Inhalable nanoparticulate powders for respiratory delivery

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.

Characteristics of SARS-CoV2 that may be useful for nanoparticle pulmonary drug delivery

As a non-invasive method of local and systemic drug delivery, the administration of active pharmaceutical ingredients (APIs) via the pulmonary route represents an ideal approach for the therapeutic treatment of pulmonary diseases. The pulmonary route provides a number of advantages, including the rapid absorption which results from a high level of vascularisation over a large surface area and the successful avoidance of first-pass metabolism. Aerosolization of nanoparticles (NPs) is presently under extensive investigation and exhibits a high potential for targeted delivery of therapeutic agents for the treatment of a wide range of diseases. NPs need to possess specific characteristics to facilitate their transport along the pulmonary tract and appropriately overcome the barriers presented by the pulmonary system. The most challenging aspect of delivering NP-based drugs via the pulmonary route is developing colloidal systems with the optimal physicochemical parameters for inhalation. The physiochemical properties of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have been investigated as a template for the synthesis of NPs to assist in the formulation of virus-like particles (VLPs) for pharmaceutical delivery, vaccine production and diagnosis assays.

Recent advances in herbal combination nanomedicine for cancer: delivery technology and therapeutic outcomes

Introduction: The use of herbal compounds in cancer therapy has great potential to promote the efficacy of current cancer therapeutic strategies. Herbal compounds were successfully reported to enhance tumor cells sensitization to the action of chemo-, hormonal- and gene-therapeutic agents via different mechanisms. Herbal ingredients can affect different signaling pathways, reduce the toxic side effects or inhibit the efflux of anticancer drugs.Areas covered: This review will discuss the delivery of herbal compounds with other cancer treatments such as hormonal, small molecule inhibitors and inorganic hybrids to tumor cells. An overview of physicochemical properties of herbal components that require intelligent design of combo-nanomedicines for efficient co-delivery of those herbal-derived and other anticancer agents was discussed. Nanocarriers provide various benefits to overcome the shortcomings of the encapsulated herbal compounds including improved solubility, increased stability and enhanced tumor targeting. Different nanocarrier systems were the focus of this review.Expert opinion: Multifunctional nanocarrier systems encapsulating herbal and different anticancer drugs showed to be a wonderful approach in the treatment of cancer enabling the co-delivery of anticancer drugs with versatile modes of action in an accurate manner in an attempt to enhance the efficacy, benefit from the synergism between the drugs as well as to minimize the development of multi-drug resistance. The main challenge point is the early detection and management of any developed adverse effect.

Covalently coupling doxorubicin to polymeric nanoparticles as potential inhaler therapy: in vitro studies

Lung cancer is the most commonly diagnosed type of cancer worldwide, non-small cell lung cancer accounts for most lung cancers. Doxorubicin is a widely used chemotherapy agent in lung cancer. However, the drug has several undesirable side effects. Here, doxorubicin coupled PEGylated mucoadhesive nanoparticles were designed as a doxorubicin delivery system for pH-triggered release in lung cancer therapy through inhaler administration. Firstly, alginate/chitosan nanoparticles were developed at optimum conditions. Then, PEG diacid bound to structures for doxorubicin binding and providing steric hindrance for phagocytosis. Doxorubicin was linked via an acid-labile amide bond to PEGylated nanoparticles and 444.3 ± 9.2 µg doxorubicin was loaded per mg nanoparticle. Doxorubicin coupled PEG diacid linked alginate/chitosan nanoparticles were checked with FTIR. Hydrodynamic diameter and zeta potential of nanoparticles were measured as 205.7 ± 15.0 nm and -25.17 ± 2.67 mV. The morphology of nanoparticles was evaluated as nearly spherical. Drug release studies were performed both in physiological and acidic media. The drug release from nanoparticles reached 23.6% (pH 5.5) and 18% (pH 7.4) within 48 h. The cytotoxicity experiments were done using A549-luc-C8 cells, also statistical analyzes were carried out. The MTT results indicated the designed drug delivery system possessed anti-tumor efficacy for non-small cell lung cancer therapy.

Inhaled antibiotic-loaded polymeric nanoparticles for the management of lower respiratory tract infections

Lower respiratory tract infections (LRTIs) are one of the leading causes of deaths in the world. Currently available treatment for this disease is with high doses of antibiotics which need to be administered frequently. Instead, pulmonary delivery of drugs has been considered as one of the most efficient routes of drug delivery to the targeted areas as it provides rapid onset of action, direct deposition of drugs into the lungs, and better therapeutic effects at low doses and is self-administrable by the patients. Thus, there is a need for scientists to design more convenient pulmonary drug delivery systems towards the innovation of a novel treatment system for LRTIs. Drug-encapsulating polymer nanoparticles have been investigated for lung delivery which could significantly reduce the limitations of the currently available treatment system for LRTIs. However, the selection of an appropriate polymer carrier for the drugs is a critical issue for the successful formulations of inhalable nanoparticles. In this review, the current understanding of LRTIs, management systems for this disease and their limitations, pulmonary drug delivery systems and the challenges of drug delivery through the pulmonary route are discussed. Drug-encapsulating polymer nanoparticles for lung delivery, antibiotics used in pulmonary delivery and drug encapsulation techniques have also been reviewed. A strong emphasis is placed on the impact of drug delivery into the infected lungs.

Optimization of Solid Lipid Nanoparticles and Nanostructured Lipidic Carriers as Promising Delivery for Gefitinib: Characterization and Invitro Evaluation

Background:

Response surface methodology is a unique tool for the optimization of Solid lipid Nanoparticles and Nanostructured lipid carriers by developing the relationship between dependent and independent variables and exploring their interactions.

Methods:

Central Composite Design and Box Benkhen Design was used to develop optimized formulations of Gefitinib [GEF] Solid Lipid Nanoparticles [SLN] and Nanostructured Lipidic Carriers [NLC]. In the design matrix, the independent variables chosen were the amount of Solid Lipid, Liquid Lipid, and Surfactant and dependent variables were Particle Size and Poly Dispersity Index.

Result:

The GEF-SLN under optimized conditions gave rise to Particle size (187.9 nm ± 1.15), PDI (0.318 ± 0.006), %EE (95.38%±0.14), Zeta Potential (-8.75 mv ±0.18) and GEF-NLC under optimized conditions gave rise to Particle size (188.6 nm± 1.12), PDI (0.395± 0.004), %EE (97.46%± 0.33), Zeta Potential (-5.72 mv± 0.04) respectively. SEM of the Freeze-dried optimized lipidic carriers showed spherical particles. The in vitro experiments proved that Gefitinib in the lipidic carriers is released gradually throughout 24 h.

