmonary delivery. First of all, the characteristics and therapeutic mechanism of DNA, mRNA, and siRNA are provided. Thereafter, the advantages and challenges of pulmonary gene delivery in exerting local and systemic effects are discussed. Then, the inhalation dosage forms for nanoparticle-based drug delivery systems are introduced. Moreover, a series of materials used as nanocarriers for pulmonary gene delivery are presented, and the endosomal escape mechanisms of nanocarriers based on different materials are explored. The application of various non-viral vectors for pulmonary gene delivery are summarized in detail, with the perspectives of nano-vectors for pulmonary gene delivery.

Recent Advances in Nanomaterials for Asthma Treatment

Asthma is a chronic airway inflammatory disease with complex mechanisms, and these patients often encounter difficulties in their treatment course due to the heterogeneity of the disease. Currently, clinical treatments for asthma are mainly based on glucocorticoid-based combination drug therapy; however, glucocorticoid resistance and multiple side effects, as well as the occurrence of poor drug delivery, require the development of more promising treatments. Nanotechnology is an emerging technology that has been extensively researched in the medical field. Several studies have shown that drug delivery systems could significantly improve the targeting, reduce toxicity and improve the bioavailability of drugs. The use of multiple nanoparticle delivery strategies could improve the therapeutic efficacy of drugs compared to traditional delivery methods. Herein, the authors presented the mechanisms of asthma development and current therapeutic methods. Furthermore, the design and synthesis of different types of nanomaterials and micromaterials for asthma therapy are reviewed, including polymetric nanomaterials, solid lipid nanomaterials, cell membranes-based nanomaterials, and metal nanomaterials. Finally, the challenges and future perspectives of these nanomaterials are discussed to provide guidance for further research directions and hopefully promote the clinical application of nanotherapeutics in asthma treatment.

Potential of Nanotechnology-based Formulations in Combating Pulmonary Infectious Diseases: A Current Scenario

BACKGROUND

Pulmonary microbial infection is mainly caused by microbes like atypical bacteria, viruses, and fungi, on both the upper and lower respiratory tracts. One of the demands of the present is the use of nanotechnology-based treatments to fight various lung infections.

AIM

The main aim of the study is to explore all pulmonary infectious diseases and to compare the advanced and novel treatment approaches with the conventional methods which are available to treat infections.

METHODS

This work sheds light on pulmonary infectious diseases with their conventional and present treatment approaches along with a focus on the advantageous roles of nano-based formulations. In the literature, it has been reported that the respiratory system is the key target of various infectious diseases which gives rise to various challenges in the treatment of pulmonary infections.

RESULTS

The present review article describes the global situation of pulmonary infections and the different strategies which are available for their management, along with their limitations. The article also highlights the advantages and different examples of nanoformulations currently combating the limitations of conventional therapies.

CONCLUSION

The content of the present article further reflects on the summary of recently published research and review works on pulmonary infections, conventional methods of treatment with their limitations, and the role of nano-based approaches to combat the existing infectious diseases which will jointly help the researchers to produce effective drug formulations with desired pharmacological activities.

Nanocarrier-based approaches to combat chronic obstructive pulmonary disease

Abnormalities in airway mucus lead to chronic disorders in the pulmonary system such as asthma, fibrosis and chronic obstructive pulmonary disease (COPD). Among these, COPD is more prominent worldwide. Various conventional approaches are available in the market for the treatment of COPD, but the delivery of drugs to the target site remains a challenge with conventional approaches. Nanocarrier-based approaches are considered the best due to their sustained release properties to the target site, smaller size, high surface-to-volume ratio, patient compliance, overcoming airway defenses and improved pharmacotherapy. This article provides updated information about the treatment of COPD along with nanocarrier-based approaches as well as the potential of gene therapy and stem cell therapy to combat the COPD.

Progress in non-viral localized delivery of siRNA therapeutics for pulmonary diseases

Emerging therapies based on localized delivery of siRNA to lungs have opened up exciting possibilities for treatment of different lung diseases. Localized delivery of siRNA to lungs has shown to result in severalfold higher lung accumulation than systemic route, while minimizing non-specific distribution in other organs. However, to date, only 2 clinical trials have explored localized delivery of siRNA for pulmonary diseases. Here we systematically reviewed recent advances in the field of pulmonary delivery of siRNA using non-viral approaches. We firstly introduce the routes of local administration and analyze the anatomical and physiological barriers towards effective local delivery of siRNA in lungs. We then discuss current progress in pulmonary delivery of siRNA for respiratory tract infections, chronic obstructive pulmonary diseases, acute lung injury, and lung cancer, list outstanding questions, and highlight directions for future research. We expect this review to provide a comprehensive understanding of current advances in pulmonary delivery of siRNA.

Research Progress in Exosome-Based Nanoscale Drug Carriers in Tumor Therapies

Current antitumor treatment methods have several reported limitations, including multidrug resistance and serious adverse reactions. Targeted drug delivery systems are effective alternatives that can help healthcare providers overcome these limitations. Exosomes can serve as a natural nanoscale drug delivery system, with the advantages of high biocompatibility, low immunogenicity, and efficient tumor targetability. In this paper, we discuss the biological characteristics of exosomes, summarize the drug-carrying mechanisms of exosome-based drug delivery systems, and examine the potential role and applicability of exosomes in clinical tumor treatment approaches. This review can be used as a guideline for the future development of exosome-based delivery systems in clinical precision tumor treatment.

