Anticancer drug delivery: Investigating the impacts of viscosity on lipid-based formulations for pulmonary targeting

Pulmonary drug delivery via aerosolization is a non-intrusive method for achieving localized and systemic effects. The aim of this study was to establish the impact of viscosity as a novel aspect (i.e., low, medium and high) using various lipid-based formulations (including liposomes (F1-F3), transfersomes (F4-F6), micelles (F7-F9) and nanostructured lipid carriers (NLCs; F10-F12)) as well as to investigate their impact on in-vitro nebulization performance using Trans-resveratrol (TRES) as a model anticancer drug. Based on the physicochemical properties, micelles (F7-F9) elicited the smallest particle size (12-174 nm); additionally, all formulations tested exhibited high entrapment efficiency (>89 %). Through measurement using capillary viscometers, NLC formulations exhibited the highest viscosity (3.35-10.04 m2/sec). Upon using a rotational rheometer, formulations exhibited shear-thinning (non-Newtonian) behaviour. Air jet and vibrating mesh nebulizers were subsequently employed to assess nebulization performance using an in-vitro model. Higher viscosity formulations elicited a prolonged nebulization time. The vibrating mesh nebulizer exhibited significantly higher emitted dose (ED), fine particle fraction (FPF) and fine particle dose (FPD) (up to 97 %, 90 % and 64 µg). Moreover, the in-vitro release of TRES was higher at pH 5, demonstrating an alignment of the release profile with the Korsmeyer-Peppas model. Thus, formulations with higher viscosity paired with a vibrating mesh nebulizer were an ideal combination for delivering and targeting peripheral lungs.

Ciprofloxacin-Loaded Inhalable Formulations against Lower Respiratory Tract Infections: Challenges, Recent Advances, and Future Perspectives

Inhaled ciprofloxacin (CFX) has been investigated as a treatment for lower respiratory tract infections (LRTIs) associated with cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), and bronchiectasis. The challenges in CFX effectiveness for LRTI treatment include poor aqueous solubility and therapy resistance. CFX dry powder for inhalation (DPI) formulations were well-tolerated, showing a remarkable decline in overall bacterial burden compared to a placebo in bronchiectasis patients. Recent research using an inhalable powder combining Pseudomonas phage PEV20 with CFX exhibited a substantial reduction in bacterial density in mouse lungs infected with clinical P. aeruginosa strains and reduced inflammation. Currently, studies suggest that elevated biosynthesis of fatty acids could serve as a potential biomarker for detecting CFX resistance in LRTIs. Furthermore, inhaled CFX has successfully addressed various challenges associated with traditional CFX, including the incapacity to eliminate the pathogen, the recurrence of colonization, and the development of resistance. However, further exploration is needed to address three key unresolved issues: identifying the right patient group, determining the optimal treatment duration, and accurately assessing the risk of antibiotic resistance, with additional multicenter randomized controlled trials suggested to tackle these challenges. Importantly, future investigations will focus on the effectiveness of CFX DPI in bronchiectasis and COPD, aiming to differentiate prognoses between these two conditions. This review underscores the importance of CFX inhalable formulations against LRTIs in preclinical and clinical sectors, their challenges, recent advancements, and future perspectives.

Impact of Nebulization on the Physicochemical Properties of Polymer-Lipid Hybrid Nanoparticles for Pulmonary Drug Delivery

Nanoparticles (NPs) have shown significant potential for pulmonary administration of therapeutics for the treatment of chronic lung diseases in a localized and sustained manner. Nebulization is a suitable method of NP delivery, particularly in patients whose ability to breathe is impaired due to lung diseases. However, there are limited studies evaluating the physicochemical properties of NPs after they are passed through a nebulizer. High shear stress generated during nebulization could potentially affect the surface properties of NPs, resulting in the loss of encapsulated drugs and alteration in the release kinetics. Herein, we thoroughly examined the physicochemical properties as well as the therapeutic effectiveness of Infasurf lung surfactant (IFS)-coated PLGA NPs previously developed by us after passing through a commercial Aeroneb® vibrating-mesh nebulizer. Nebulization did not alter the size, surface charge, IFS coating and bi-phasic release pattern exhibited by the NPs. However, there was a temporary reduction in the initial release of encapsulated therapeutics in the nebulized compared to non-nebulized NPs. This underscores the importance of evaluating the drug release kinetics of NPs using the inhalation method of choice to ensure suitability for the intended medical application. The cellular uptake studies demonstrated that both nebulized and non-nebulized NPs were less readily taken up by alveolar macrophages compared to lung cancer cells, confirming the IFS coating retention. Overall, nebulization did not significantly compromise the physicochemical properties as well as therapeutic efficacy of the prepared nanotherapeutics.

Research Progress on Liposome Pulmonary Delivery of Mycobacterium tuberculosis Nucleic Acid Vaccine and Its Mechanism of Action

Traditional vaccines have played an important role in the prevention and treatment of infectious diseases, but they still have problems such as low immunogenicity, poor stability, and difficulty in inducing lasting immune responses. In recent years, the nucleic acid vaccine has emerged as a relatively cheap and safe new vaccine. Compared with traditional vaccines, nucleic acid vaccine has some unique advantages, such as easy production and storage, scalability, and consistency between batches. However, the direct administration of naked nucleic acid vaccine is not ideal, and safer and more effective vaccine delivery systems are needed. With the rapid development of nanocarrier technology, the combination of gene therapy and nanodelivery systems has broadened the therapeutic application of molecular biology and the medical application of biological nanomaterials. Nanoparticles can be used as potential drug-delivery vehicles for the treatment of hereditary and infectious diseases. In addition, due to the advantages of lung immunity, such as rapid onset of action, good efficacy, and reduced adverse reactions, pulmonary delivery of nucleic acid vaccine has become a hot spot in the field of research. In recent years, lipid nanocarriers have become safe, efficient, and ideal materials for vaccine delivery due to their unique physical and chemical properties, which can effectively reduce the toxic side effects of drugs and achieve the effect of slow release and controlled release, and there have been a large number of studies using lipid nanocarriers to efficiently deliver target components into the body. Based on the delivery of tuberculosis (TB) nucleic acid vaccine by lipid carrier, this article systematically reviews the advantages and mechanism of liposomes as a nucleic acid vaccine delivery carrier, so as to lay a solid foundation for the faster and more effective development of new anti-TB vaccine delivery systems in the future.

Liposomes for Inhalation

Inhalation of liposomes formulated with phospholipids similar to endogenous lung surfactants and lipids offers biocompatibility and versatility within the pulmonary medicine field to treat a range of diseases such as lung cancer, cystic fibrosis and lung infections. Manipulation of the physicochemical properties of liposomes enables innovative design of the carrier to meet specific delivery, release and targeting requirements. This delivery system offers several benefits: improved pharmacokinetics with reduced toxicity, enhanced therapeutic efficacy, increased delivery of poorly soluble drugs, taste masking, biopharmaceutics degradation protection and targeted cellular therapy. This section provides an overview of liposomal formulation and delivery, together with their applications for different disease states in the lung.