Conclusion:

This study showed that the response surface methodology could be efficiently applied for the modeling of GEF-SLN & GEF-NLC.

Intratracheal inoculation of AHc vaccine induces protection against aerosolized botulinum neurotoxin A challenge in mice

Botulinum neurotoxin (BoNT), produced by Clostridium botulinum, is generally known to be the most poisonous of all biological toxins. In this study, we evaluate the protection conferred by intratracheal (i.t.) inoculation immunization with recombinant Hc subunit (AHc) vaccines against aerosolized BoNT/A intoxication. Three AHc vaccine formulations, i.e., conventional liquid, dry powder produced by spray freeze drying, and AHc dry powder reconstituted in water are prepared, and mice are immunized via i.t. inoculation or subcutaneous (s.c.) injection. Compared with s.c.-AHc-immunized mice, i.t.-AHc-immunized mice exhibit a slightly stronger protection against a challenge with 30,000× LD₅₀ aerosolized BoNT/A. Of note, only i.t.-AHc induces a significantly higher level of toxin-neutralizing mucosal secretory IgA (SIgA) production in the bronchoalveolar lavage of mice. In conclusion, our study demonstrates that the immune protection conferred by the three formulations of AHc is comparable, while i.t. immunization of AHc is superior to s.c. immunization against aerosolized BoNT/A intoxication.

Novel Lignin-Capped Silver Nanoparticles against Multidrug-Resistant Bacteria

The emergence of bacteria resistant to antibiotics and the resulting infections are increasingly becoming a public health issue. Multidrug-resistant (MDR) bacteria are responsible for infections leading to increased morbidity and mortality in hospitals, prolonged time of hospitalization, and additional burden to financial costs. Therefore, there is an urgent need for novel antibacterial agents that will both treat MDR infections and outsmart the bacterial evolutionary mechanisms, preventing further resistance development. In this study, a green synthesis employing nontoxic lignin as both reducing and capping agents was adopted to formulate stable and biocompatible silver-lignin nanoparticles (NPs) exhibiting antibacterial activity. The resulting silver-lignin NPs were approximately 20 nm in diameter and did not agglomerate after one year of storage at 4 °C. They were able to inhibit the growth of a panel of MDR clinical isolates, including Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii, at concentrations that did not affect the viability of a monocyte-derived THP-1 human cell line. Furthermore, the exposure of silver-lignin NPs to the THP-1 cells led to a significant increase in the secretion of the anti-inflammatory cytokine IL-10, demonstrating the potential of these particles to act as an antimicrobial and anti-inflammatory agent simultaneously. P. aeruginosa genes linked with efflux, heavy metal resistance, capsular biosynthesis, and quorum sensing were investigated for changes in gene expression upon sublethal exposure to the silver-lignin NPs. Genes encoding for membrane proteins with an efflux function were upregulated. However, all other genes were membrane proteins that did not efflux metals and were downregulated.

Insights from nanotechnology in COVID-19: prevention, detection, therapy and immunomodulation

The outbreak of SARS-CoV-2 infection has presented the world with an urgent demand for advanced diagnostics and therapeutics to prevent, treat and control the spread of infection. Nanotechnology seems to be highly relevant in this emergency due to the unique physicochemical properties of nanomaterials which offer versatile chemical functionalization to create advanced biomedical tools. Here, nano-intervention is discussed for designing effective strategies in developing advanced personal protective equipment kits, disinfectants, rapid and cost-effective diagnostics and therapeutics against the infection. We have also highlighted the nanoparticle-based vaccination approaches and how nanoparticles can regulate the host immune system against infection. Overall, this review discusses various nanoformulations that have shown clinical relevance or can be explored in the fight against COVID-19.

Biomaterial-based immunoengineering to fight COVID-19 and infectious diseases

Infection by SARS-CoV-2 virus often induces the dysregulation of immune responses, tissue damage, and blood clotting. Engineered biomaterials from the nano- to the macroscale can provide targeted drug delivery, controlled drug release, local immunomodulation, enhanced immunity, and other desirable functions to coordinate appropriate immune responses and to repair tissues. Based on the understanding of COVID-19 disease progression and immune responses to SARS-CoV-2, we discuss possible immunotherapeutic strategies and highlight biomaterial approaches from the perspectives of preventive immunization, therapeutic immunomodulation, and tissue healing and regeneration. Successful development of biomaterial platforms for immunization and immunomodulation will not only benefit COVID-19 patients, but also have broad applications for a variety of infectious diseases.

Differences in surface chemistry of iron oxide nanoparticles result in different routes of internalization

The efficient entry of nanotechnology-based pharmaceuticals into target cells is highly desired to reach high therapeutic efficiency while minimizing the side effects. Despite intensive research, the impact of the surface coating on the mechanism of nanoparticle uptake is not sufficiently understood yet. Herein, we present a mechanistic study of cellular internalization pathways of two magnetic iron oxide nanoparticles (MNPs) differing in surface chemistry into A549 cells. The MNP uptake was investigated in the presence of different inhibitors of endocytosis and monitored by spectroscopic and imaging techniques. The results revealed that the route of MNP entry into cells strongly depends on the surface chemistry of the MNPs. While serum bovine albumin-coated MNPs entered the cells via clathrin-mediated endocytosis (CME), caveolin-mediated endocytosis (CavME) or lipid rafts were preferentially involved in the internalization of polyethylene glycol-coated MNPs. Our data indicate that surface engineering can contribute to an enhanced delivery efficiency of nanoparticles.