Dendrimers as nanoscale vectors: Unlocking the bars of cancer therapy

Chemotherapy is the first choice in the treatment of cancer and is always preferred to other approaches such as radiation and surgery, but it has never met the need of patients for a safe and effective drug. Therefore, new advances in cancer treatment are now needed to reduce the side effects and burdens associated with chemotherapy for cancer patients. Targeted treatment using nanotechnology are now being actively explored as they could effectively deliver therapeutic agents to tumor cells without affecting normal cells. Dendrimers are promising nanocarriers with distinct physiochemical properties that have received considerable attention in cancer therapy studies, which is partly due to the numerous functional groups on their surface. In this review, we discuss the progress of different types of dendrimers as delivery systems in cancer therapy, focusing on the challenges, opportunities, and functionalities of the polymeric molecules. The paper also reviews the various role of dendrimers in their entry into cells via endocytosis, as well as the molecular and inflammatory pathways in cancer. In addition, various dendrimers-based drug delivery (e.g., pH-responsive, enzyme-responsive, redox-responsive, thermo-responsive, etc.) and lipid-, amino acid-, polymer- and nanoparticle-based modifications for gene delivery, as well as co-delivery of drugs and genes in cancer therapy with dendrimers, are presented. Finally, biosafety concerns and issues hindering the transition of dendrimers from research to the clinic are discussed to shed light on their clinical applications.

Inhaled siRNA Formulations for Respiratory Diseases: From Basic Research to Clinical Application

The development of siRNA technology has provided new opportunities for gene-specific inhibition and knockdown, as well as new ideas for the treatment of disease. Four siRNA drugs have already been approved for marketing. However, the instability of siRNA in vivo makes systemic delivery ineffective. Inhaled siRNA formulations can deliver drugs directly to the lung, showing great potential for treating respiratory diseases. The clinical applications of inhaled siRNA formulations still face challenges because effective delivery of siRNA to the lung requires overcoming the pulmonary and cellular barriers. This paper reviews the research progress for siRNA inhalation formulations for the treatment of various respiratory diseases and summarizes the chemical structural modifications and the various delivery systems for siRNA. Finally, we conclude the latest clinical application research for inhaled siRNA formulations and discuss the potential difficulty in efficient clinical application.

Nanotechnology-Assisted Metered-Dose Inhalers (MDIs) for High-Performance Pulmonary Drug Delivery Applications

PURPOSE

Respiratory disorders pose a major threat to the morbidity and mortality to public health. Here we reviewed the nanotechnology based pulmonary drug delivery using metered dose inhalers.

METHODS

Major respiratory diseases such as chronic obstructive pulmonary diseases (COPD), asthma, acute lower respiratory tract infections, tuberculosis (TB) and lung cancer. At present, common treatments for respiratory disorders include surgery, radiation, immunotherapy, and chemotherapy or a combination. The major challenge is development of systemic delivery of the chemotherapeutic agents to the respiratory system. Conventional delivery of chemotherapy has various limitation and adverse side effected. Hence, targeted, and systemic delivery need to be developed. Towards this direction nanotechnology, based controlled, targeted, and systemic drug delivery systems are potential candidate to enhance therapeutic efficacy with minimum side effect. Among different route of administration, pulmonary delivery has unique benefits such as circumvents first pass hepatic metabolism and reduces dose and side effects.

RESULTS

Respiratory disorders pose a major threat to the morbidity and mortality to public health globally. Pulmonary delivery can be achieved through various drug delivery devices such as nebulizers, dry powder inhalers, and metered dose inhalers. Among them, metered dose inhalers are the most interesting and first choice of clinician over others. This review focused on nanotechnology based pulmonary drug delivery using metered dose inhalers. This report focused on delivery of various types of therapeutics using nanocarriers such as polymeric nanoparticles and micelles, dendrimers, lipid nanocarriers such as liposomes, solid lipid nanostructures and nanostructured lipid carriers, and other using metered dose inhalers discussed comprehensively. This report provides insight about the effect of parameters of MDI such as co-solvent, propellants, actuators shape, nozzle diameters, and jet lengths, and respiratory flow rate, and particle size of co-suspension of drug on aerodynamics and lung deposition of formulation. This review also provided the insight about various metered dose inhalers market scenario and digital metered dose inhalers.

CONCLUSION

This report concluded the clinical potential of metered dose inhalers, summary of current progress and future perspectives towards the smart digital metered dose inhalers development.

Immune Repertoire and Advancements in Nanotherapeutics for the Impediment of Severe Steroid Resistant Asthma (SSR)

Severe steroid-resistant asthma (SSR) patients do not respond to the corticosteroid therapies due to the heterogeneity, and genome-wide variations. However, there are very limited reports pertinent to the molecular signaling underlying SSR and making pharmacologists, and formulation scientists to identify the effective therapeutic targets in order to produce novel therapies using novel drug delivery systems (NDDS). We have substantially searched literature for the peer-reviewed and published reports delineating the role of glucocorticoid-altered gene expression, and the mechanisms responsible for SSR asthma, and NDDS for treating SSR asthma using public databases PubMed, National Library of Medicine (NLM), google scholar, and medline. Subsequently, we described reports underlying the SSR pathophysiology through several immunological and inflammatory phenotypes. Furthermore, various therapeutic strategies and the role of signaling pathways such as mORC1-STAT3-FGFBP1, NLRP3 inflammasomes, miR-21/PI3K/HDAC2 axis, PI3K were delineated and these can be considered as the therapeutic targets for mitigating the pathophysiology of SSR asthma. Finally, the possibility of nanomedicine-based formulation and their applications in order to enhance the long term retention of several antioxidant and anti-asthmatic drug molecules as a significant therapeutic modality against SSR asthma was described vividly.