Nebulization and In Vitro Upper Airway Deposition of Liposomal Carrier Systems

Liposomal carrier systems have emerged as a promising technology for pulmonary drug delivery. This study focuses on two selected liposomal systems, namely, dipalmitoylphosphatidylcholine stabilized by phosphatidic acid and cholesterol (DPPC-PA-Chol) and dipalmitoylphosphatidylcholine stabilized by polyethylene glycol and cholesterol (DPPC-PEG-Chol). First, the research investigates the stability of these liposomal systems during the atomization process using different kinds of nebulizers (air-jet, vibrating mesh, and ultrasonic). The study further explores the aerodynamic particle size distribution of the aerosol generated by the nebulizers. The nebulizer that demonstrated optimal stability and particle size was selected for more detailed investigation, including Andersen cascade impactor measurements, an assessment of the influence of flow rate and breathing profiles on aerosol particle size, and an in vitro deposition study on a realistic replica of the upper airways. The most suitable combination of a nebulizer and liposomal system was DPPC-PA-Chol nebulized by a Pari LC Sprint Star in terms of stability and particle size. The influence of the inspiration flow rate on the particle size was not very strong but was not negligible either (decrease of Dv50 by 1.34 μm with the flow rate increase from 8 to 60 L/min). A similar effect was observed for realistic transient inhalation. According to the in vitro deposition measurement, approximately 90% and 70% of the aerosol penetrated downstream of the trachea using the stationary flow rate and the realistic breathing profile, respectively. These data provide an image of the potential applicability of liposomal carrier systems for nebulizer therapy. Regional lung drug deposition is patient-specific; therefore, deposition results might vary for different airway geometries. However, deposition measurement with realistic boundary conditions (airway geometry, breathing profile) brings a more realistic image of the drug delivery by the selected technology. Our results show how much data from cascade impactor testing or estimates from the fine fraction concept differ from those of a more realistic case.

Aerosol delivery and spatiotemporal tissue distribution of hydroxychloroquine in rat lung

Inhalation enables the delivery of drugs directly to the lung, increasing the retention for prolonged exposure and maximizing the therapeutic index. However, the differential regional lung exposure kinetics and systemic pharmacokinetics are not fully known, and their estimation is critical for pulmonary drug delivery. The study evaluates the pharmacokinetics of hydroxychloroquine in different regions of the respiratory tract for multiple routes of administration. We also evaluated the influence of different inhaled formulations on systemic and lung pharmacokinetics by identifying suitable nebulizers followed by early characterization of emitted aerosol physicochemical properties. The salt- and freebase-based formulations required different nebulizers and generated aerosol with different physicochemical properties. An administration of hydroxychloroquine by different routes resulted in varied systemic and lung pharmacokinetics, with oral administration resulting in low tissue concentrations in all regions of the respiratory tract. A nose-only inhalation exposure resulted in higher and sustained lung concentrations of hydroxychloroquine with a lung parenchyma-to-blood ratio of 386 after 1440 min post-exposure. The concentrations of hydroxychloroquine in different regions of the respiratory tract (i.e., nasal epithelium, larynx, trachea, bronchi, and lung parenchyma) varied over time, indicating different retention kinetics. The spatiotemporal distribution of hydroxychloroquine in the lung is different due to the heterogeneity of cell types, varying blood perfusion rate, clearance mechanisms, and deposition of inhaled aerosol along the respiratory tract. In addition to highlighting the varied lung physiology, these results demonstrate the ability of the lung to retain increased levels of inhaled lysosomotropic drugs. Such findings are critical for the development of future inhalation-based therapeutics, aiming to optimize target site exposure, enable precision medicine, and ultimately enhance clinical outcomes.

Lipidated brush-PEG polymers as low molecular weight pulmonary drug delivery platforms

OBJECTIVES

Nanomedicines are being actively developed as inhalable drug delivery systems. However, there is a distinct utility in developing smaller polymeric systems that can bind albumin in the lungs. We therefore examined the pulmonary pharmacokinetic behavior of a series of lipidated brush-PEG (5 kDa) polymers conjugated to 1C2, 1C12 lipid or 2C12 lipids.

METHODS

The pulmonary pharmacokinetics, patterns of lung clearance and safety of polymers were examined in rats. Permeability through monolayers of primary human alveolar epithelia, small airway epithelia and lung microvascular endothelium were also investigated, along with lung mucus penetration and cell uptake.

RESULTS

Polymers showed similar pulmonary pharmacokinetic behavior and patterns of lung clearance, irrespective of lipid molecular weight and albumin binding capacity, with up to 30% of the dose absorbed from the lungs over 24 h. 1C12-PEG showed the greatest safety in the lungs. Based on its larger size, 2C12-PEG also showed the lowest mucus and cell membrane permeability of the three polymers. While albumin had no significant effect on membrane transport, the cell uptake of C12-conjugated PEGs were increased in alveolar epithelial cells.

CONCLUSION

Lipidated brush-PEG polymers composed of 1C12 lipid may provide a useful and novel alternative to large nanomaterials as inhalable drug delivery systems.

Docetaxel liposomes for lung targeted delivery: development and evaluation

Docetaxel (DTX) is an artificial semi-synthetic second-generation taxane anti-tumor drug, which is suitable for the treatment of various cancers such as lung cancer. The route of administration of DTX formulations has been extended to oral, intravenous, and rectal, with few studies on pulmonary administration being reported. Here, we had developed DTX liposomes (DTX-lips) for pulmonary inhalation administration. The particle size of the preparation was 125 nm, the encapsulation efficiency was 94.4 ± 0.14%, and the drug loading capacity was 1.26 ± 0.01%. It had good stability. The fine particle fraction with aerodynamic diameter less than 6.4 μm accounts for 64.63 ± 0.12%, showed excellent aerosolization performance. DTX-lips were slow to release in simulated lung fluid. The fluorescence distribution experimented in mice and tissues showed that the fluorescence of the inhaled liposome group was mainly distributed in the lung, and the retention time was significantly prolonged as compared with those of the other two groups. No significant fluorescence was observed in other tissues, which was conducive to the full effect of the drug in the lung tissue. DTX-lips had no damage to respiratory system and whole body. These results indicated that the inhaled DTX-lips had good lung targeting, reduced accumulation in other organs, and improved the safety and effectiveness of the drug.

Natural products and their analogues acting against Mycobacterium tuberculosis: A recent update

Tuberculosis (TB) remains one of the deadliest infectious diseases caused by Mycobacterium tuberculosis (M.tb). It is responsible for significant causes of mortality and morbidity worldwide. M.tb possesses robust defense mechanisms against most antibiotic drugs and host responses due to their complex cell membranes with unique lipid molecules. Thus, the efficacy of existing front-line drugs is diminishing, and new and recurring cases of TB arising from multidrug-resistant M.tb are increasing. TB begs the scientific community to explore novel therapeutic avenues. A precise knowledge of the compounds with their mode of action could aid in developing new anti-TB agents that can kill latent and actively multiplying M.tb. This can help in the shortening of the anti-TB regimen and can improve the outcome of treatment strategies. Natural products have contributed several antibiotics for TB treatment. The sources of anti-TB drugs/inhibitors discussed in this work are target-based identification/cell-based and phenotypic screening from natural products. Some of the recently identified natural products derived leads have reached clinical stages of TB drug development, which include rifapentine, CPZEN-45, spectinamide-1599 and 1810. We believe these anti-TB agents could emerge as superior therapeutic compounds to treat TB over known Food and Drug Administration drugs.

Lipid-Based Inhalable Micro- and Nanocarriers of Active Agents for Treating Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) afflicts about 2 million people worldwide, with both genetic (familial) and environmental factors contributing to its development and spread. The inadequacy of currently available therapeutic techniques, such as surgery, chemotherapy, and radiation therapy, in addressing NSCLC is reflected in the very low survival rate of this disease. Therefore, newer approaches and combination therapy regimens are required to reverse this dismal scenario. Direct administration of inhalable nanotherapeutic agents to the cancer sites can potentially lead to optimal drug use, negligible side effects, and high therapeutic gain. Lipid-based nanoparticles are ideal agents for inhalable delivery owing to their high drug loading, ideal physical traits, sustained drug release, and biocompatibility. Drugs loaded within several lipid-based nanoformulations, such as liposomes, solid-lipid nanoparticles, lipid-based micelles, etc., have been developed as both aqueous dispersed formulations as well as dry-powder formulations for inhalable delivery in NSCLC models in vitro and in vivo. This review chronicles such developments and charts the future prospects of such nanoformulations in the treatment of NSCLC.