Design and Comprehensive Characterization of Tetramethylpyrazine (TMP) for Targeted Lung Delivery as Inhalation Aerosols in Pulmonary Hypertension (PH): In Vitro Human Lung Cell Culture and In Vivo Efficacy

This is the first study reporting on the design and development innovative inhaled formulations of the novel natural product antioxidant therapeutic, tetramethylpyrazine (TMP), also known as ligustrazine. TMP is obtained from Chinese herbs belonging to the class of Ligusticum. It is known to have antioxidant properties. It can act as a Nrf2/ARE activator and a Rho/ROCK inhibitor. The present study reports for the first time on the comprehensive characterization of raw TMP (non-spray dried) and spray dried TMP in a systematic manner using thermal analysis, electron microscopy, optical microscopy, and Raman spectroscopy. The in vitro aerosol dispersion performance of spray dried TMP was tested using three different FDA-approved unit-dose capsule-based human dry powder inhaler devices. In vitro human cellular studies were conducted on pulmonary cells from different regions of the human lung to examine the biocompatibility and non-cytotoxicity of TMP. Furthermore, the efficacy of inhaled TMP as both liquid and dry powder inhalation aerosols was tested in vivo using the monocrotaline (MCT)-induced PH rat model.

Targeted Nanotherapeutics for Respiratory Diseases: Cancer, Fibrosis, and Coronavirus

Systemic delivery of therapeutics for treatment of lung diseases has several limitations including poor organ distribution of delivered payload with relatively low accumulation of active substances in the lungs and severe adverse side effects. In contrast, nanocarrier based therapeutics provide a broad range of opportunities due to their ability to encapsulate substances with different aqueous solubility, transport distinct types of cargo, target therapeutics specifically to the deceased organ, cell, or cellular organelle limiting adverse side effects and increasing the efficacy of therapy. Moreover, many nanotherapeutics can be delivered by inhalation locally to the lungs avoiding systemic circulation. In addition, nanoscale based delivery systems can be multifunctional, simultaneously carrying out several tasks including diagnostics, treatment and suppression of cellular resistance to the treatment. Nanoscale delivery systems improve the clinical efficacy of conventional therapeutics allowing new approaches for the treatment of respiratory diseases which are difficult to treat or possess intrinsic or acquired resistance to treatment. The present review summarizes recent advances in the development of nanocarrier based therapeutics for local and targeted delivery of drugs, nucleic acids and imaging agents for diagnostics and treatment of various diseases such as cancer, cystic fibrosis, and coronavirus.

Traditional Chinese medicine combined with pulmonary drug delivery system and idiopathic pulmonary fibrosis: Rationale and therapeutic potential

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Pathogenesis and characteristics of idiopathic pulmonary fibrosis (IPF) are presented.

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The history and current situation of traditional Chinese medicine (TCM) in treating lung diseases are introduced.

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Therapeutic mechanisms of different TCM to treat IPF are summarized.

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Advantages and types of pulmonary drug delivery systems (PDDS) are emphasized.

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Combining TCM with PDDS is a potential strategy to treat IPF.

Idiopathic pulmonary fibrosis (IPF) is a progressive pulmonary interstitial inflammatory disease of unknown etiology, and is also a sequela in severe patients with the Coronavirus Disease 2019 (COVID-19). Nintedanib and pirfenidone are the only two known drugs which are conditionally recommended for the treatment of IPF by the FDA. However, these drugs pose some adverse side effects such as nausea and diarrhoea during clinical applications. Therefore, it is of great value and significance to identify effective and safe therapeutic drugs to solve the clinical problems associated with intake of western medicine. As a unique medical treatment, Traditional Chinese Medicine (TCM) has gradually exerted its advantages in the treatment of IPF worldwide through a multi-level and multi-target approach. Further, to overcome the current clinical problems of oral and injectable intakes of TCM, pulmonary drug delivery system (PDDS) could be designed to reduce the systemic metabolism and adverse reactions of the drug and to improve the bioavailability of drugs. Through PubMed, Google Scholar, Web of Science, and CNKI, we retrieved articles published in related fields in recent years, and this paper has summarized twenty-seven Chinese compound prescriptions, ten single TCM, and ten active ingredients for effective prevention and treatment of IPF. We also introduce three kinds of inhaling PDDS, which supports further research of TCM combined with PDDS to treat IPF.

Unraveling the publication trends in inhalable nano-systems

Nano-systems (size range: 1 ~ 1000 nm) have been widely investigated as pulmonary drug delivery carriers, and the safety of inhaled nano-systems has aroused general interests. In this work, bibliometric analysis was performed to describe the current situation of related literature, figure out the revolutionary trends, and eventually forecast the possible future directions. The relevant articles and reviews from 2001 to 2020 were retrieved from the Web of Science Core Collection. The documents were processed by Clarivate Analytic associated with Web of Science database, Statistical Analysis Toolkit for Informetric, bibliometric online platform and VOSviewer, and the data were visualized. The bibliometric overview of the literature was described, citation analysis was performed, and research hotspots were showcased. The bibliometric analysis of 3362 documents of interest indicated that most of the relevant source titles were in the fields of toxicology, pharmacy, and materials science. The three research hotspots were the biological process of inhalable nano-systems in vivo, the manufacture of inhalable nano-systems, and the impact of nano-systems on human health in the environment. Toxicity and safety have always been the keywords. The USA was the major contributing country, and international collaboration and co-authorship were common phenomena. The general situation and development trend of literature of inhalable nano-systems were summarized. It was anticipated that bibliometrics analysis could provide new ideas for the future research of inhalable nano-systems.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11051-021-05384-1.

A review on chitosan and its development as pulmonary particulate anti-infective and anti-cancer drug carriers

Chitosan, as a biodegradable and biocompatible polymer, is characterized by anti-microbial and anti-cancer properties. It lately has received a widespread interest for use as the pulmonary particulate backbone materials of drug carrier for the treatment of infectious disease and cancer. The success of chitosan as pulmonary particulate drug carrier is a critical interplay of their mucoadhesive, permeation enhancement and site/cell-specific attributes. In the case of nanocarriers, various microencapsulation and micro-nano blending systems have been devised to equip them with an appropriate aerodynamic character to enable efficient pulmonary aerosolization and inhalation. The late COVID-19 infection is met with acute respiratory distress syndrome and cancer. Chitosan and its derivatives are found useful in combating HCoV and cancer as a function of their molecular weight, substituent type and its degree of substitution. The interest in chitosan is expected to rise in the next decade from the perspectives of drug delivery in combination with its therapeutic performance.