Antisense technology as a potential strategy for the treatment of coronaviruses infection: With focus on COVID-19

After the outbreak of coronavirus disease 2019 (COVID-19) in December 2019 and the increasing number of SARS-CoV-2 infections all over the world, researchers are struggling to investigate effective therapeutic strategies for the treatment of this infection. Targeting viral small molecules that are involved in the process of infection is a promising strategy. Since many host factors are also used by SARS-CoV-2 during various stages of infection, down-regulating or silencing these factors can serve as an effective therapeutic tool. Several nucleic acid-based technologies including short interfering RNAs, antisense oligonucleotides, aptamers, DNAzymes, and ribozymes have been suggested for the control of SARS-CoV-2 as well as other respiratory viruses. The antisense technology also plays an indispensable role in the treatment of many other diseases including cancer, influenza, and acquired immunodeficiency syndrome. In this review, we summarised the potential applications of antisense technology for the treatment of coronaviruses and specifically COVID-19 infection.

Treating Pulmonary Fibrosis with Non-Viral Gene Therapy: From Bench to Bedside

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease characterized by irreversible lung scarring, which achieves almost 80% five-year mortality rate. Undeniably, commercially available pharmaceuticals, such as pirfenidone and nintedanib, exhibit certain effects on improving the well-being of IPF patients, but the stubbornly high mortality still indicates a great urgency of developing superior therapeutics against this devastating disease. As an emerging strategy, gene therapy brings hope for the treatment of IPF by precisely regulating the expression of specific genes. However, traditional administration approaches based on viruses severely restrict the clinical application of gene therapy. Nowadays, non-viral vectors are raised as potential strategies for in vivo gene delivery, attributed to their low immunogenicity and excellent biocompatibility. Herein, we highlight a variety of non-viral vectors, such as liposomes, polymers, and proteins/peptides, which are employed in the treatment of IPF. By respectively clarifying the strengths and weaknesses of the above candidates, we would like to summarize the requisite features of vectors for PF gene therapy and provide novel perspectives on design-decisions of the subsequent vectors, hoping to accelerate the bench-to-bedside pace of non-viral gene therapy for IPF in clinical setting.

Emerging trends in pulmonary delivery of biopharmaceuticals

Over the years, a tendency toward biopharmaceutical products as therapeutics has been witnessed compared with small molecular drugs. Biopharmaceuticals possess greater specificity, selectivity and potency with fewer side effects. The pulmonary route is a potential noninvasive route studied for the delivery of various molecules, including biopharmaceuticals. It directly delivers drugs to the lungs in higher concentrations and provides greater bioavailability than other noninvasive routes. This review focuses on the pulmonary route for the delivery of biopharmaceuticals. We have covered various biopharmaceuticals, including peptides, recombinant proteins, enzymes, monoclonal antibodies and nucleic acids, administered via a pulmonary route and discussed their rewards and drawbacks.

Synthesis and bioactivity of readily hydrolysable novel cationic lipids for potential lung delivery application of mRNAs

Lipid nanoparticles (LNPs) mediated mRNA delivery has gained prominence due to the success of mRNA vaccines against Covid-19, without which it would not have been possible. However, there is little clinical validation of this technology for other mRNA-based therapeutic approaches. Systemic administration of LNPs predominantly targets the liver, but delivery to other organs remains a challenge. Local approaches remain a viable option for some disease indications, such as Cystic Fibrosis, where aerosolized delivery to airway epithelium is the preferred route of administration. With this in mind, novel cationic lipids (L1-L4) have been designed, synthesized and co-formulated with a proprietary ionizable lipid. These LNPs were further nebulized, along with baseline control DOTAP-based LNP (DOTAP⁺), and tested in vitro for mRNA integrity and encapsulation efficiency, as well as transfection efficiency and cytotoxicity in cell cultures. Improved biodegradability and potentially superior elimination profiles of L1-L4, in part due to physicochemical characteristics of putative metabolites, are thought to be advantageous for prospective therapeutic lung delivery applications using these lipids.

Dendriplex-Impregnated Hydrogels With Programmed Release Rate

Hydrogels are biocompatible matrices for local delivery of nucleic acids; however, functional dopants are required to provide efficient delivery into cells. In particular, dendrimers, known as robust nucleic acid carriers, can be used as dopants. Herein, we report the first example of impregnating neutral hydrogels with siRNA-dendrimer complexes. The surface chemistry of dendrimers allows adjusting the release rate of siRNA-containing complexes. This methodology can bring new materials for biomedical applications.

Microemulsion Based Nanostructures for Drug Delivery

Most of the active pharmaceutical compounds are often prone to display low bioavailability and biological degradation represents an important drawback. Due to the above, the development of a drug delivery system (DDS) that enables the introduction of a pharmaceutical compound through the body to achieve a therapeutic effect in a controlled manner is an expanding application. Henceforth, new strategies have been developed to control several parameters considered essential for enhancing delivery of drugs. Nanostructure synthesis by microemulsions (ME) consist of enclosing a substance within a wall material at the nanoscale level, allowing to control the size and surface area of the resulting particle. This nanotechnology has shown the importance on targeted drug delivery to improve their stability by protecting a bioactive compound from an adverse environment, enhanced bioavailability as well as controlled release. Thus, a lower dose administration could be achieved by minimizing systemic side effects and decreasing toxicity. This review will focus on describing the different biocompatible nanostructures synthesized by ME as controlled DDS for therapeutic purposes.