Liposomal form of erlotinib for local inhalation administration and efficiency of its transport to the lungs

This contribution is focused on the preparation of a liposomal drug delivery system of erlotinib resisting the nebulization process that could be used for local treatment of non-small-cell lung cancer. Liposomes with different compositions were formulated to reveal their influence on the encapsulation efficiency of erlotinib. An encapsulation efficiency higher than 98 % was achieved for all vesicles containing phosphatidic acid (d ≈ 100 nm, ζ = - 43 mV) even in the presence of polyethylene glycol (d ≈ 150 nm, ζ = - 17 mV) which decreased this value in all other formulas. The three most promising formulations were nebulized by two air-jet and two vibrating mesh nebulizers, and the aerosol deposition in lungs was calculated by tools of computational fluid and particle mechanics. According to the numerical simulations and measurements of liposomal stability, air-jet nebulizers generated larger portion of the aerosol able to penetrate deeper into the lungs, but the delivery is likely to be more efficient when the formulation is administered by Aerogen Solo vibrating mesh nebulizer because of a higher portion of intact vesicles after the nebulization. The leakage of encapsulated drug from liposomes nebulized by this nebulizer was lower than 2 % for all chosen vesicles.

Targeted GATA3 knockdown in activated T cells via pulmonary siRNA delivery as novel therapy for allergic asthma

GATA3 gene silencing in activated T cells displays a promising option to early-on undermine pathological pathways in the disease formation of allergic asthma. The central transcription factor of T helper 2 (Th2) cell cytokines IL-4, IL-5, and IL-13 plays a major role in immune and inflammatory cascades underlying asthmatic processes in the airways. Pulmonary delivery of small interfering RNAs (siRNA) to induce GATA3 knockdown within disease related T cells of asthmatic lungs via RNA interference (RNAi) presents an auspicious base to realize this strategy, however, still faces some major hurdles. Main obstacles for successful siRNA delivery in general comprise stability and targeting issues, while in addition the transfection of T cells presents a particularly challenging task itself. In previous studies, we have developed and advanced an eligible siRNA delivery system composed of polyethylenimine (PEI) as polycationic carrier, transferrin (Tf) as targeting ligand and melittin (Mel) as endosomolytic agent. Resulting Tf-Mel-PEI polyplexes exhibited ideal characteristics for targeted siRNA delivery to activated T cells and achieved efficient and sequence-specific gene knockdown in vitro. In this work, the therapeutic potential of this carrier system was evaluated in an optimized cellular model displaying the activated status of asthmatic T cells. Moreover, a suitable siRNA sequence combination was found for effective gene silencing of GATA3. To confirm the translatability of our findings, Tf-Mel-PEI polyplexes were additionally tested ex vivo in activated human precision-cut lung slices (PCLS). Here, the formulation showed a safe profile as well as successful delivery to the lung epithelium with 88% GATA3 silencing in lung explants. These findings support the feasibility of Tf-Mel-PEI as siRNA delivery system for targeted gene knockdown in activated T cells as a potential novel therapy for allergic asthma.

Inhalable Formulations to Treat Non-Small Cell Lung Cancer (NSCLC): Recent Therapies and Developments

Cancer has been the leading cause of mortalities, with lung cancer contributing 18% to overall deaths. Non-small cell lung cancer (NSCLC) accounts for about 85% of all lung cancers. The primary form of therapy used to treat lung cancer still includes oral and systemic administration of drugs, radiotherapy, or chemotherapy. Some patients have to go through a regime of combination therapy. Despite being the only available form of therapy, their use is limited due to the adverse effects, toxicity, and development of resistance over prolonged use. This led to a shift and progressive evolution into using pulmonary drug delivery systems. Being a non-invasive method of drug-administration and allowing localized delivery of drugs to cancer cells, inhalable drug delivery systems can lead to lower dosing and fewer systemic toxicities over other conventional routes. In this way, we can increase the actual local concentration of the drug in lungs, which will ultimately lead to better antitumor therapy. Nano-based systems also provide additional diagnostic advantages during lung cancer treatment, including imaging, screening, and tracking. Regardless of the advantages, pulmonary delivery is still in the early stages of development and various factors such as pharmacology, immunology, and toxicology should be taken into consideration for the development of suitable inhalable nano-based chemotherapeutic drugs. They face numerous physiological barriers such as lung retention and efficacy, and could also lead to toxicity due to prolonged exposure. Nano-carriers with a sustained drug release mechanism could help in overcoming these challenges. This review article will focus on the various inhalable formulations for targeted drug delivery, including nano-based delivery systems such as lipids, liposome, polymeric and inorganic nanocarriers, micelles, microparticles and nanoaggregates for lung cancer treatment. Various devices used in pulmonary drug delivery loaded on various nano-carriers are also discussed in detail.

Preclinical Studies of the Nebulized Delivery of Liposomal Amphotericin B

Background: Intravenous liposomal amphotericin B (L-AMB) has accompanying side effects that may be diminished when administering an inhaled form. Delivery systems for inhaled or aerosolized L-AMB vary, and there has not been a recent comparison of available systems to date. Methods: We compared three differently designed nebulizer delivery systems for the inhaled delivery of L-AMB to determine the best combination of efficient lung dosing and treatment time. Aerosol size was measured using a Malvern Mastersizer, and five separate nebulizers were tested. For drug output measurements, a Harvard Lung was used, and aerosol was collected using HEPA filters. Results: Overall aerosol size characteristics were similar for all devices with volume median diameters in the 4-5 μm range. The highest inhaled dose was delivered by the AeroEclipse. The Aerogen and the AeroEclipse had similar predicted pulmonary doses, and the AeroEclipse had the highest pulmonary delivery rates. Conclusion: The AeroEclipse nebulizer may provide more efficient delivery in a shorter amount of time; however, human studies are warranted to assess the safety, tolerability, and efficacy of inhaled delivery of L-AMB from this system.

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.

Pharmacologic therapies of ARDS: From natural herb to nanomedicine

Acute respiratory distress syndrome (ARDS) is a common critical illness in respiratory care units with a huge public health burden. Despite tremendous advances in the prevention and treatment of ARDS, it remains the main cause of intensive care unit (ICU) management, and the mortality rate of ARDS remains unacceptably high. The poor performance of ARDS is closely related to its heterogeneous clinical syndrome caused by complicated pathophysiology. Based on the different pathophysiology phases, drugs, protective mechanical ventilation, conservative fluid therapy, and other treatment have been developed to serve as the ARDS therapeutic methods. In recent years, there has been a rapid development in nanomedicine, in which nanoparticles as drug delivery vehicles have been extensively studied in the treatment of ARDS. This study provides an overview of pharmacologic therapies for ARDS, including conventional drugs, natural medicine therapy, and nanomedicine. Particularly, we discuss the unique mechanism and strength of nanomedicine which may provide great promises in treating ARDS in the future.

