Engineering the right formulation for enhanced drug delivery

Dandelion inspired microparticles with highly efficient drug delivery to deep lung

Active pharmaceutical ingredient (API) embedded dry powder for inhalation (AeDPI) shows higher drug loading and delivery dose for directly treating various lung infections. Inspired by the dandelion, we propose a novel kind of AeDPI microparticle structure fabricated by spray freeze drying technology, which would potentially enhance the alveoli deposition efficiency. When inhaling, such microparticles are expected to be easily broken-up into fragments containing API that acts as 'seed' and could be delivered to alveoli aided by the low density 'pappus' composed of excipient. Herein, itraconazole (ITZ), a first-line drug for treating pulmonary aspergillosis, was selected as model API. TPGS, an amphiphilic surfactant, was used to achieve stable primary ITZ nanocrystal (INc) suspensions for spray freeze drying. A series of microparticles were prepared, and the dandelion-like structure was successfully achieved. The effects of feed liquid compositions and freezing parameters on the microparticle size, morphology, surface energy, crystal properties and in vitro aerosol performance were systematically investigated. The optimal sample (SF(-50)D-INc7Leu3-2) in one-way experiment showed the highest fine particle fraction of ∼ 68.96 % and extra fine particle fraction of ∼ 36.87 %, equivalently ∼ 4.60 mg and ∼ 2.46 mg could reach the lung and alveoli, respectively, when inhaling 10 mg dry powders. The response surface methodology (RSM) analysis provided the optimized design space for fabricating microparticles with higher deep lung deposition performance. This study demonstrates the advantages of AeDPI microparticle with dandelion-like structure on promoting the delivery efficiency of high-dose drug to the deep lung.

Understanding the role of swirling flow in dry powder inhalers: Implications for design considerations and pulmonary delivery

Dry powder inhalers (DPIs) are widely employed to treat respiratory diseases, offering numerous advantages such as high dose capacity and stable formulations. However, they usually face challenges in achieving sufficient pulmonary drug delivery and minimizing excessive oropharyngeal deposition. This review provides a new viewpoint to address these challenges by focusing on the role of swirling flow, a crucial yet under-researched aspect that induces strong turbulence. In the review, we comprehensively discuss both key classic designs (tangential inlet, swirling chamber, grid mesh, and mouthpiece) and innovative designs in inhalers, exploring how the induced swirling flow initiates powder dispersion and promotes delivery efficiency. Valuable design considerations to effectively coordinate inhalers with formulations and patients are also provided. It is highlighted that the delicate manipulation of swirling flow is essential to maximize benefits. By emphasizing the role of swirling flow and its potential application, this review offers promising insights for advancing DPI technology and optimizing therapeutic outcomes in inhaled therapy.

Lipid polymer hybrid nanoparticles against lung cancer and their application as inhalable formulation

Lung cancer is a leading cause of global cancer mortality, often treated with chemotherapeutic agents. However, conventional approaches such as oral or intravenous administration of drugs yield low bioavailability and adverse effects. Nanotechnology has unlocked new gateways for delivering medicine to their target sites. Lipid-polymer hybrid nanoparticles (LPHNPs) are one of the nano-scaled delivery platforms that have been studied to exploit advantages of liposomes and polymers, enhancing stability, drug loading, biocompatibility and controlled release. Pulmonary administration of drug-loaded LPHNPs enables direct lung deposition, rapid onset of action and heightened efficacy at low doses of drugs. In this manuscript, we will review the potential of LPHNPs in management of lung cancer through pulmonary administration.

Highly Drug-Loaded Nanoaggregate Microparticles for Pulmonary Delivery of Cyclosporin A

Introduction

Nanoparticles have the advantages of improving the solubility of poorly water-soluble drugs, facilitating the drug across biological barriers, and reducing macrophage phagocytosis in pulmonary drug delivery. However, nanoparticles have a small aerodynamic particle size, which makes it difficult to achieve optimal deposition when delivered directly to the lungs. Therefore, delivering nanoparticles to the lungs effectively has become a popular research topic.