Nanoparticles for local delivery of siRNA in lung therapy

An overview of the application of natural and synthetic, non-viral vectors for oligonucleotide delivery into the lung is presented in this review, with a special focus on lung cancer. Due to the specificity of the respiratory tract, its structure and natural barriers, the administration of drugs (especially those based on nucleic acids) is a particular challenge. Among widely tested non-viral drug and oligonucleotides carriers, synthetic polymers seem to be most promising. Unique properties of these nanoparticles allow for essentially unlimited possibilities regarding their design and modification. This gives hope that optimal nanoparticles with ideal nucleic acid carrier properties for lung cancer therapy will eventually emanate.

Efficient and safe small RNA delivery to macrophage using peptide-based nanocomplex

As one of the gene therapies, RNA interference (RNAi) effectively suppresses only specific genes, targeting various diseases in which they are involved. For the successful process of RNAi, efficient and safe delivery of small RNAs, including small interfering RNA and short hairpin RNA, is essential. Herein, an S-R11 fusion peptide, SPACE peptide conjugated with poly-arginine, was introduced to deliver small RNAs into immune cells that are difficult to transfect. This S-R11 peptide stably formed a spontaneous self-assembling nanocomplex through electrostatic attraction and hydrogen bonding with small RNAs. The nanocomplex showed about 5.3-fold better permeation efficiency than the conventional Lipofectamine™ 2000 for RAW 264.7 macrophage cells. Moreover, it induced about 66.2% silencing effect of the target gene in the cells activated with polyinosinic:polycytidylic acid (poly (I:C)). In addition, the cell viability of fusion peptide was ensured even in a concentration range exceeding the concentration used in the nanocomplex. Based on these results, it is expected that the nanocomplex in this study can be used as a new gene delivery system that can overcome the challenge of gene therapies to immune cells.

Therapeutic perceptions in antisense RNA-mediated gene regulation for COVID-19

COVID-19 was first reported in Wuhan, China, in December 2019. It is widely accepted that the world will not return to its prepandemic normality until safe and effective vaccines are available and a global vaccination program has been successfully implemented. Antisense RNAs are single-stranded RNAs that occur naturally or are synthetic and enable hybridizing and protein-blocking translation. Therefore, the main objective of this study was to identify target markers in the RNA of the severe acute respiratory syndrome coronavirus, or SARS-CoV-2, with a length between 21 and 28 bases that could enable the development of vaccines and therapies based on antisense RNA. We used a search algorithm in C language to compare 3159 complete nucleotide sequences from SARS-CoV-2 downloaded from the repository of the National Center for Biotechnology Information. The objective was to verify whether any common sequences were present in all 3159 strains of SARS-CoV-2. In the first of three datasets (SARS-CoV-2), the algorithm found two sequences each of 21 nucleotides (Sequence 1: CTACTGAAGCCTTTGAAAAAA; Sequence 2: TGTGGTTATACCTACTAAAAA). In the second dataset (SARS-CoV) and third dataset (MERS-CoV), no sequences of size N between 21 and 28 were found. Sequence 1 and Sequence 2 were input into BLAST® ≫ blastn and recognized by the platform. The gene identified by the sequences found by the algorithm was the ORF1ab region of SARS-CoV-2. Considerable progress in antisense RNA research has been made in recent years, and great achievements in the application of antisense RNA have been observed. However, many mechanisms of antisense RNA are not yet understood. Thus, more time and money must be invested into the development of therapies for gene regulation mediated by antisense RNA to treat COVID-19 as no effective therapy for this disease has yet been found.

Toward the prevention of coronavirus infection: what role can polymers play?

Severe acute respiratory syndrome-associated coronavirus 2 has caused a global public health crisis with high rates of infection and mortality. Treatment and prevention approaches include vaccine development, the design of small-molecule antiviral drugs, and macromolecular neutralizing antibodies. Polymers have been designed for effective virus inhibition and as antiviral drug delivery carriers. This review summarizes recent progress and provides a perspective on polymer-based approaches for the treatment and prevention of coronavirus infection. These polymer-based partners include polyanion/polycations, dendritic polymers, macromolecular prodrugs, and polymeric drug delivery systems that have the potential to significantly improve the efficacy of antiviral therapeutics.

Application of nanotechnology in drug delivery systems for respiratory diseases (Review)

Respiratory disease is a common disease with a high incidence worldwide, which is a serious threat to human health, and is considered a societal and economic burden. The application of nanotechnology in drug delivery systems has created new treatments for respiratory diseases. Within this context, the present review systematically introduced the physicochemical properties of nanoparticles (NPs); reviewed the current research status of different nanocarriers in the treatment of respiratory diseases, including liposomes, solid lipid nanocarriers, polymeric nanocarriers, dendrimers, inorganic nanocarriers and protein nanocarriers; and discussed the main advantages and limitations of therapeutic nanomedicine in this field. The application of nanotechnology overcomes drug inherent deficiencies to a certain extent, and provides unlimited potential for the development of drugs to treat respiratory diseases. However, most of the related research work is in the preclinical experimental stage and safety assessment is still a challenging task. Future studies are needed to focus on the performance modification, molecular mechanism and potential toxicity of therapeutic nanomedicine.