Novel Approaches for the Treatment of Pulmonary Tuberculosis

Tuberculosis (TB) is a contagious airborne disease caused by Mycobacterium tuberculosis, which primarily affects human lungs. The progression of drug-susceptible TB to drug-resistant strains, MDR-TB and XDR-TB, has become worldwide challenge in eliminating TB. The limitations of conventional TB treatment including frequent dosing and prolonged treatment, which results in patient’s noncompliance to the treatment because of treatment-related adverse effects. The non-invasive pulmonary drug administration provides the advantages of targeted-site delivery and avoids first-pass metabolism, which reduced the dose requirement and systemic adverse effects of the therapeutics. With the modification of the drugs with advanced carriers, the formulations may possess sustained released property, which helps in reducing the dosing frequency and enhanced patients’ compliances. The dry powder inhaler formulation is easy to handle and storage as it is relatively stable compared to liquids and suspension. This review mainly highlights the aerosolization properties of dry powder inhalable formulations with different anti-TB agents to understand and estimate the deposition manner of the drug in the lungs. Moreover, the safety profile of the novel dry powder inhaler formulations has been discussed. The results of the studies demonstrated that dry powder inhaler formulation has the potential in enhancing treatment efficacy.

Inhalable Nanoparticles/Microparticles of an AMPK and Nrf2 Activator for Targeted Pulmonary Drug Delivery as Dry Powder Inhalers

Metformin is an activator of the AMPK and Nrf2 pathways which are important in the pathology of several complex pulmonary diseases with unmet medical needs. Organic solution advanced spray drying in the absence of water in closed-mode was used to design and develop respirable dry powders. Following comprehensive characterization, the influence of physicochemical properties was correlated with performance as aerosols using inertial impaction and three different human dry powder inhaler (DPI) devices varying in device properties. In vitro cell assays were conducted to test safety in 2D human pulmonary cell lines and in 3D small airway epithelia comprising primary cells at the air-liquid interface (ALI). In addition, in vitro transepithelial electrical resistance (TEER) was carried out. Metformin remained crystalline following advanced spray drying under these conditions. All SD powders consisted of nanoparticles/microparticles in the solid state. In vitro aerosol dispersion performance showed high aerosolization for all SD metformin powders with all DPI devices tested. High emitted dose for all powders with all three DPI devices was measured. Differences in other aerosol performance parameters and the interplay between the properties of different formulations produced at specific pump rates and the three different DPI devices were correlated with spray drying pump rate and device properties. Safety over a wide metformin dose range was also demonstrated in vitro. Aerosol delivery of metformin nanoparticles/microparticles has the potential to be a new "first-in-class" therapeutic for the treatment of a number of pulmonary diseases including pulmonary vascular diseases such as pulmonary hypertension.

Design and development of innovative microparticulate/nanoparticulate inhalable dry powders of a novel synthetic trifluorinated chalcone derivative and Nrf2 agonist

Chalcone derivatives are shown to possess excellent anti-inflammatory and anti-oxidant properties which are of great interest in treating respiratory diseases such as acute lung injury (ALI), acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis (PF). This study successfully designed and developed dry powder inhaler (DPI) formulations of TMC (2-trifluoromethyl-2'-methoxychalone), a new synthetic trifluorinated chalcone and Nrf2 agonist, for targeted pulmonary inhalation aerosol drug delivery. An advanced co-spray drying particle engineering technique was used to design and produce microparticulate/nanoparticulate formulations of TMC with a suitable excipient (mannitol) as inhalable particles with tailored particle properties for inhalation. Raw TMC and co-spray dried TMC formulations were comprehensively characterized for the first time using scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) spectroscopy, thermal analysis, X-ray powder diffraction (XRPD), and molecular fingerprinting as dry powders by ATR-FTIR spectroscopy and Raman spectroscopy. Further, biocompatibility and suitability of formulations were tested with in vitro cellular transepithelial electrical resistance (TEER) in air-interface culture (AIC) using a human pulmonary airway cell line. The ability of these TMC formulations to perform as aerosolized dry powders was systematically evaluated by design of experiments (DOEs) using three different FDA-approved human inhaler devices followed by interaction parameter analyses. Multiple spray drying pump rates (25%, 75%, and 100%) successfully produced co-spray dried TMC:mannitol powders. Raw TMC exhibited a first-order phase transition temperature at 58.15 ± 0.38 °C. Furthermore, the results demonstrate that these innovative TMC dry powder particles are suitable for targeted delivery to the airways by inhalation.

An Overview on Spray-Drying of Protein-Loaded Polymeric Nanoparticles for Dry Powder Inhalation

The delivery of therapeutic proteins remains a challenge, despite recent technological advances. While the delivery of proteins to the lungs is the gold standard for topical and systemic therapy through the lungs, the issue still exists. While pulmonary delivery is highly attractive due to its non-invasive nature, large surface area, possibility of topical and systemic administration, and rapid absorption circumventing the first-pass effect, the absorption of therapeutic proteins is still ineffective, largely due to the immunological and physicochemical barriers of the lungs. Most studies using spray-drying for the nanoencapsulation of drugs focus on the delivery of conventional drugs, which are less susceptible to bioactivity loss, compared to proteins. Herein, the development of polymeric nanoparticles by spray-drying for the delivery of therapeutic proteins is reviewed with an emphasis on its advantages and challenges, and the techniques to evaluate their in vitro and in vivo performance. The protein stability within the carrier and the features of the carrier are properly addressed.

Inhaled cytotoxic chemotherapy: clinical challenges, recent developments, and future prospects

INTRODUCTION

Since 1968, inhaled chemotherapy has been evaluated and has shown promising results up to phase II but has not yet reached the market. This is due to technological and clinical challenges that require to be overcome with the aim of optimizing the efficacy and the tolerance of drug to re-open new developments in this field. Moreover, recent changes in the therapeutic standard of care for treating the patient with lung cancer also open new opportunities to combine inhaled chemotherapy with standard treatments.

AREAS COVERED

Clinical and technological concerns are highlighted from the reported clinical trials made with inhaled cytotoxic chemotherapies. This work then focuses on new pharmaceutical developments using dry powder inhalers as inhalation devices and on formulation strategies based on controlled drug release and with sustained lung retention or based on nanomedicine. Finally, new clinical strategies are described in regard to the impact of the immunotherapy on the patient's standard of care.

EXPERT OPINION

The choice of the drug, inhalation device, and formulation strategy as well as the position of inhaled chemotherapy in the patient's clinical care are crucial factors in optimizing local tolerance and efficacy as well as in its scalability and applicability in clinical practice.