A facile one-step jet-millingapproach for the preparation of proliposomal dry powder for inhalationaseffective delivery system for anti-TBtherapeutics

Objective: Physicochemical characterization and assessmentof aerosol dispersion performance of anti-TB proliposome dry powders for inhalation (DPIs) prepared using a single-step jet-milling (JM) approach. Significance: Conventional tuberculosis treatment involves isoniazid and rifampicin as first-line agents in extended oral multi-drug regimes. Liposomal DPIs are emerging as promising alternatives for targeted delivery of anti-TB agents to alveolar macrophages harboring Mycobacterium tuberculosis. However, traditional approaches for liposomal DPI preparation are tedious, time consuming and require sophisticated/expensive equipment. The proposed JM technique for preparation of proliposome DPIs could obviate these limitations and facilitate use of these drugs for more effective and safer treatment. Methods: Proliposome DPIs containing isoniazid and/or rifampicin, cholesterol and cholesterol sulfate were successfully prepared via JM (injection pressure, 7.4 bar; milling pressure, 3.68 bar). Their physicochemical, content uniformity, and in vitro aerosol dispersion performance were assessed using scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy, dynamic light scattering/Zeta potential, X-ray diffraction spectroscopy, thermogravimetric analysis, high performance liquid chromatography, and the Next Generation Impactor. Results: The DPIs exhibited consistent, spherically shaped, smooth particles. Drug particles were evenly distributed with acceptable content uniformity. Drug crystallinity was not significantly affected by milling and the formulations had minimal (<2.0%) water content. After reconstitution of theDPIs, the hydrodynamic size was about 370.9 - 556.2nm and charge was-12.3 - -47.3mV. Furthermore, the proliposome DPIs presented emitted dose (69.04 - 89.03%), fine particle fraction,< 4.4 µm (13.7 - 57.8%), and mass median aerodynamic diameter (<3.0 µm), which satisfied the requirements for deep lung delivery. Conclusion: The proposed approach was suitable for preparation of proliposome DPIs that could be deployed for local targeting of the lower respiratory tract for treatment of tuberculosis.

An innovative one step green supercritical CO2 process for the production of liposomes co-encapsulating both a hydrophobic and a hydrophilic compound for pulmonary administration

Budesonide and salbutamol-loaded liposomes were prepared using an innovative one step supercritical CO₂ method without any use of organic solvents. Liposomes composed of soybean phosphatidylcholine, cholesterol and PEGylated lipid (65/30/5% (m/m)) were produced with a size less than 200 nm, a PdI within the range of 0.3 and 0.35 and encapsulation efficiency for budesonide and salbutamol reaching to 94% and 40% respectively. The physical stability of the formulation was improved by optimizing a dry form by freeze-drying with trehalose in a 20:1 (trehalose:lipid) ratio and an increase in the percentage of PEGylated lipid from 5% to 15%. This dry form stored at 4°C maintains 90-110% of the initial concentration of active compounds. The concentration of budesonide and salbutamol after 15 weeks was 522.92 ± 73.01 µg/mL and 144.86 ± 31.22 µg/mL respectively. These concentrations are close to the concentrations of these molecules in the pharmaceutical products Pulmicort® (500 µg/mL of budesonide) and Ventolin® (100 µg/dose). The formulation tested on lung cells, allows a cell viability of 71 ± 6%, which is not significantly different from untreated cells.

Nanoparticle-Based Inhalation Therapy for Pulmonary Diseases

The lung is exposed to various pollutants and is the primary site for the onset of various diseases, including infections, allergies, and cancers. One possible treatment approach for such pulmonary diseases involves direct administration of therapeutics to the lung so as to maintain the topical concentration of the drug. Particles with nanoscale diameters tend to reach the pulmonary region. Nanoparticles (NPs) have garnered significant interest for applications in biomedical and pharmaceutical industries because of their unique physicochemical properties and biological activities. In this article, we describe the biological and pharmacological activities of NPs as well as summarize their potential in the formulation of drugs employed to treat pulmonary diseases. Recent advances in the use of NPs in inhalation chemotherapy for the treatment of lung diseases have also been highlighted.

CD44 receptor targeted nanoparticles augment immunity against tuberculosis in mice

We describe a role of CD44-mediated signaling during host-defense against tuberculosis (TB) using a mouse model of TB and studies in M. tuberculosis (Mtb) infected human macrophage (MФ). Liposomes targeting CD44 using thioaptamers (CD44TA-LIP) were designed and tested as new vaccines to boost host immunity in TB. CD44TA-LIP enhanced killing of Mtb in human MФ, which correlated with an increased production of pro-inflammatory cytokines IL-1β, TNF-α and IL-12. CD44TA-LIP activated MФ showed an enhanced MHC-II dependent antigen presentation to CD4 T-cells. Inhibition of cellular proliferation and cytoskeleton rearrangement pathways downstream of CD44 signaling abrogated CD44TA-LIP-induced antimicrobial effects. Blockade of inflammatory pathways also reduced antigen presentation by MФ and activation of CD4 T cells. Mtb infected MФ treated with CD44TA-LIP exhibited increased nitric oxide and HβD2 defensin peptide production. Among Mtb infected mice with increased lung and spleen loads of organisms, intranasal administration of CD44TA-LIP led to a ten-fold reduction of colony forming units of Mtb and elevated IFN-γ + CD4, effector, central and resident memory T cells. Biodistribution studies demonstrated that CD44TA-LIP preferentially accumulated in the lungs and were associated with CD11b + cells. CD44TA-LIP treated mice showed no weight loss or increased liver LDH levels. This study highlights the importance of CD44-mediated signaling in host-defense during TB and the therapeutic potential of CD44TA-LIP.

Inhibition of SARS-CoV-2 replication in the lung with siRNA/VIPER polyplexes

SARS-CoV-2 has been the cause of a global pandemic since 2019 and remains a medical urgency. siRNA-based therapies are a promising strategy to fight viral infections. By targeting a specific region of the viral genome, siRNAs can efficiently downregulate viral replication and suppress viral infection. However, to achieve the desired therapeutic activity, siRNA requires a suitable delivery system. The VIPER (virus-inspired polymer for endosomal release) block copolymer has been reported as promising delivery system for both plasmid DNA and siRNA in the past years. It is composed of a hydrophilic block for condensation of nucleic acids as well as a hydrophobic, pH-sensitive block that, at acidic pH, exposes the membrane lytic peptide melittin, which enhances endosomal escape. In this study, we aimed at developing a formulation for pulmonary administration of siRNA to suppress SARS-CoV-2 replication in lung epithelial cells. After characterizing siRNA/VIPER polyplexes, the activity and safety profile were confirmed in a lung epithelial cell line. To further investigate the activity of the polyplexes in a more sophisticated cell culture system, an air-liquid interface (ALI) culture was established. siRNA/VIPER polyplexes reached the cell monolayer and penetrated through the mucus layer secreted by the cells. Additionally, the activity against wild-type SARS-CoV-2 in the ALI model was confirmed by qRT-PCR. To investigate translatability of our findings, the activity against SARS-CoV-2 was tested ex vivo in human lung explants. Here, siRNA/VIPER polyplexes efficiently inhibited SARS-CoV-2 replication. Finally, we verified the delivery of siRNA/VIPER polyplexes to lung epithelial cells in vivo, which represent the main cellular target of viral infection in the lung. In conclusion, siRNA/VIPER polyplexes efficiently delivered siRNA to lung epithelial cells and mediated robust downregulation of viral replication both in vitro and ex vivo without toxic or immunogenic side effects in vivo, demonstrating the potential of local siRNA delivery as a promising antiviral therapy in the lung.