Methods

Nanoaggregate microparticles were used as a pulmonary drug delivery strategy for the improvement of the bioavailability of cyclosporine A (CsA). The nanoaggregate microparticles were prepared with polyvinyl pyrrolidone (PVP) as the excipient by combining the anti-solvent method and spray drying process. The physicochemical properties, aerodynamic properties, in vivo pharmacokinetics and inhalation toxicity of nanoaggregate microparticles were systematically evaluated.

Results

The optimal nanoparticles exhibited mainly spherical shapes with the particle size and zeta potential of 180.52 nm and -19.8 mV. The nanoaggregate microparticles exhibited irregular shapes with the particle sizes of less than 1.6 µm and drug loading (DL) values higher than 70%. Formulation NM-2 as the optimal nanoaggregate microparticles was suitable for pulmonary drug delivery and probably deposited in the bronchiole and alveolar region, with FPF and MMAD values of 89.62% and 1.74 μm. In addition, inhaled NM-2 had C max and AUC0-∞ values approximately 1.7-fold and 1.8-fold higher than oral cyclosporine soft capsules (Neoral®). The inhalation toxicity study suggested that pulmonary delivery of NM-2 did not result in lung function damage, inflammatory responses, or tissue lesions.

Conclusion

The novel nanoaggregate microparticles for pulmonary drug delivery could effectively enhance the relative bioavailability of CsA and had great potential for clinical application.

Spray freeze dried cannabidiol with dipalmitoylphosphatidylcholine (DPPC) for inhalation and solubility enhancement

Pulmonary delivery is an efficient route of administration to deliver cannabidiol (CBD) due to the high bioavailability and fast onset of action. The major formulation challenge is the poor aqueous solubility of CBD. This study aimed to produce inhalable CBD powders with enhanced solubility and characterise their solid-state properties. CBD was spray freeze dried with mannitol or trehalose dihydrate with and without dipalmitoylphosphatidylcholine (DPPC). All four powders had acceptable yields at > 70 % with porous and spherical particles. The two crystalline mannitol powders contained less residual solvent than both amorphous trehalose ones. The addition of DPPC did not affect the crystallinity and residual solvent level of the powders. Instead, DPPC made the particles more porous, decreased the particle size from 19-23 µm to 11-13 µm, and increased CBD solubility from 0.36 µg/mL to over 2 µg/mL. The two DPPC powders were dispersed from a low resistance RS01 inhaler, showing acceptable aerosol performance with emitted fractions at 91-93 % and fine particle fractions < 5 µm at 34-43 %. These formulations can be used as a platform to deliver CBD and other cannabinoids by inhalation.

Essential considerations towards development of effective nasal antibiotic formulation: features, strategies, and future directions

INTRODUCTION

Intranasal antibiotic products are gaining popularity as a promising method of administering antibiotics, which provide numerous benefits, e.g. enhancing drug bioavailability, reducing adverse effects, and potentially minimizing resistance threats. However, some issues related to the antibiotic substances and nasal route challenges must be addressed to prepare effective formulations.

AREAS COVERED

This review focuses on the valuable points of nasal delivery as an alternative route for administering antibiotics, coupled with the challenges in the nasal cavity that might affect the formulations. Moreover, this review also highlights the application of nasal delivery to introduce antibiotics for local therapy, brain targeting, and systemic effects that have been conducted. In addition, this viewpoint provides strategies to maintain antibiotic stability and several crucial aspects to be considered for enabling effective nasal formulation.

EXPERT OPINION

In-depth knowledge and understanding regarding various key considerations with respect to the antibiotic substances and nasal route delivery requirement in preparing effective nasal antibiotic formulation would greatly improve the development of nasally administered antibiotic products, enabling better therapeutic outcomes of antibiotic treatment and establishing appropriate use of antibiotics, which in turn might reduce the chance of antibiotic resistance and enhance patient comfort.