Opportunities for biomaterials to address the challenges of COVID-19

The coronavirus disease 2019 (COVID-19) pandemic has revealed major shortcomings in our ability to mitigate transmission of infectious viral disease and provide treatment to patients, resulting in a public health crisis. Within months of the first reported case in China, the virus has spread worldwide at an unprecedented rate. COVID-19 illustrates that the biomaterials community was engaged in significant research efforts against bacteria and fungi with relatively little effort devoted to viruses. Accordingly, biomaterials scientists and engineers will have to participate in multidisciplinary antiviral research over the coming years. Although tissue engineering and regenerative medicine have historically dominated the field of biomaterials, current research holds promise for providing transformative solutions to viral outbreaks. To facilitate collaboration, it is imperative to establish a mutual language and adequate understanding between clinicians, industry partners, and research scientists. In this article, clinical perspectives are shared to clearly define emerging healthcare needs that can be met by biomaterials solutions. Strategies and opportunities for novel biomaterials intervention spanning diagnostics, treatment strategies, vaccines, and virus-deactivating surface coatings are discussed. Ultimately this review serves as a call for the biomaterials community to become a leading contributor to the prevention and management of the current and future viral outbreaks.

Biokinetics and clearance of inhaled gold ultrasmall-in-nano architectures

Among an organism's entry portals, the respiratory tract is one of the most promising routes for non-invasive administration of therapeutics for local and systemic delivery. On the other hand, it is the subtlest to protect from environmental pollution and microbial occurrences. Here, the biokinetics, distribution, and clearance trends of gold ultrasmall-in-nano architectures administered through a single intranasal application have been quantitatively evaluated. Apart from reaching the lung parenchyma, the (bio)degradable nano-architectures are able to translocate as well to secondary organs and be almost completely excreted within 10 days. These findings further support the clinical relevance of plasmonic nanomaterials for oncology and infectious disease treatment and management. Notably, this investigation also provides crucial information regarding the associated risks as a consequence of the pulmonary delivery of nanoparticles.

Antimicrobial Activity of Schinopsis brasiliensis Engler Extract-Loaded Chitosan Microparticles in Oral Infectious Disease

Enterococcus faecalis infections represent a health concern, mainly in oral diseases, in which treatments with chlorhexidine solution (0.2%) are often used; however, it presents high toxicity degree and several side effects. Based on this, the use of natural products as an alternative to treatment has been explored. Nonetheless, plant extracts have poor organoleptic characteristics that impair theirs in natura use. Therefore, this work aimed to evaluate the analytical profile, biological activity, and cytotoxicity in vitro of S. brasiliensis-loaded chitosan microparticles (CMSb) produced using different aspersion flow rates. The analytical fingerprint was obtained by FTIR and NIR spectra. Principal components analysis (PCA) was used to verify the similarity between the samples. The crystallinity degree was evaluated by X-ray diffraction (XRD). Phytochemical screening (PS) was performed to quantify phytocompounds. Antimicrobial activity was evaluated by minimum inhibitory concentration (MIC). Antibiofilm activity and bactericidal kinetics against E. faecalis (ATCC 29212 and MB 146-clinical isolated) were also assessed. The hemolytic potential was performed to evaluate the cytotoxicity. Data provided by FTIR, NIR, and PCA analyses revealed chemical similarity between all CMSb. Furthermore, the results from XRD analysis showed that the obtained CMSb present amorphous characteristic. Tannins and polyphenols were accurately quantified by the PS, but methodology limitations did not allow the flavonoid quantification. The low hemolytic potential assay indicates that all samples are safe. Antimicrobial assays revealed that CMSb were able to inhibit not only the E. faecalis ATCC growth but also the biofilm formation. Only one CMSb sample was able to inhibit the clinical strain. These results highlighted the CMSb antimicrobial potential and revealed this system as a promising product to treat infections caused by E. faecalis.

Current Status of Alginate in Drug Delivery

Alginate is one of the natural polymers that are often used in drug- and protein-delivery systems. The use of alginate can provide several advantages including ease of preparation, biocompatibility, biodegradability, and nontoxicity. It can be applied to various routes of drug administration including targeted or localized drug-delivery systems. The development of alginates as a selected polymer in various delivery systems can be adjusted depending on the challenges that must be overcome by drug or proteins or the system itself. The increased effectiveness and safety of sodium alginate in the drug- or protein-delivery system are evidenced by changing the physicochemical characteristics of the drug or proteins. In this review, various routes of alginate-based drug or protein delivery, the effectivity of alginate in the stem cells, and cell encapsulation have been discussed. The recent advances in the in vivo alginate-based drug-delivery systems as well as their toxicities have also been reviewed.

Prospects for RNAi Therapy of COVID-19

COVID-19 caused by the SARS-CoV-2 virus is a fast emerging disease with deadly consequences. The pulmonary system and lungs in particular are most prone to damage caused by the SARS-CoV-2 infection, which leaves a destructive footprint in the lung tissue, making it incapable of conducting its respiratory functions and resulting in severe acute respiratory disease and loss of life. There were no drug treatments or vaccines approved for SARS-CoV-2 at the onset of pandemic, necessitating an urgent need to develop effective therapeutics. To this end, the innate RNA interference (RNAi) mechanism can be employed to develop front line therapies against the virus. This approach allows specific binding and silencing of therapeutic targets by using short interfering RNA (siRNA) and short hairpin RNA (shRNA) molecules. In this review, we lay out the prospect of the RNAi technology for combatting the COVID-19. We first summarize current understanding of SARS-CoV-2 virology and the host response to viral entry and duplication, with the purpose of revealing effective RNAi targets. We then summarize the past experience with nucleic acid silencers for SARS-CoV, the predecessor for current SARS-CoV-2. Efforts targeting specific protein-coding regions within the viral genome and intragenomic targets are summarized. Emphasizing non-viral delivery approaches, molecular underpinnings of design of RNAi agents are summarized with comparative analysis of various systems used in the past. Promising viral targets as well as host factors are summarized, and the possibility of modulating the immune system are presented for more effective therapies. We place special emphasis on the limitations of past studies to propel the field faster by focusing on most relevant models to translate the promising agents to a clinical setting. Given the urgency to address lung failure in COVID-19, we summarize the feasibility of delivering promising therapies by the inhalational route, with the expectation that this route will provide the most effective intervention to halt viral spread. We conclude with the authors' perspectives on the future of RNAi therapeutics for combatting SARS-CoV-2. Since time is of the essence, a strong perspective for the path to most effective therapeutic approaches are clearly articulated by the authors.