RNAi Technology and Investigation on Possible Vaccines to Combat SARS-CoV-2 Infection

Coronavirus disease of 2019 (COVID-19) pandemic, taking place globally, occurs as a result of the SARS-CoV-2 viral infection which has caused death of innumerable numbers of people and is responsible for a massive drop in the global economy. Millions of people are infected, and the death rate is also quite high in different countries. So, there is an urgent requirement of the invention of some effective and efficient drugs that can be effective against this deadly viral infection. The invention of new drugs and vaccine has become a matter of utmost importance to stop the mayhem of coronavirus pandemic. In the middle of such a deadly pandemic, the necessity of development of a vaccine is of high importance in this context. Among all the popular methods of vaccine development, the mRNA vaccines turned out to be the one of the most versatile vaccine with quick responses. However, in this review, we have explained all the possible types of vaccines available including DNA vaccines, RNA vaccines, and live and attenuated vaccines. Their effectiveness, importance, and application of the vaccines against the SARS-CoV-2 virus have been discussed. Research is also being conducted in the field of gene silencing, and one of the best possible ways to combat the virus at the molecular level is by applying RNAi technology. The modified siRNA molecules can be used to silence the gene expression of the virus. A summarization of the virus’s behavior, characteristics, and the methods by which RNAi technology can be administered to control the virus is depicted in this study.

Pulmonary siRNA delivery for lung disease: Review of recent progress and challenges

Lung diseases are a leading cause of mortality worldwide and there exists urgent need for new therapies. Approval of the first siRNA treatments in humans has opened the door for further exploration of this therapeutic strategy for other disease states. Pulmonary delivery of siRNA-based biopharmaceuticals offers the potential to address multiple unmet medical needs in lung-related diseases because of the specific physiology of the lung and characteristic properties of siRNA. Inhalation-based siRNA delivery designed for efficient, targeted delivery to specific cells within the lung holds great promise. Efficient delivery of siRNA directly to the lung, however, is relatively complex. This review focuses on the barriers that impact pulmonary siRNA delivery and successful recent approaches to advance this field forward. We focus on the pulmonary barriers that affect siRNA delivery, the disease-dependent pathological changes and their role in pulmonary disease and impact on siRNA delivery, as well as the recent development on the pulmonary siRNA delivery systems.

Emerging therapeutics in the management of COVID-19

The severe acute respiratory syndrome coronavirus 2 (coronavirus disease 2019, COVID-19) pandemic has placed a tremendous burden on healthcare systems globally. Therapeutics for treatment of the virus are extremely inconsistent due to the lack of time evaluating drug efficacy in clinical trials. Currently, there is a deficiency of published literature that comprehensively discusses all therapeutics being considered for the treatment of COVID-19. A review of the literature was performed for articles related to therapeutics and clinical trials in the context of the current COVID-19 pandemic. We used PubMed, Google Scholar, and Clinicaltrials.gov to search for articles relative to the topic of interest. We used the following keywords: "COVID-19", "therapeutics", "clinical trials", "treatment", "FDA", "ICU", "mortality", and "management". In addition, searches through the references of retrieved articles was also performed. In this paper, we have elaborated on the therapeutic strategies that have been hypothesized or trialed to-date, the mechanism of action of each therapeutic, the clinical trials finished or in-process that support the use of each therapeutic, and the adverse effects associated with each therapeutic. Currently, there is no treatment that has been proven to provide significant benefit in reducing morbidity and mortality. There are many clinical trials for numerous different therapeutic agents currently underway. By looking back and measuring successful strategies from previous pandemics in addition to carrying out ongoing research, we provide ourselves with the greatest opportunity to find treatments that are beneficial.

The pH-Responsive Property of Antimicrobial Peptide GH12 Enhances Its Anticaries Effects at Acidic pH

Dental caries is closely related to the acidification of the biofilms on the tooth surface, in which cariogenic bacteria bring about a dramatic pH decrease and disrupt remineralisation equilibrium upon the fermentation of dietary sugars. Thus, approaches targeting the acidified niches with enhanced anticaries activities at acidic pH are highly desirable. In our previous study, a cationic amphipathic α-helical antimicrobial peptide GH12 (Gly-Leu-Leu-Trp-His-Leu-Leu-His-His-Leu-Leu-His-NH2) was designed with good stability, low cytotoxicity, and excellent antibacterial effects. Considering its potent antibacterial activity against the acidogenic bacteria and its histidine-rich sequence, it was speculated that GH12 might show enhanced antimicrobial effects at an acidic pH. In this study, the pH-responsive property of GH12 was determined to evaluate its potential as a smart acid-activated anticaries agent. GH12 possessed much lower minimal inhibitory concentrations and minimal bactericidal concentrations against various kinds of bacteria at pH 5.5 than at pH 7.2. Employing Streptococcus mutans, the principal caries pathogen, as the model system, it was found that GH12 showed much stronger bactericidal effects on both planktonic S. mutans and S. mutans embedded in the biofilm at pH 5.5. In addition, short-term treatment with GH12 showed much more effective inhibitory effects on water-insoluble exopolysaccharides synthesis and lactic acid production of the preformed S. mutans biofilm at pH 5.5. As for the mechanism exploration, it was found that the net positive charge of GH12 increased and the tryptophan fluorescence intensity heightened with the peak shifting towards the short wavelength at pH 5.5, which demonstrated that GH12 could be more easily attracted to the anionic microbial cell membranes and that GH12 showed stronger interactions with the lipid membranes. In conclusion, acidic pH enhanced the antibacterial and antibiofilm activities of GH12, and GH12 is a potential smart anticaries agent targeting the cariogenic acidic microenvironment.