Development and Characterization of a Spray-Dried Inhalable Ciprofloxacin-Quercetin Co-Amorphous System

Spray drying is an increasingly used particle engineering technique for the production of dry powders for inhalation. However, the amorphous nature of most spray-dried particles remains a big challenge affecting both the chemical and the physical stability of the dried particles. Here, we study the possibility of producing co-amorphous ciprofloxacin-quercetin inhalable particles with improved amorphous stability compared to the individual amorphous drugs. Ciprofloxacin (CIP), a broad-spectrum antibiotic, was co-spray dried with quercetin (QUE), a compound with antibiofilm properties, from an ethanol-water co-solvent system at 2:1, 1:1 and 1:2 molar ratios to investigate the formation of co-amorphous CIP-QUE particles. Differential scanning colorimetry (DSC) and X-ray powder diffraction (XRPD) were used for solid-state characterization; dynamic vapor sorption (DVS) was used for investigating the moisture sorption behaviour. The intermolecular interaction was studied via solution-state nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy; the miscibility of the drugs was predicted via free energy calculations based on the Flory-Huggins interaction parameter (χ). A next generation impactor (NGI) was used to study the in vitro aerosol performance of the spray-dried powders. The physicochemical characteristics such as particle size, density, morphology, cohesion, water content and saturation solubility of the spray-dried powders were also studied. The co-spray-dried CIP-QUE powders prepared at the three molar ratios were predominantly amorphous. However, differences were observed between sample types. It was found that at a molar ratio of 1:1, CIP and QUE form a single co-amorphous system. However, increasing the molar ratio of either drug results in the formation of an additional amorphous phase, formed from the excess of the corresponding drug. Despite these differences, DVS showed that elevated humidity had a much lower influence on all three co-amorphous systems compared with the individual amorphous drugs. In vitro aerosolization study showed co-deposition of the two drugs from CIP-QUE powders with a desirable aerosol performance (ED ∼ 72% - 94%; FPF ∼ 48% - 65%) whereas QUE-only amorphous powder had an ED of 36% and a FPF of 22%. In summary, spray-dried CIP-QUE combinations resulted in co-amorphous systems with boosted stability and improved aerosol performance with the 1:1 molar ratio exhibiting the greatest improvement.

Aerosolizable Lipid-Nanovesicles Encapsulating Voriconazole Effectively Permeate Pulmonary Barriers and Target Lung Cells

The entire world has recently been witnessing an unprecedented upsurge in microbial lung infections. The major challenge encountered in treating the same is to ensure the optimum drug availability at the infected site. Aerosolization of antimicrobials, in this regard, has shown immense potential owing to their localized and targeted effect. Efforts, therefore, have been undertaken to systematically develop lung-phosphatidylcholine-based lipid nanovesicles of voriconazole for potential management of the superinfections like aspergillosis. LNVs, prepared by thin-film hydration method, exhibited a globule size of 145.4 ± 19.5 nm, polydispersity index of 0.154 ± 0.104 and entrapment efficiency of 71.4 ± 2.2% with improved in vitro antifungal activity. Aerodynamic studies revealed a microdroplet size of ≤5 μm, thereby unraveling its promise to target the physical barrier of lungs effectively. The surface-active potential of LNVs, demonstrated through Langmuir-Blodgett troughs, indicated their ability to overcome the biochemical pulmonary surfactant monolayer barrier, while the safety and uptake studies on airway-epithelial cells signified their immense potential to permeate the cellular barrier of lungs. The pharmacokinetic studies showed marked improvement in the retention profile of voriconazole in lungs following LNVs nebulization compared to pristine voriconazole. Overall, LNVs proved to be safe and effective delivery systems, delineating their distinct potential to efficiently target the respiratory fungal infections.

Strategies to Overcome Biological Barriers Associated with Pulmonary Drug Delivery

While the inhalation route has been used for millennia for pharmacologic effect, the biological barriers to treating lung disease created real challenges for the pharmaceutical industry until sophisticated device and formulation technologies emerged over the past fifty years. There are now several inhaled device technologies that enable delivery of therapeutics at high efficiency to the lung and avoid excessive deposition in the oropharyngeal region. Chemistry and formulation technologies have also emerged to prolong retention of drug at the active site by overcoming degradation and clearance mechanisms, or by reducing the rate of systemic absorption. These technologies have also been utilized to improve tolerability or to facilitate uptake within cells when there are intracellular targets. This paper describes the biological barriers and provides recent examples utilizing formulation technologies or drug chemistry modifications to overcome those barriers.

Inhaled Medicines: Past, Present, and Future

The purpose of this review is to summarize essential pharmacological, pharmaceutical, and clinical aspects in the field of orally inhaled therapies that may help scientists seeking to develop new products. After general comments on the rationale for inhaled therapies for respiratory disease, the focus is on products approved approximately over the last half a century. The organization of these sections reflects the key pharmacological categories. Products for asthma and chronic obstructive pulmonary disease include β -2 receptor agonists, muscarinic acetylcholine receptor antagonists, glucocorticosteroids, and cromones as well as their combinations. The antiviral and antibacterial inhaled products to treat respiratory tract infections are then presented. Two "mucoactive" products-dornase α and mannitol, which are both approved for patients with cystic fibrosis-are reviewed. These are followed by sections on inhaled prostacyclins for pulmonary arterial hypertension and the challenging field of aerosol surfactant inhalation delivery, especially for prematurely born infants on ventilation support. The approved products for systemic delivery via the lungs for diseases of the central nervous system and insulin for diabetes are also discussed. New technologies for drug delivery by inhalation are analyzed, with the emphasis on those that would likely yield significant improvements over the technologies in current use or would expand the range of drugs and diseases treatable by this route of administration. SIGNIFICANCE STATEMENT: This review of the key aspects of approved orally inhaled drug products for a variety of respiratory diseases and for systemic administration should be helpful in making judicious decisions about the development of new or improved inhaled drugs. These aspects include the choices of the active ingredients, formulations, delivery systems suitable for the target patient populations, and, to some extent, meaningful safety and efficacy endpoints in clinical trials.

Experimental Design Supported Liposomal Aztreonam Delivery: In Vitro Studies

Purpose: The present study focuses on a systemic approach to develop liposomal aztreonam as a promising dosage form for inhalation therapy in the treatment of pneumonia and explores the in-vitro antimicrobial and cell uptake efficacy. Methods: Liposomes were prepared by ethanol injection method using the lipids - soya phosphatidylcholine (SP) and cholesterol (CH). A central composite design (CCD) was employed to optimize the lipid composition to evaluate the effect on vesicle size, zeta potential and entrapment efficiency of the formulation. A numerical and graphical optimization was carried out to predict the optimized blend. The optimized formulation was characterized for vesicle size, surface charge, encapsulation, surface morphology, differential scanning calorimetry (DSC), powder X Ray Diffraction (PXRD), thermogravimetric analysis (TGA), in vitro diffusion, accelerated stability studies, antimicrobial studies on Pseudomonas aeruginosa NCIM 2200 and in vitro cell uptake studies. Results: The optimized formulation was found to have a particle size of 144 nm, a surface charge of -35 mV, with satisfactory drug entrapment. The surface morphology study proved the formation of nanosized vesicles. The drug release from liposomal matrix was biphasic in nature. The solid-state study revealed the reason for good encapsulation of drug. The moisture retention capacity was found to be minimum. The anti-microbial study revealed the potential antibacterial activity of the optimized formulation over the pure drug. The formulation was found to be safe on the epithelial cells and showed a marked increase in cellular uptake of aztreonam in a lipid carrier. Conclusion: It can be concluded that the optimized liposomal aztreonam could be considered as a promising approach for the delivery of aztreonam through inhalation.