Scope and limitations on aerosol drug delivery for the treatment of infectious respiratory diseases

The rise of antimicrobial resistance has created an urgent need for the development of new methods for antibiotics delivery to patients with pulmonary infections in order to mainly increase the effectiveness of the drugs administration, to minimize the risk of emergence of resistant strains, and to prevent patients reinfection. Since bacterial resistance is often related to antibiotic concentration, their pulmonary administration could eradicate strains resistant to the same drug at the concentration achieved through the systemic circulation. Pulmonary administration offers several advantages; it directly targets the site of the infection which allows the inhaled dose of the drug to be reduced compared to that administered orally or parenterally while keeping the same local effect. The review article is made with an objective to compile information about various existing modern technologies developed to provide greater patient compliance and reduce the undesirable side effect of the drugs. In conclusion, aerosol antibiotic delivery appears as one of the best technologies for the treatment of pulmonary infectious diseases and able to limit the systemic adverse effects related to the high drug dose and to make life easier for the patients.

Spray Drying for the Preparation of Nanoparticle-Based Drug Formulations as Dry Powders for Inhalation

Nanoparticle-based therapeutics have been used in pulmonary formulations to enhance delivery of poorly water-soluble drugs, protect drugs against degradation and achieve modified release and drug targeting. This review focuses on the use of spray drying as a solidification technique to produce microparticles containing nanoparticles (i.e., nanoparticle (NP) agglomerates) with suitable properties as dry powders for inhalation. The review covers the general aspects of pulmonary drug delivery with emphasis on nanoparticle-based dry powders for inhalation and the principles of spray drying as a method for the conversion of nanosuspensions to microparticles. The production and therapeutic applications of the following types of NP agglomerates are presented: nanoporous microparticles, nanocrystalline agglomerates, lipid-based and polymeric formulations. The use of alternative spray-drying techniques, namely nano spray drying, and supercritical CO2-assisted spray drying is also discussed as a way to produce inhalable NP agglomerates.

Nanoparticle-mediated macrophage targeting-a new inhalation therapy tackling tuberculosis

Despite the potent clinical efficacy of linezolid (LNZ) against drug-resistant tuberculosis, its safety and tolerability remain of major concern. Our objective is to develop antitubercular inhalable LNZ nano-embedded microparticles. In this context, LNZ incorporated in non-structured lipid carriers (NLCs) was characterized in terms of colloidal, morphological, thermal, and release profiles. The potential of LNZ-NLCs to cross mucosal barriers and invade alveolar macrophages (AM, MH-S cells) was appraised. In vivo proof of concept was accomplished via orotracheal administration to mice. Respirable microparticles prepared by spray drying NLCs with diluents were assessed for their size, shape, flowability, aerosolization performance, and lung deposition pattern. NLCs (809-827 nm in size, zeta potential - 37.4 to - 58.9 mV) ensued 19% LNZ loading and pH-independent sustained release. Penetration studies revealed 73% LNZ crossing mucus within 1 h. Meanwhile, viability assay on A549 cells ensured an IC50 of 1.2 and 0.32 mg/mL for plain and LNZ-NLCs, respectively. CLSM confirmed phagocytosis of NLCs by MH-S macrophages, while H&E staining demonstrated NLC accumulation in murine AM in vivo with no signs of histopathological/biochemical changes. Bronchoalveolar lavage showed significantly low levels of LDH and total proteins (TP) for LNZ-NLCs highlighting their superior safety. Respirable microparticles embedding LNZ-NLCs ensured excellent aerosolization (MMAD 2 μm, FPF 93%) denoting perfect alveolar deposition. The developed inhalation therapy provided sustained LNZ release, mucus penetrability, potential safety in therapeutic doses, in vitro and in vivo macrophage targetability, and preferential deposition in the deep lung. Overall positive outcomes rely on reduced dose, dosing frequency, and per se superior safety circumventing systemic-associated life-threatening side effects. Graphical abstract.

Emerging role of extracellular vesicles in the respiratory system

Extracellular vesicles (EVs) present numerous biomedical ways of studying disease and pathology. They function as protective packaging for the delivery of controlled concentrations of miRNAs and effector molecules, including cytokines, chemokines, genetic material, and small signaling molecules. Previous studies of EVs have yielded valuable insights into pathways of intercellular communication that affect a variety of biological processes and disease responses. The roles of EVs, specifically microRNA-containing EVs (EV-miRNAs), in either mitigating or exacerbating pulmonary disease symptoms are numerous and show promise in helping us understand pulmonary disease pathology. Because of their well-documented involvement in pulmonary diseases, EVs show promise both as possible diagnostic biomarkers and as therapeutic agents. This review surveys the physiological functions of EVs in the respiratory system and outlines the pulmonary disease states in which EVs are involved in intercellular crosstalk. This review also discusses the potential clinical applications of EV-miRNAs in pulmonary diseases.

Studies of tiny membrane-bound sacs called extracellular vesicles (EVs), which bud from cells naturally but are also implicated in disease, offer insights into respiratory health and disease, and could be used to deliver therapies into respiratory system cells. Joshua Holtzman at Oberlin College, Ohio, USA, and Heedoo Lee at Changwon National University in South Korea review current understanding of the role of EVs in the respiratory system and their potential uses in treatment. Researchers are discovering how EVs deliver signaling molecules to promote respiratory health, and how they can be involved in cancer, autoimmunity, asthma and other diseases. Early trials using EVs to deliver conventional drugs, and small RNA molecules that can control gene activity suggest great potential for treating a range of serious respiratory conditions. Analysis of EVs may also assist in diagnosis.

Effect of Poly(vinyl alcohol) on Nanoencapsulation of Budesonide in Chitosan Nanoparticles via Ionic Gelation and Its Improved Bioavailability

Chitosan (CS) is a polymer extensively used in drug delivery formulations mainly due to its biocompatibility and low toxicity. In the present study, chitosan was used for nanoencapsulation of a budesonide (BUD) drug via the well-established ionic gelation technique and a slight modification of it, using also poly(vinyl alcohol) (PVA) as a surfactant. Scanning electron microscopy (SEM) micrographs revealed that spherical nanoparticles were successfully prepared with average sizes range between 363 and 543 nm, as were measured by dynamic light scattering (DLS), while zeta potential verified their positive charged surface. X-ray diffraction (XRD) patterns revealed that BUD was encapsulated in crystalline state in nanoparticles but with a lower degree of crystallinity than the neat drug, which was also proven by differential scanning calorimetry (DSC) and melting peak measurements. This could be attributed to interactions that take place between BUD and CS, which were revealed by FTIR and by an extended computational study. An in vitro release study of budesonide showed a slight enhancement in the BUD dissolution profile, compared to the neat drug. However, drug release was substantially increased by introducing PVA during the nanoencapsulation procedure, which is attributed to the higher amorphization of BUD on these nanoparticles. The release curves were analyzed using a diffusion model that allows estimation of BUD diffusivity in the nanoparticles.