Novel drug delivery systems targeting oxidative stress in chronic obstructive pulmonary disease: a review

Oxidative stress is significantly involved in the pathogenesis and progression of chronic obstructive pulmonary disease (COPD). Combining antioxidant drugs or nutrients results in a noteworthy therapeutic value in animal models of COPD. However, the benefits have not been reproduced in clinical applications, this may be attributed to the limited absorption, concentration, and half-life of exogenous antioxidants. Therefore, novel drug delivery systems to combat oxidative stress in COPD are needed. This review presents a brief insight into the current knowledge on the role of oxidative stress and highlights the recent trends in novel drug delivery carriers that could aid in combating oxidative stress in COPD. The introduction of nanotechnology has enabled researchers to overcome several problems and improve the pharmacokinetics and bioavailability of drugs. Large porous microparticles, and porous nanoparticle-encapsulated microparticles are the most promising carriers for achieving effective pulmonary deposition of inhaled medication and obtaining controlled drug release. However, translating drug delivery systems for administration in pulmonary clinical settings is still in its initial phases.

Pharmacokinetics of inhaled nanotherapeutics for pulmonary delivery

Pulmonary delivery of lipid-based nanotherapeutics by inhalation presents an advantageous alternative to oral and intravenous routes of administration that avoids enzymatic degradation in gastrointestinal tract and hepatic first pass metabolism and also limits off-target adverse side effects upon heathy tissues. For lung-related indications, inhalation provides localized delivery in order to enhance therapeutic efficacy at the site of action. Optimization of physicochemical properties, selected drug and inhalation format can greatly influence the pharmacokinetic behavior of inhaled nanoparticle systems and their payloads. The present review analyzes a wide range of nanoparticle systems, their formulations and consequent effect on pharmacokinetic distribution of delivered active components after inhalation.

Nanocarriers in effective pulmonary delivery of siRNA: current approaches and challenges

Research on siRNA is increasing due to its wide applicability as a therapeutic agent in irreversible medical conditions. siRNA inhibits expression of the specific gene after its delivery from formulation to cytosol region of a cell. RNAi (RNA interference) is a mechanism by which siRNA is silencing gene expression for a particular disease. Numerous studies revealed that naked siRNA delivery is not preferred due to instability and poor pharmacokinetic performance. Nanocarriers based delivery of siRNA has the advantage to overcome physiological barriers and protect the integrity of siRNA from degradation by RNAase. Various diseases like lung cancer, cystic fibrosis, asthma, etc can be treated effectively by local lung delivery. The selective targeted therapeutic action in diseased organ and least off targeted cytotoxicity are the key benefits of pulmonary delivery. The current review highlights recent developments in pulmonary delivery of siRNA with novel nanosized formulation approach with the proven in vitro/in vivo applications.

Quantitative comparison of three widely-used pulmonary administration methods in vivo with radiolabeled inhalable nanoparticles

Pulmonary formulations have been attracting much attention because of their direct effects on respiratory diseases, but also their non-invasive administration for the treatment of systemic diseases. When developing such formulations, they are typically first investigated in mice. As there are various pulmonary administration methods, the researcher has to decide on the best quantitative method for their preclinical investigations among candidate methods, both for total delivery and distribution within the lung lobes. In this study, we investigated the deposition and distribution of siRNA loaded PLGA nanoparticles (NPs) in the different lung lobes via three widely used pulmonary administration methods: intratracheal instillation, intratracheal spraying and intranasal instillation. The NPs were radiolabeled with ¹¹¹In, administered and a single photon emission computed tomography (SPECT/CT) whole body scan performed. Quantitative image volume of interest (VOI) analysis of all inhalation related organs was performed, plus sub-organ examinations using dissection and gamma counting. Intratracheal instillation and intratracheal spraying deposited >95% and >85% of radiolabeled NPs in the lung, respectively. However, the lung lobe distribution of the NPs was inhomogeneous. Intranasal instillation deposited only ~28% of the dose in the lungs, with even larger inhomogeneity and individual variation between animals. Furthermore, there was a high deposition of the NPs in the stomach. Intratracheal instillation and intratracheal spraying deposit a large number of NPs in the lungs, and are thus useful to test therapeutic effects in preclinical animal studies. However, the inhomogeneous distribution of formulation between lung lobes needs to be considered in the experimental design. Intranasal instillation should not be used as a means of pulmonary administration.

Dendrimer Conjugation Enhances Tumor Penetration and Efficacy of Doxorubicin in Extracellular Matrix-Expressing 3D Lung Cancer Models