Inhalable paclitaxel nanoagglomerate dry powders for lung cancer chemotherapy: Design of experiments-guided development, characterization and in vitro evaluation

Conventional intravenous chemotherapy for lung cancer frequently results in inefficient drug penetration into primary lung tumors and severe systemic toxicities. This study reports the development of inhalable paclitaxel (PTX) nanoagglomerate dry powders (PTX-NADP) for enhanced pulmonary delivery of PTX chemotherapy to lung tumors using full factorial Design of Experiments. PTX nanoparticles were fabricated by flash nanoprecipitation with the aid of N-polyvinylpyrrolidone (PVP) and curcumin (CUR) as stabilizer and co-stabilizer respectively, and subsequently agglomerated into inhalable dry powders via co-spray drying with methylcellulose. The optimized PTX-NADP formulation exhibited acceptable aqueous redispersibility (redispersibility index = 1.17 ± 0.02) into ∼ 150 nm nanoparticles and superb in vitro aerosol performance [mass median aerodynamic diameter (MMAD) = 1.69 ± 0.05 µm and fine particle fraction (FPF) of 70.89 ± 1.72 %] when dispersed from a Breezhaler® at 90 L/min. Notably, adequate aerosolization (MMAD < 3.5 µm and FPF > 40 %) of the optimized formulation was maintained when dispersed at reduced inspiratory flow rates of 30 - 60 L/min. Redispersed PTX nanoparticles from PTX-NADP demonstrated enhanced in vitro antitumor efficacy and cellular uptake in A549 lung adenocarcinoma cells without compromising tolerability of BEAS-2B normal lung epithelial cells towards PTX chemotherapy. These findings highlight the potential of inhaled PTX-NADP therapy to improve therapeutic outcomes for lung cancer patients with varying levels of pulmonary function impairment.

Natural Products-Based Inhaled Formulations for Treating Pulmonary Diseases

Given the unique physiological and pathological characteristics of the lung, the direct, inhalable route is more conducive to pulmonary drug delivery and disease control than traditional systemic drug delivery, significantly circumventing drug loss, off-target effects, systemic and organ toxicity, etc., and is widely regarded as the preferred regimen for pulmonary drug delivery. However, very few lung diseases are currently treated with the preferred inhaled formulations, such as asthma, chronic obstructive pulmonary disease and pulmonary hypertension. And there is a lack of appropriate inhaled formulations for other critical lung diseases, such as lung cancer and pulmonary fibrosis, due to the fact that the physicochemical properties of the drugs and their pharmacokinetic profiles do not match the physiology of the lung, and conventional inhalation devices are unable to deliver them to the specific parts of the lung. Phytochemicals of natural origin, due to their wide availability and clear safety profile, hold great promise for the preparation of inhalable formulations to improve the current dilemma in the treatment of lung diseases. In particular, the preparation of inhalable formulations based on nano- and microparticulate carriers for drug delivery to deep lung tissues, which overcome the shortcomings of conventional inhalation therapies while targeting the drug activity directly to a specific part of the lung, may be the best approach to change the current dilemma of lung disease treatment. In this review, we discuss recent advances in nano- and micron-carrier-based inhalation formulations for the delivery of natural products for the treatment of pulmonary diseases, which may represent an opportunity for practical clinical translation of natural products.

Inhaled JAK Inhibitor GDC-0214 Nanoaggregate Powder Exhibits Improved Pharmacokinetic Profile in Rats Compared to the Micronized Form: Benefits of Thin Film Freezing