Advanced In Vitro Testing Strategies and Models of the Intestine for Nanosafety Research

There is growing concern about the potential adverse effects of oral exposure to engineered nanomaterials (ENM). Recent years have witnessed major developments in and advancement of intestinal in vitro models for nanosafety evaluation. The present paper reviews the key factors that should be considered for inclusion in nonanimal alternative testing approaches to reliably reflect the in vivo dynamics of the physicochemical properties of ENM as well the intestinal physiology and morphology. Currently available models range from simple cell line-based monocultures to advanced 3D systems and organoids. In addition, in vitro approaches exist to replicate the mucous barrier, digestive processes, luminal flow, peristalsis, and interactions of ENM with the intestinal microbiota. However, while the inclusion of a multitude of individual factors/components of particle (pre)treatment, exposure approach, and cell model approximates in vivo-like conditions, such increasing complexity inevitably affects the system's robustness and reproducibility. The selection of the individual modules to build the in vitro testing strategy should be driven and justified by the specific purpose of the study and, not least, the intended or actual application of the investigated ENM. Studies that address health hazards of ingested ENM likely require different approaches than research efforts to unravel the fundamental interactions or toxicity mechanisms of ENM in the intestine. Advanced reliable and robust in vitro models of the intestine, especially when combined in an integrated testing approach, offer great potential to further improve the field of nanosafety research.

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.

Multimodal Precision Imaging of Pulmonary Nanoparticle Delivery in Mice: Dynamics of Application, Spatial Distribution, and Dosimetry

Targeted delivery of nanomedicine/nanoparticles (NM/NPs) to the site of disease (e.g., the tumor or lung injury) is of vital importance for improved therapeutic efficacy. Multimodal imaging platforms provide powerful tools for monitoring delivery and tissue distribution of drugs and NM/NPs. This study introduces a preclinical imaging platform combining X-ray (two modes) and fluorescence imaging (three modes) techniques for time-resolved in vivo and spatially resolved ex vivo visualization of mouse lungs during pulmonary NP delivery. Liquid mixtures of iodine (contrast agent for X-ray) and/or (nano)particles (X-ray absorbing and/or fluorescent) are delivered to different regions of the lung via intratracheal instillation, nasal aspiration, and ventilator-assisted aerosol inhalation. It is demonstrated that in vivo propagation-based phase-contrast X-ray imaging elucidates the dynamic process of pulmonary NP delivery, while ex vivo fluorescence imaging (e.g., tissue-cleared light sheet fluorescence microscopy) reveals the quantitative 3D drug/particle distribution throughout the entire lung with cellular resolution. The novel and complementary information from this imaging platform unveils the dynamics and mechanisms of pulmonary NM/NP delivery and deposition for each of the delivery routes, which provides guidance on optimizing pulmonary delivery techniques and novel-designed NM for targeting and efficacy.

Rifampicin-Carbohydrate Spray-Dried Nanocomposite: A Futuristic Multiparticulate Platform For Pulmonary Delivery

Purpose

Rifampicin, a first-line anti-tuberculosis drug, was loaded into a carbohydrate-based spray-dried nanocomposite with the aim to design a dry powder inhalation formulation. This strategy can enable efficient distribution of rifampicin within the lungs, localizing its action, enhancing its bioavailability and reducing its systemic exposure consequently side effects.

Methods

The respirable nanocomposite was developed utilizing spray drying of rifampicin nanosuspension employing a combination of mannitol, maltodextrin and leucine as microparticles matrix formers. Detailed physicochemical characterization and in-vitro inhalation properties of the nanocomposite particles were investigated. Compatibility studies were carried out using differential scanning calorimetry and Infrared spectroscopy techniques. Moreover, pulmonary in-vitro cytotoxicity on alveolar basal epithelial cells was performed and evaluated.

Results

Nanocomposite-based rifampicin-loaded dry inhalable powder containing maltodextrin, mannitol and leucine at a ratio of 2:1:1 was successfully formulated. Rifampicin loading efficiency into the carbohydrate nanocomposite was in the range of 89.3% to 99.2% w/w with a suitable particle size (3.47-6.80 µm) and unimodal size distribution. Inhalation efficiency of the spray-dried nanosuspension was significantly improved after transforming into an inhalable carbohydrate composite. Specifically, mannitol-based powder had higher respirable fraction (49.91%) relative to the corresponding formulation of maltodextrin. Additionally, IC₅₀ value of rifampicin nanocomposite was statistically significantly higher than that of free drug thus providing superior safety profile on lung tissues.

Conclusion

The obtained results suggested that spray drying of rifampicin nanosuspension utilizing carbohydrates as matrix formers can enhance drug inhalation performance and reduce cellular toxicity. Thus, representing an effective safer pulmonary delivery of anti-tuberculosis drugs.

Fumaryl diketopiperazine based effervescent microparticles to escape macrophage phagocytosis for enhanced treatment of pneumonia via pulmonary delivery

The treatment of pulmonary infections with antibiotics administered via pulmonary delivery provides for higher local therapeutic efficacy rather than through systemic administration. Pneumonia is globally considered a major cause of death due to a lack of proper medication. The treatment of pneumonia with inhalable antibiotics (such as azithromycin (AZM)) can provide a maximum pulmonary therapeutic effect without significant systemic side effects. Compared to non-effervescent microparticles, effervescent microparticles can provide an active driving force to release loaded antibiotics for subsequent distribution deep into the lung by virtue of its smaller size. In this study, N-fumaroylated diketopiperazine (FDKP) was used as a carrier to prepare effervescent inhalable microparticles loaded with AZM (AZM@FDKP-E-MPs). This effervescent dry powder was characterized for both in vitro and in vivo deposition in the lung and the results obtained showed significant improvement in lung deposition and anti-bacterial efficiency, suggesting a strong potential application for pneumonia treatment.