Doxorubicin (DOX) is a chemotherapeutic agent broadly used in the treatment of a range of solid tumors. In spite of its high potency, as is the case for many other chemotherapeutic drugs, there are many challenges associated with the use of DOX in clinical oncology. This is particularly true for DOX in the treatment of lung cancer, where in vitro potency is shown to be very high, but low lung distribution and off-target toxicity (particularly cardiotoxicity) restrict its use. Nanocarrier-based drug delivery systems (nanoDDS) have been shown to help alter biodistribution and alleviate off-target toxicity associated with DOX. While significant understanding exists regarding the design parameters to achieve those clinical benefits, much less is known regarding the design of nanoDDS capable of enhancing tumor penetration of DOX (and other drugs), which is another major factor leading to DOX's reduced efficacy. The purpose of this study was to design a dendrimer-based nanoDDS capable of enhancing the penetration of DOX as measured in an in vitro 3D lung tumor model and to correlate those results with its efficacy. Spheroids formed with the A549 human lung adenocarcinoma cells/murine fibroblast cell line (NIH/3T3 cell line) are shown to produce the essential components of the extracellular matrix (ECM), which is known as a physical barrier that hinders the transport of DOX. DOX was conjugated to generation 4 succinamic acid-terminated poly(amido-amine) (PAMAM) dendrimers (G4SA) through an enzyme-liable tetrapeptide (G4SA-GFLG-DOX), resulting in a nanoDDS with ∼5.5 DOX, -17 mV surface (ζ) potential, and a 10 nm hydrodynamic diameter (HD). The penetration of DOX to the core of the spheroid in terms of DOX fluorescence was determined to be 3.1-fold greater compared to free DOX, which positively correlated with enhanced efficacy as measured by the Caspase 3/7 assay. This improved penetration happens as the interactions between the G4SA-GFLG-DOX and the highly negatively charged ECM are minimized by shielding the protonatable amine of DOX upon conjugation, and the HD of the conjugate is kept smaller than the estimated mesh size of the ECM. Interestingly, the conjugate provided more specificity for DOX to tumor cells compared to fibroblasts, while free DOX is equally distributed in both tumor and fibroblasts as assessed in the coculture spheroids. Growth inhibition studies show that the released DOX maintains its activity and leads to tumor reduction to the same extent as free DOX. The results obtained here are of relevance for the design of dendrimer-based nanoDDS and for the treatment of solid tumors as they provide critical information regarding desirable surface characteristics and sizes for efficient tumor penetration.

Structural changes in lipid mesophases due to intercalation of dendritic polymer nanoparticles: Swollen lamellae, suppressed curvature, and augmented structural disorder

Understanding interactions between nanoparticles and model membranes is relevant to functional nano-composites and the fundamentals of nanotoxicity. In this study, the effect of polyamidoamine (PAMAM) dendrimers as model nanoparticles (NP) on the mesophase behaviour of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) has been investigated using high-pressure small-angle X-ray scattering (HP-SAXS). The pressure-temperature (p-T) diagrams for POPE mesophases in excess water were obtained in the absence and presence of G2 and G4 polyamidoamine (PAMAM) dendrimers (29 Å and 45 Å in diameter, respectively) at varying NP-lipid number ratio (ν = 0.0002-0.02) over the pressure range p = 1-3000 bar and temperature range T = 20-80 °C. The p-T phase diagram of POPE exhibited the L_β, L_α and H_II phases. Complete analysis of the phase diagrams, including the relative area pervaded by different phases, phase transition temperatures (T_t) and pressures (p_t), the lattice parameters (d-spacing), the pressure-dependence of d-spacing (Δd/Δp), and the structural ordering in the mesophase as gauged by the Scherrer coherence length (L) permitted insights into the size- and concentration-dependent interactions between the dendrimers and the model membrane system. The addition of dendrimers changed the phase transition pressure and temperature and resulted in the emergence of highly swollen lamellar phases, dubbed L_β-den and L_α-den. G4 PAMAM dendrimers at the highest concentration ν = 0.02 suppressed the formation of the H_II phase within the temperature range studied, whereas the addition of G2 PAMAM dendrimers at the same concentration promoted an extended mixed lamellar region in which L_α and L_β phases coexisted. STATEMENT OF SIGNIFICANCE: Using high pressure small angle X-ray scattering in the pressure range 1-3000 bar and temperature range 20-60 °C, we have studied interactions between PAMAM dendrimers (as model nanoparticles) and POPE lipid mesophases (as model membranes). We report the pressure-temperature phase diagrams for the dendrimer-lipid mesophases for the first time. We find that the dendrimers alter the phase transition temperatures (T_t) and pressures (p_t), the lattice parameters (d-spacing), and the structural order in the mesophase. We interpret these unprecedented results in terms of the fluidity of the lipid membranes and the interactions between the dendrimers and the membranes. Our findings are of fundamental relevance to the field of nanotoxicity and functional nanomaterials that integrate nanoparticles and organized lipid structures.

Nanomedicine Approaches for the Pulmonary Treatment of Cystic Fibrosis

Cystic fibrosis (CF) is a genetic disease affecting today nearly 70,000 patients worldwide and characterized by a hypersecretion of thick mucus difficult to clear arising from the defective CFTR protein. The over-production of the mucus secreted in the lungs, along with its altered composition and consistency, results in airway obstruction that makes the lungs susceptible to recurrent and persistent bacterial infections and endobronchial chronic inflammation, which are considered the primary cause of bronchiectasis, respiratory failure, and consequent death of patients. Despite the difficulty of treating the continuous infections caused by pathogens in CF patients, various strategies focused on the symptomatic therapy have been developed during the last few decades, showing significant positive impact on prognosis. Moreover, nowadays, the discovery of CFTR modulators as well as the development of gene therapy have provided new opportunity to treat CF. However, the lack of effective methods for delivery and especially targeted delivery of therapeutics specifically to lung tissues and cells limits the efficiency of the treatments. Nanomedicine represents an extraordinary opportunity for the improvement of current therapies and for the development of innovative treatment options for CF previously considered hard or impossible to treat. Due to the peculiar environment in which the therapies have to operate characterized by several biological barriers (pulmonary tract, mucus, epithelia, bacterial biofilm) the use of nanotechnologies to improve and enhance drug delivery or gene therapies is an extremely promising way to be pursued. The aim of this review is to revise the currently used treatments and to outline the most recent progresses about the use of nanotechnology for the management of CF.