Reparation of an Inflamed Air-Liquid Interface Cultured A549 Cells with Nebulized Nanocurcumin

The anti-inflammatory, antifibrotic and antimicrobial activities of curcumin (CUR) are missed because of its low solubility in aqueous media, low bioavailability, and structural lability upon oral intake. Soft nanoparticles such as nanoliposomes are not efficient as CUR carriers, since crystalline CUR is expelled from them to physiological media. Nanostructures to efficiently trap and increase the aqueous solubility of CUR are needed to improve both oral or nebulized delivery of CUR. Here we showed that SRA1 targeted nanoarchaeosomes (nATC) [1:0.4 w:w:0.04] archaeolipids, tween 80 and CUR, 155 ± 16 nm sized of −20.7 ± 3.3 z potential, retained 0.22 mg CUR ± 0.09 per 12.9 mg lipids ± 4.0 (~600 μM CUR) in front to dilution, storage, and nebulization. Raman and fluorescence spectra and SAXS patterns were compatible with a mixture of enol and keto CUR tautomers trapped within the depths of nATC bilayer. Between 20 and 5 µg CUR/mL, nATC was endocytosed by THP1 and A549 liquid–liquid monolayers without noticeable cytotoxicity. Five micrograms of CUR/mL nATC nebulized on an inflamed air–liquid interface of A549 cells increased TEER, normalized the permeation of LY, and decreased il6, tnfα, and il8 levels. Overall, these results suggest the modified pharmacodynamics of CUR in nATC is useful for epithelia repair upon inflammatory damage, deserving further deeper exploration, particularly related to its targeting ability.

Efficacy of Combined Rifampicin Formulations Delivered by the Pulmonary Route to Treat Tuberculosis in the Guinea Pig Model

Liposomes, as vehicles alone or in combination with rifampicin (RIF) microparticles (RMs), were evaluated as vehicles to enhance the permeation of RIF into granulomas. RIF liposomes (RLs) were extruded through a 0.1 µm polypropylene membrane. RMs were prepared by the solvent evaporation method. Four weeks after infection, guinea pigs (GPs) were assigned to groups treated with a combination of RM-RLs or RLs alone. RLs were nebulized after extrusion whereas RMs were suspended in saline and nebulized to GPs in a nose-only inhalation chamber. Necropsy was performed after the treatment; the lungs and spleen were resected for bacteriology. RLs had mean diameters of 137.1 ± 33.7 nm whereas RMs had a projected area diameter of 2.48 µm. The volume diameter of RMs was 64 ± 1 µm, indicating that RMs were aggregated. The treatment of TB-infected GPs with RLs significantly reduced their lung bacterial burden and wet spleen weight compared with those treated with blank liposomes. The treatment of TB-infected animals with RM-RLs also reduced their lung bacterial burden and wet spleen weight even though these reductions were not statistically different. Based on these results, the permeation of RIF into granulomas appears to be enhanced when encapsulated into liposomes delivered by the pulmonary route.

Pulmonary Delivery of Anticancer Drugs via Lipid-Based Nanocarriers for the Treatment of Lung Cancer: An Update

Lung cancer (LC) is the leading cause of cancer-related deaths, responsible for approximately 18.4% of all cancer mortalities in both sexes combined. The use of systemic therapeutics remains one of the primary treatments for LC. However, the therapeutic efficacy of these agents is limited due to their associated severe adverse effects, systemic toxicity and poor selectivity. In contrast, pulmonary delivery of anticancer drugs can provide many advantages over conventional routes. The inhalation route allows the direct delivery of chemotherapeutic agents to the target LC cells with high local concertation that may enhance the antitumor activity and lead to lower dosing and fewer systemic toxicities. Nevertheless, this route faces by many physiological barriers and technological challenges that may significantly affect the lung deposition, retention, and efficacy of anticancer drugs. The use of lipid-based nanocarriers could potentially overcome these problems owing to their unique characteristics, such as the ability to entrap drugs with various physicochemical properties, and their enhanced permeability and retention (EPR) effect for passive targeting. Besides, they can be functionalized with different targeting moieties for active targeting. This article highlights the physiological, physicochemical, and technological considerations for efficient inhalable anticancer delivery using lipid-based nanocarriers and their cutting-edge role in LC treatment.

Liposomal drug delivery to manage nontuberculous mycobacterial pulmonary disease and other chronic lung infections

Nontuberculous mycobacterial (NTM) pulmonary disease is a chronic respiratory infection associated with declining lung function, radiological deterioration and significantly increased morbidity and mortality. Patients often have underlying lung conditions, particularly bronchiectasis and COPD. NTM pulmonary disease is difficult to treat because mycobacteria can evade host defences and antimicrobial therapy through extracellular persistence in biofilms and sequestration into macrophages. Management of NTM pulmonary disease remains challenging and outcomes are often poor, partly due to limited penetration of antibiotics into intracellular spaces and biofilms. Efficient drug delivery to the site of infection is therefore a key objective of treatment, but there is high variability in lung penetration by antibiotics. Inhalation is the most direct route of delivery and has demonstrated increased efficacy of antibiotics like amikacin compared with systemic administration. Liposomes are small, artificial, enclosed spherical vesicles, in which drug molecules can be encapsulated to provide controlled release, with potentially improved pharmacokinetics and reduced toxicity. They are especially useful for drugs where penetration of cell membranes is essential. Inhaled delivery of liposomal drug solutions can therefore facilitate direct access to macrophages in the lung where the infecting NTM may reside. A range of liposomal drugs are currently being evaluated in respiratory diseases.

Liposome-encapsulated antibiotics can optimise respiratory disease treatment. Amikacin liposomal inhalation suspension is effective in nontuberculous mycobacterial pulmonary disease that has failed to convert following oral guideline-based therapy.https://bit.ly/3f3ixIu

Inhalable liposomes for treating lung diseases: clinical development and challenges

Inhalation delivery of liposomal drugs has distinct advantages for the treatment of pulmonary diseases. Inhalable liposomes of several drugs are currently undergoing clinical trials for a range of indications in the lungs. Herein, general principles of pulmonary delivery as well as the clinical development of inhalable liposomal drugs are reviewed.

Storage stability of inhalable, controlled-release powder formulations of ciprofloxacin nanocrystal-containing liposomes

Novel inhalable and controlled release powder formulations of ciprofloxacin nanocrystals inside liposomes (CNL) were recently developed. In the present study, the storage stability of CNL powders consisting of lyoprotectant (i.e. sucrose or lactose), lipids, ciprofloxacin (CIP), and magnesium stearate or isoleucine was investigated. These powders were produced by spray drying, collected in a dry box at <15% relative humidity (RH), then stored at room temperature and either 4 or 20 %RH. Liposomal integrity, CIP encapsulation efficiency (EE), in vitro drug release (IVR), aerosol performance, and solid-state properties were examined over six months. Sucrose CNL powder exhibited consistent liposomal integrity, aerosol performance, and controlled release of CIP over six months of storage at 4 %RH. However, storage of the powder at 20 %RH for the same period caused sucrose crystallization and consequently a significant drop in EE and aerosol performance (p-values < 0.05), along with the IVR of CIP becoming similar to that of the non-crystalline CIP liposomal dispersions (f2 > 50). Lactose CNL maintained superior aerosol performance over the six months irrespective of the storage RH. However, liposomal instability occurred at both RHs within the first month of storage with a significant drop in EE and an increase in liposome size (p-values < 0.05). Moreover, the IVR assay of CIP from lactose CNL showed a less controlled release and a substantial difference (f2 < 50) from its initial value after six months regardless of the storage RHs. In conclusion, dry powder inhalers of CNL were physiochemically stable in sucrose lyoprotectant when stored below 4 %RH at room temperature for six months.