Asthma is a common chronic disease affecting the airways in the lungs. The receptors of allergic cytokines, including interleukin (IL)-4, IL-5, and IL-13, trigger the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, which involves the pathogenesis of asthma. GDC-0214 is a JAK inhibitor that was developed as a potent and selective target for the treatment of asthma, specifically targeting the lungs. While inhaled GDC-0214 is a promising novel treatment option against asthma, improvement is still needed to achieve increased potency of the powder formulation and a reduced number of capsules containing powder to be inhaled. In this study, high-potency amorphous powder formulations containing GDC-0214 nanoaggregates for dry powder inhalation were developed using particle engineering technology, thin film freezing (TFF). A high dose per capsule was successfully achieved by enhancing the solubility of GDC-0214 and powder conditioning. Lactose and/or leucine as excipients exhibited optimum stability and aerosolization of GDC-0214 nanoaggregates, and aerosolization of the dose was independent of air flow through the device between 2 and 6 kPa pressure drops. In the rat PK study, formulation F20, which contains 80% GDC-0214 and 20% lactose, resulted in the highest AUC0-24h in the lungs with the lowest AUC0-24h in the plasma that corresponds to a 4.8-fold higher ratio of the lung-to-plasma exposures compared to micronized crystalline GDC-0214 powder administered by dry powder inhalation. Therefore, GDC-0214 nanoaggregates produced by TFF provided an improved dry powder for inhalation that can lead to enhanced therapeutic efficacy with a lower risk of systemic toxicity.

Inhalable spray-dried polycaprolactone-based microparticles of Sorafenib Tosylate with promising efficacy on A549 cells

The study developed and evaluated Sorafenib Tosylate (SRT)-loaded polymeric microparticles (MPs) using biodegradable polymer polycaprolactone (PCL) as a potential inhalable carrier for NSCLC. MPs were prepared by spray-drying an oil-in-water (o/w) emulsion. The optimized MPs demonstrated excellent flowability, particle size of 2.84 ± 0.5 μm, zeta potential of -14.0 ± 1.5 mV, and 85.08 ± 5.43% entrapment efficiency. ATR-FTIR/DSC studies revealed a lack of characteristic peaks of the crystalline drug signifying good entrapment of the drug. MPs were spherical and uniform in SEM pictures. The MPs showed a biphasic release pattern up to 72h. The Anderson cascade impactor (ACI) investigation demonstrated the highest drug deposition at stage 4, which revealed that the MPs can reach the lungs' secondary and terminal bronchi. Inhalable MPs had an efficient aerodynamic property with a mass median aerodynamic diameter (MMAD) of 2.63 ± 1.3 μm, a geometric standard deviation (GSD) of 1.93 ± 0.2 μm, and a fine particle fraction (FPF) of 87 ± 2.5%. Finally, in cytotoxicity studies on A549 cancer cells, MPs had an IC50 value of 0.6011 ± 0.8 μM, which was 85.68% lower than free drug. These findings suggest SRT-loaded inhalable PCL-based MPs as a novel NSCLC treatment.

Cyclosporine A-loaded chitosan extra-fine particles for deep pulmonary drug delivery: In vitro and in vivo evaluation

In this study, the extra-fine dry powder inhalers (DPIs) with chitosan (CS) as carrier were successfully prepared by ionic gel method combined with spray drying technique for deep pulmonary drug delivery of Cyclosporine A (CsA), using sodium hyaluronate (SHA) and sodium polyglutamate (SPGA) as polyanions. The CsA-loaded DPIs of CS-SHA-CsA and CS-SPGA-CsA were spherical particles with wrinkles on the surface, which were more conducive to improving the aerosol properties. The aerodynamic evaluation of CS-SHA-CsA and CS-SPGA-CsA showed that the fine particle fraction (FPF) reached up to 79.22 ± 2.12% and 81.55 ± 0.43%, while the emitted fraction (EF) reached 77.15 ± 1.46% and 78.29 ± 2.10%. In addition, the mass median aerodynamic diameter (MMAD) was calculated as 1.58 ± 0.04 μm and 1.94 ± 0.02 μm for CS-SHA-CsA and CS-SPGA-CsA, indicating that they were all extra-fine particles (d < 2 μm). These in vitro aerodynamic results showed that CS-SHA-CsA and CS-SPGA-CsA could reach the smaller airways, further improving therapeutic efficiency. The cell viability on A549 cell line results showed that CS-SHA-CsA and CS-SPGA-CsA were safe to deliver CsA to lungs. The in vivo pharmacokinetics consequence proved that inhalation administration of CS-SHA-CsA and CS-SPGA-CsA could significantly improve the bioavailability of CsA in vivo compared with oral administration of Neoral®, effectively reducing the risk of a series of adverse effects caused by systemic overexposure. In addition, the safety and compatibility of DPIs using SHA, SPGA, and CS as carriers for pulmonary drug delivery was verified by in vivo repeated dose inhalation toxicity. From these findings, the extra-fine DPIs with CS as carrier could be a viable delivery option for the deep pulmonary drug delivery of CsA relative to orally administered drug.