The influence of different charged poly (amido amine) dendrimer on the transport and deposition of bacteria in porous media

The influence of dendrimer on the bacterial transport and deposition behaviors in saturated porous media (quartz sand) was investigated in both NaCl (10 and 25 mM) and CaCl₂ solutions (1.2 and 5 mM). 3.5G and 4G poly (amido amine) (PAMAM) dendrimer was employed as negatively and positively charged dendrimer, respectively. Three dendrimer concentrations (10 μg/L, 1 and 10 mg/L) were considered in present study. We found that regardless of the solution chemistry (ionic strength and ion types) and dendrimer concentrations, the presence of negatively charged PAMAM 3.5G in suspensions enhanced bacterial transport and inhibited their deposition in quartz sand; while the presence of positive charged PAMAM 4G yet induced the opposite effects (decreased bacterial transport and increased their deposition in quartz sand). The increased repulsive force between cell and quartz sand due to the adsorption of PAMAM 3.5G onto both cell and sand surfaces, the competition deposition sites as well as the steric repulsion via the suspended PAMAM 3.5G drove to the increased bacterial transport with PAMAM 3.5G copresent in suspensions in quartz sand. While the reduced repulsive force between cell and quartz sand induced by the chemical heterogeneity on both cell and sand surfaces (due to the adsorption of positive charged PAMAM 4G) increased bacterial retention in quartz sand with copresence of PAMAM 4G (10 μg/L and 1 mg/L) in suspensions. Steric repulsion due to the presence of great amount of suspended PAMAM 4G yet lead to the enhanced bacterial transport with furthering increasing PAMAM 4G to 10 mg/L relative to the lower PAMAM 4G concentration.

Characterization of spray dried powders with nucleic acid-containing PEI nanoparticles

Localized aerosol delivery of gene therapies is a promising treatment of severe pulmonary diseases including lung cancer, cystic fibrosis, COPD and asthma. The administration of drugs by inhalation features multiple benefits including an enhanced patient acceptability and compliance. The application of a spray dried powder formulation has advantages over solutions due to their increased stability and shelf life. Furthermore, optimal sizes of the powder can be obtained by spray drying to allow a deep lung deposition. The present study optimized the parameters involved with spray drying polyplexes formed by polyethylenimine (PEI) and nucleic acids in inert excipients to generate a nano-embedded microparticle (NEM) powder with appropriate aerodynamic diameter. Furthermore, the effects of the excipient matrix used to generate the NEM powder on the biological activity of the nucleic acid and the ability to recover the embedded nanoparticles was investigated. The study showed that bioactivity and nucleic acid integrity was preserved after spray drying, and that polyplexes could be reconstituted from the dry powders made with trehalose but not mannitol as a stabilizer. Scanning electron microscopy (SEM) showed trehalose formulations that formed fused, lightly corrugated spherical particles in the range between 1 and 5 µm, while mannitol formulations had smooth surfaces and consisted of more defined particles. After redispersion of the microparticles in water, polyplex dispersions are obtained that are comparable to the initial formulations before spray drying. Cellular uptake and transfection studies conducted in lung adenocarcinoma cells show that redispersed trehalose particles performed similar to or better than polyplexes that were not spray dried. A method for quantifying polymer and nucleic acid loss following spray drying was developed in order to ensure that equal nucleic acid amounts were used in all in vitro experiments. The results confirm that spray dried NEM formulations containing nucleic acids can be prepared with characteristics known to be optimal for inhalation therapy.

Formulation of RNA interference-based drugs for pulmonary delivery: challenges and opportunities

With recent advances in the field of RNAi-based therapeutics, it is possible to make any target gene 'druggable', at least in principle. The present review focuses on aspects critical for pulmonary delivery of formulations of nucleic acid-based drugs. The first part introduces the therapeutic potential of RNAi-based drugs for the treatment of lung diseases. Subsequently, we discuss opportunities for formulation-enabled pulmonary delivery of RNAi drugs in light of key physicochemical properties and physiological barriers. In the following section, an overview is included of methodologies for imparting inhalable characteristics to nucleic acid formulations. Finally, we review one of the bottlenecks in the early preclinical testing of inhalable nucleic acid-based formulations, in other words, devices suitable for pulmonary administration of powder-based formulations in rodents.

Oligonucleotide therapy: An emerging focus area for drug delivery in chronic inflammatory respiratory diseases

Oligonucleotide-based therapies are advanced novel interventions used in the management of various respiratory diseases such as asthma and Chronic Obstructive Pulmonary Disease (COPD). These agents primarily act by gene silencing or RNA interference. Better methodologies and techniques are the need of the hour that can deliver these agents to tissues and cells in a target specific manner by which their maximum potential can be reached in the management of chronic inflammatory diseases. Nanoparticles play an important role in the target-specific delivery of drugs. In addition, oligonucleotides also are extensively used for gene transfer in the form of polymeric, liposomal and inorganic carrier materials. Therefore, the current review focuses on various novel dosage forms like nanoparticles, liposomes that can be used efficiently for the delivery of various oligonucleotides such as siRNA and miRNA. We also discuss the future perspectives and targets for oligonucleotides in the management of respiratory diseases.