Robustness of aerosol delivery of amikacin liposome inhalation suspension using the eFlow® Technology

The purpose of these studies was to understand the effect on product performance of batch-to-batch variability in both the amikacin liposome inhalation suspension (ALIS) formulation and its delivery device, the Lamira® nebulizer system, designed and manufactured by PARI (PARI Pharma GmbH, Munich, Germany). Three batches of ALIS spanning a range of lipid concentrations (43, 48 and 54 mg/mL) were tested with nine PARI inhalation devices that varied within the production process of the vibrating membrane with respect to hole geometry. Three hole geometry clusters were built including a geometry close to the mean geometry (median) and two geometries deviating from the mean geometry with smaller (smaller) and larger (larger) holes. The output parameters included the nebulization rate, the aerosol droplet size distribution, the liposome vesicle size post-nebulization, and the fraction of amikacin that remained encapsulated post-nebulization. Across the 27 experimental combinations of three formulation batches and nine devices, the nebulization time varied between 12 and 15 min with the fastest nebulization rate occurring with the combination of low lipid concentration and larger hole geometry (0.68 g/min) and the slowest nebulization rate occurring with the combination of high lipid concentration and the smaller hole geometry (0.59 g/min). The mean liposome vesicle size post-nebulization ranged from 269 to 296 nm across all experimental combinations which was unchanged from the control samples (276-292 nm). While all three batches contained > 99% encapsulated amikacin prior to nebulization, the nebulization process resulted in a consistent generation of ~ 35% unencapsulated amikacin (range: 33.8% to 37.6%). There was no statistically significant difference in the generated aerosol particle size distributions. The mass median aerodynamic diameters (MMAD) ranged from 4.78 µm to 4.98 µm, the geometric standard deviations (GSD) ranged from 1.61 to 1.66, and the aerosol fine particle fraction (FPF < 5 µm) ranged from 50.3 to 53.5%. The emitted dose (ED) of amikacin ranged from 473 to 523 mg (80.2 to 89.3% of loaded dose (LD)) and the fine particle dose (FPD < 5 µm) ranged from 244 to 278 mg (41.4 to 47.1% of label claim (LC)). In conclusion, while variations in the lipid concentration of the ALIS formulation and the device hole geometry had a small but significant impact on nebulization time, the critical aerosol performance parameters were maintained and remained within acceptable limits.

Influence of liposomes composition on their stability during the nebulization process by vibrating mesh nebulizer

In this study, three different molecules (cholesterol, phosphatidic acid, and polyethylene glycol) were used for the stabilization of liposomes during the nebulization process. The purpose of this article is to answer the question of whether the change in the composition of liposomes affected the parameters of generated aerosol and whether the nebulization process affected observed properties of liposomes. Firstly, liposomes with different composition were prepared and their properties were checked by dynamic and electrophoretic light scattering. The membrane properties were measured by fluorescence spectroscopy - especially generalized polarization (Laurdan) and anisotropy (Diphenylhexatriene). The same characteristic of liposomes was measured after the nebulization by vibrating mesh nebulizer. Cholesterol was capable of liposome stabilization because of increased membrane fluidity. The membrane properties of the outer and inner parts were not influenced by the nebulization process. Electrostatic stabilization was successful for the lowest concentration of phosphatidic acid, but after the nebulization process the hydration of the membrane outer part was changed. Higher amount of PEG needs to be added for successful steric stabilization. The nebulization process of the two lowest concentrations of PEG slightly influenced immobilized water and the rigidity of inner part of the membrane (especially around the phase transition temperature).

Formulation of chitosan coated nanoliposomes for the oral delivery of colistin sulfate: in vitro characterization, 99mTc-radiolabeling and in vivo biodistribution studies

Colistin sulfate is a very important antibiotic for the treatment of multidrug-resistant Gram-negative infections. Unfortunately, it has low oral bioavailability and several side effects following parenteral administration. The present study aims to develop chitosan-coated colistin nanoliposomes to improve the stability in the gastrointestinal tract and to enhance the oral delivery of colistin. The chitosan-coated colistin nanoliposomes were obtained via thin-film evaporation and electrostatic deposition methods using either Span 60, Tween 65 or Tween 80 as surfactants with different cholesterol: surfactant: soya lecithin ratios. The influence of systems variables was further characterized by vesicle size analysis, zeta potential (ZP), poly dispersibility index (PDI), and also their entrapment efficiency percentage (EE %) was evaluated. Various systems were formed with vesicle sizes in the nano-range, 155.64 ± 12.53 nm to 315.64 ± 15.90 nm, and EE % of 45.2 ± 2.9% to 81.8 ± 2.9%. Moreover, the ZP value of the prepared nanoliposomes switched from a negative to a positive value after chitosan coating. To track the released colistin in vivo, technetium 99m (^99mTc) was incorporated into the optimum system (S-3) system via direct coupling with colistin. Chitosan-coated ^99mTc-colistin nanoliposome, ^99mTc-colistin suspension, and ^99mTc-chitosan-coated nanoliposomes (placebo) were administered orally into bacterial infection (Escherichia coli) bearing mice. The biodistribution results showed that chitosan-coated nanoliposome significantly enhanced the bioavailability of colistin compared to colistin suspension (the commercially available). Moreover, the system effectively improved the localization of colistin at the infected muscle. In conclusion, this approach offers a promising tool for enhanced oral delivery of colistin.

Development of Inhalable Nanostructured Lipid Carriers for Ciprofloxacin for Noncystic Fibrosis Bronchiectasis Treatment

PURPOSE

Ciprofloxacin (CIP) has poor lung targeting after oral inhalation. This study developed optimized inhalable nanostructured lipid carriers (NLCs) for CIP to enhance deposition and accumulation in deeper parts of the lungs for treatment of noncystic fibrosis bronchiectasis (NCFB).

METHODS

NLC formulations based on stearic acid and oleic acid were successfully prepared by hot homogenization and in vitro-characterized. CIP-NLCs were formulated into nanocomposite micro particles (NCMPs) for administration in dry powder inhalation (DPI) formulations by spray-drying (SD) using different ratios of chitosan (CH) as a carrier. DPI formulations were evaluated for drug content and in vitro deposition, and their mass median aerodynamic diameter (MMAD), fine particle fraction (FPF), fine particle dose (FPD), and emitted dose (ED) were determined.

RESULTS

The CIP-NLCs were in the nanometric size range (102.3 ± 4.6 nm), had a low polydispersity index (0.267 ± 0.12), and efficient CIP encapsulation (98.75% ± 0.048%), in addition to a spherical and smooth shape with superior antibacterial activity. The in vitro drug release profile of CIP from CIP-NLCs showed 80% release in 10 h. SD of CIP-NLCs with different ratios of CH generated NCMPs with good yield (>65%). The NCMPs had a corrugated surface, but with increasing lipid:CH ratios, more spherical, smooth, and homogenous NCMPs were obtained. In addition, there was a significant change in the FPF with increasing lipid:CH ratios (P ˂ 0.05). NCMP-1 (lipid:CH = 1:0.5) had the highest FPD (45.0 µg) and FPF (49.2%), while NCMP-3 (lipid:CH = 1:1.5) had the lowest FPF (37.4%). All NCMP powders had an MMAD in the optimum size range of 3.9-5.1 μm.

CONCLUSION

Novel inhalable CIP NCMP powders are a potential new approach to improved target ability and delivery of CIP for NCFB treatment.