Preparation, Optimization, and In Vivo Evaluation of Nanoparticle-Based Formulation for Pulmonary Delivery of Anticancer Drug

Background and Oobjectives: Lung cancer, a pressing issue in present-day society due to its high prevalence and mortality rate, can be managed effectively by long-term delivery of anticancer agents encapsulated in nanoparticles in the form of inhalable dry powder. This approach is expected to be of strategic importance in the management of lung cancer and is a developing area in current research. In the present investigation, we report on the formulation and characterization of docetaxel inhalable nanoparticles as a viable alternative for effective treatment of non-small cell lung cancer as a long-term delivery choice. Materials and Methods: Poloxamer (PLX-188) coated poly(lactic-co-glycolic acid) (PLGA) nanoparticles containing docetaxel (DTX-NPs) were prepared by simple oil in water (o/w) single emulsification-solvent evaporation process. The nanoparticles were collected as pellet by centrifugation, dispersed in mannitol solution, and lyophilized to get dry powder. Results: Optimized DTX-NPs were smooth and spherical in morphology, had particle size around 200 nm, zeta potential around −36 mV, and entrapment efficiency of around 60%. The in vitro anticancer assay was assessed and it was observed that nanoparticle-based formulation exhibited enhanced cytotoxicity when compared to the free form of the drug post 48 h. On examining for in vitro drug release, slow but continuous release was seen until 96 h following Higuchi release kinetics. DTX-NPs were able to maintain their desired characteristics when studied at accelerated conditions of stability. Conclusions: In-vivo study indicated that the optimized nanoparticles were well retained in lungs and that the drug level could be maintained for a longer duration if given in the form of DTX-NPs by the pulmonary route. Thus, the non-invasive nature and target specificity of DTX-NPs paves the way for its future use as a pulmonary delivery for treating non-small cell lung cancer (NSCLC).

Selective drug deposition in lungs through pulmonary drug delivery system for effective management of drug-resistant TB

INTRODUCTION

The emergence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) is a major health issue and continues to be a global health concern. Despite significant advancements in treatment modalities, ~1.6 million deaths worldwide occur due to TB infection. This is because of tuberculosis reservoirs in the alveoli making it a challenge for the formulation scientist to target this.

AREAS COVERED

This review recent investigations on the forefront of pulmonary drug delivery for managing MDR-TB and XDR-TB. Novel delivery systems like liposomes, niosomes, employing carbohydrate, and -coated molecules via conjugation to selectively deliver the drugs to the lung TB reservoir via pulmonary administration are discussed.

EXPERT OPINION

Poor patient adherence to treatment due to side effects and extended therapeutic regimen leads to drug-resistant TB. Thus, it is essential to design novel strategies this issue by developing new chemical entities and/or new delivery systems for delivery to the lungs, consequently reducing the side effects, the frequency and the duration of treatment. Delivery of drugs to enhance the efficacy of new/existing anti-TB drugs to overcome the resistance and enhance patient compliance is underway.

Utilizing the Lung as a Model to Study Nanoparticle-Based Drug Delivery Systems

Intranasal administration is a highly effective route for drug delivery and biodistribution studies. Indeed, this route of delivery has become the method of choice to distribute diverse pharmacological agents both locally and systemically. In the majority of preclinical animal models and in human patients, intranasal administration is the preferred method to deliver therapeutic agents to the airways and lungs. However, issues with drug stability and controlled release in the respiratory tract are common problems with many therapeutic agents. Nanoparticle delivery via intranasal administration has tremendous potential to circumvent these common issues. Over the past 30 years nanoparticles have gained increased interest as therapeutic delivery vehicles and as tools for improved bioimaging. Integral to the success of nanoparticles in drug delivery and biodistribution is the utilization of mouse models to characterize therapeutic strategies under physiologically relevant in situ conditions. Here, we describe a model of nanoparticle administration to the lungs utilizing intranasal administration and discuss a variety of highly useful techniques to evaluate nanoparticle up-take, biodistribution, and immune response. While these protocols have been optimized for intranasal administration of common fluorescently labeled nanoparticles, they can be applied to any nanoparticle or drug delivery system of interest targeting the lungs and airways.

Development of inhalable curcumin loaded Nano-in-Microparticles for bronchoscopic photodynamic therapy

Photodynamic therapy is amongst the most rapidly developing therapeutic strategies against cancer. However, most photosensitizers are administered intravenously with very few reports about pulmonary applications. To address this issue, an inhalable formulation consisting of nanoparticles loaded with photosensitizer (i.e. curcumin) was developed. The nanoparticles were prepared using nanoprecipitation method. Dynamic light scattering measurements of the curcumin loaded nanoparticles revealed a hydrodynamic diameter of 181.20 ± 11.52 nm. In vitro irradiation experiments with human lung epithelial carcinoma cells (A549) showed a selective cellular toxicity of the nanoparticles upon activation using LED irradiating device. Moreover, curcumin nanoparticles exhibited a dose-dependent photocytotoxicity and the IC₅₀ values of curcumin were directly dependent on the radiation fluence used. The nanoparticles were subsequently spray dried using mannitol as a stabilizer to produce Nano-in-Microparticles with appropriate aerodynamic properties for a sufficient deposition in the lungs. This was confirmed using the next generation impactor, which revealed a large fine particle fraction (64.94 ± 3.47%) and a mass median aerodynamic diameter of 3.02 ± 0.07 μm. Nano-in-Microparticles exhibited a good redispersibility and disintegrated into the original nanoparticles upon redispersion in aqueous medium. The Langmuir monolayer experiments revealed an excellent compatibility of the nanoparticles with the lung surfactant. Results from this study showed that the Nano-in-Microparticles are promising drug carriers for the photodynamic therapy of lung cancer.

Strategies for improving diabetic therapy via alternative administration routes that involve stimuli-responsive insulin-delivering systems

The encapsulation of insulin in micro- or nanodelivery systems may eliminate the need for frequent subcutaneous injections, improving the quality of life of diabetic patients. Formulations for oral, intranasal, pulmonary, subcutaneous, and transdermal administration have been developed. The use of stimuli-responsive polymeric carriers that can release the encapsulated drug in response to changes of the environmental stimuli or external activation enables the design of less invasive or non-invasive systems for smart insulin delivery from depots in the body. This article will look at strategies for the development of responsive delivery systems and the future meeting of the demands of new modes of insulin delivery.