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

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

Optimization of inhalable liposomal powder formulations and evaluation of their in vitro drug delivery behavior in Calu-3 human lung epithelial cells

Inhalation therapy has advantages for the treatment of multidrug resistant bacterial lung infections with high drug concentrations at the infection sites in the airways and reduced systemic exposure. We have developed liposomal formulations for pulmonary delivery of synergistic ciprofloxacin (Cipro) and colistin (Col) as the potential candidate for treatment of lung infections caused by multidrug resistant Gram-negative bacteria. This study aims to: (1) further optimize the powder formulation by adding drying stabilizers (polyvinyl pyrrolidone or poloxamer) to protect the liposomes during spray-freeze-drying; (2) evaluate the transport and cellular uptake of drugs in a human lung epithelial Calu-3 cell model. The liposomal powder formulations were produced using the ultrasonic spray-freeze-drying technique. The optimal formulation (F5) used mannitol (8% w/v) and sucrose (2% w/v) as the internal lyoprotectants. Adding external lyoprotectants/aerosolization enhancers (i.e. 8% w/v mannitol, 2% w/v sucrose and 1%, w/w PVP 10) produced the superior rehydrated EE values of ciprofloxacin and colistin (50.2 ± 0.9% for Cipro and 37.8 ± 1.2% for Col) as well as satisfactory aerosol performance (FPF: 34.2 ± 0.8% for Cipro and 33.6 ± 0.9% for Col). The cytotoxicity study indicated that F5 with the colistin concentration at 50 μg/mL and ciprofloxacin at 200 μg/mL was not cytotoxic to human lung epithelial Calu-3 cells. The intracellular uptake of ciprofloxacin was concentration-dependent in Calu-3 cells and the uptake of A-B was more than that of B-A for all samples (p < 0.05). This study demonstrates that co-delivery of ciprofloxacin and colistin in a single liposome can lower the transport capability of both drugs across the Calu-3 cell monolayer and their accumulation in the cells. These findings indicate that co-loaded liposomal powder of ciprofloxacin and colistin is a promising potential treatment for respiratory infections caused by multidrug resistant Gram-negative bacteria.

Preclinical Development of Orally Inhaled Drugs (OIDs)-Are Animal Models Predictive or Shall We Move Towards In Vitro Non-Animal Models?

Respiratory diseases constitute a huge burden in our society, and the global respiratory drug market currently grows at an annual rate between 4% and 6%. Inhalation is the preferred administration method for treating respiratory diseases, as it: (i) delivers the drug directly at the site of action, resulting in a rapid onset; (ii) is painless, thus improving patients' compliance; and (iii) avoids first-pass metabolism reducing systemic side effects. Inhalation occurs through the mouth, with the drug generally exerting its therapeutic action in the lungs. In the most recent years, orally inhaled drugs (OIDs) have found application also in the treatment of systemic diseases. OIDs development, however, currently suffers of an overall attrition rate of around 70%, meaning that seven out of 10 new drug candidates fail to reach the clinic. Our commentary focuses on the reasons behind the poor OIDs translation into clinical products for the treatment of respiratory and systemic diseases, with particular emphasis on the parameters affecting the predictive value of animal preclinical tests. We then review the current advances in overcoming the limitation of animal animal-based studies through the development and adoption of in vitro, cell-based new approach methodologies (NAMs).

Lipid-based nanoparticle formulations for small molecules and RNA drugs

Introduction: Liposomes and lipid-based nanoparticles (LNPs) effectively deliver cargo molecules to specific tissues, cells, and cellular compartments. Patients benefit from these nanoparticle formulations by altered pharmacokinetic properties, higher efficacy, or reduced side effects. While liposomes are an established delivery option for small molecules, Onpattro® (Sanofi Genzyme, Cambridge, MA) is the first commercially available LNP formulation of a small interfering ribonucleic acid (siRNA). Areas covered: This review article summarizes key features of liposomal formulations for small molecule drugs and LNP formulations for RNA therapeutics. We describe liposomal formulations that are commercially available or in late-stage clinical development and the most promising LNP formulations for ASOs, siRNAs, saRNA, and mRNA therapeutics. Expert opinion: Similar to liposomes, LNPs for RNA therapeutics have matured but still possess a niche application status. RNA therapeutics, however, bear an immense hope for difficult to treat diseases and fuel the imagination for further applications of RNA drugs. LNPs face similar challenges as liposomes including limitations in biodistribution, the risk to provoke immune responses, and other toxicities. However, since properties of RNA molecules within the same group are very similar, the entire class of therapeutic molecules would benefit from improvements in a few key parameters of the delivery technology.

Inhalable liposomal powder formulations for co-delivery of synergistic ciprofloxacin and colistin against multi-drug resistant gram-negative lung infections

The aim of this study was to design and characterize dry powder inhaler formulations of ciprofloxacin and colistin co-loaded liposomes prepared by the ultrasonic spray-freeze-drying (USFD) technique. Liposomal formulations and powder production parameters were optimized to achieve optimal characteristics and in-vitro performance such as encapsulation efficiency (EE), particle size, particle distribution index (PDI), fine particle fraction (FPF), emitted dose (ED) and in vitro antibacterial activity. The formulation (F6) with the mannitol (5% w/v) as the internal lyoprotectant and sucrose (5%, w/v), mannitol (10%, w/v) and leucine (5%, w/w) as the external lyoprotectants/aerosolization enhancers showed an optimal rehydrated EE values of ciprofloxacin and colistin (44.9 ± 0.9% and 47.0 ± 0.6%, respectively) as well as satisfactory aerosol performance (FPF: 45.8 ± 2.2% and 43.6 ± 1.6%, respectively; ED: 97.0 ± 0.5% and 95.0 ± 0.6%, respectively). For the blank liposomes, there was almost no inhibitory effect on the cell proliferation in human lung epithelial A549 cells, showing that the lipid materials used in the liposome formulation is safe for use in pulmonary drug delivery. The cytotoxicity study demonstrated that the optimized liposomal formulation (F6) was not cytotoxic at least at the drug concentrations of colistin 5 μg/mL and ciprofloxacin 20 μg/mL. Colistin (2 mg/L) monotherapy showed no antibacterial effect against P. aeruginosa H131300444 and H133880624. Ciprofloxacin (8 mg/L) monotherapy showed moderate bacterial killing for both clinical isolates; however, regrowth was observed in 6 h for P. aeruginosa H133880624. The liposomal formulation displayed superior antibacterial activity against clinical isolates of Pseudomonas aeruginosa H131300444 and P. aeruginosa H133880624 compared to each antibiotic per se. These results demonstrate that the liposomal powder formulation prepared by USFD could potentially be a pulmonary delivery system for antibiotic combination to treat multi-drug resistant Gram-negative lung infections.

Formation of ciprofloxacin nanocrystals within liposomes by spray drying for controlled release via inhalation

The present study was conducted to harness spray drying technology as a novel method of producing Ciprofloxacin nanocrystals inside liposomes (CNL) for inhalation delivery. Liposomal ciprofloxacin dispersions were spray dried with sucrose as a lyoprotectant in different mass ratios (0.5:1, 1:1 and 2:1 sucrose to lipids), along with 2% w/w magnesium stearate and 5% w/w isoleucine as aerosolization enhancers. Spray drying conditions were: inlet air temperature 50 °C, outlet air temperature 33-35 °C, atomizer rate 742 L/h and aspirator 35 m³/h. After spray drying, the formation of ciprofloxacin nanocrystals inside the liposomes was confirmed by cryo- transmission electron microscopy. The physiochemical characteristics of the spray dried powder (particle size, morphology, crystallinity, moisture content, drug encapsulation efficiency (EE), in vitro aerosolization performance and drug release) were determined. The EE of the liposomes was found to vary between 44 and 87% w/w as the sucrose content was increased from 25 to 57% w/w. The powders contained partially crystalline particles with a volume median diameter of ~1 µm. The powders had low water content (~2% wt.) and were stable at high relative humidity. Aerosol delivery using the Osmohaler® inhaler at a flow rate of 100 L/min produced an aerosol fine particle fraction (% wt. <5 µm) of 58-64%. The formulation with the highest sucrose content (2:1 w/w sucrose to lipid) demonstrated extended ciprofloxacin release from liposomes (80% released within 7 h) in comparison to the original liquid formulation (80% released within 2 h). In conclusion, a stable and inhalable CNL powder with controlled drug release was successfully prepared by spray drying.