Integrated continuous manufacturing of inhalable remdesivir nanoagglomerate dry powders: Design, optimization and therapeutic potential for respiratory viral infections

While inhalable nanoparticle-based dry powders have demonstrated promising potential as next-generation respiratory medicines, erratic particle redispersibility and poor manufacturing reproducibility remain major hurdles hindering their translation from bench to bedside. We developed a one-step continuous process for fabricating inhalable remdesivir (RDV) nanoagglomerate dry powder formulations by integrating flash nanoprecipitation and spray drying. The nanosuspension formulation was optimized using a three-factor Box-Behnken design with a z-average particle size of 233.3 ± 2.3 nm and < 20% size change within six hours. The optimized inhalable nanoagglomerate dry powder formulation produced by spray drying showed adequate aqueous redispersibility (Sf/Si = 1.20 ± 0.01) and in vitro aerosol performance (mass median aerodynamic diameter of 3.80 ± 0.58 µm and fine particle fraction of 39.85 ± 10.16%). In A549 cells, RDV nanoparticles redispersed from the inhalable nanoagglomerate powders displayed enhanced and accelerated RDV cell uptake and negligible cytotoxicity at therapeutic RDV concentrations. No statistically significant differences were observed in the critical quality attributes of the inhalable nanoagglomerate powders produced from the continuous manufacturing and standalone batch modes. This work demonstrates the feasibility of large-scale continuous manufacturing of inhalable nanoagglomerate dry powder formulations, which pave the way for their clinical translation.

Role of Particle Size in Translational Research of Nanomedicines for Successful Drug Delivery: Discrepancies and Inadequacies

Despite significant research progress in substantiating the therapeutic merits of nanomedicines and the emergence of sophisticated nanotechnologies, the translation of this knowledge into new therapeutic modalities has been sluggish, indicating the need for a more comprehensive understanding of how the unique physicochemical properties of nanoparticles affect their clinical applications. Particle size is a critical quality attribute that impacts the bio-fate of nanoparticles, yet precise knowledge of its effect remains elusive with discrepancies among literature reports. This review aims to address this scientific knowledge gap from a drug development perspective by highlighting potential inadequacies during the evaluation of particle size effects. We begin with a discussion on the major issues in particle size characterization along with the corresponding remedies. The influence of confounding factors on biological effects of particle size, including colloidal stability, polydispersity, and in vitro drug release, are addressed for establishing stronger in vitro-in vivo correlation. Particle size design and tailoring approaches for successful nanoparticulate drug delivery beyond parenteral administration are also illustrated. We believe a holistic understanding of the effect of particle size on bio-fate, combined with consistent nanoparticle manufacturing platforms and tailored characterization techniques, would expedite the translation of nanomedicines into clinical practice.

Development of Large Hollow Particles for Pulmonary Delivery of Cyclosporine A

The purpose of this study was to prepare large hollow particles (LHPs) by spray drying for pulmonary delivery of cyclosporine A (CsA), using L-Leucine (LEU) and hydroxypropyl methylcellulose (HPMC) as excipients and ammonium bicarbonate (AB) as a porogen. The prepared LHPs were spherical particles composed of both CsA and LEU on the surface and HPMC on the inner layer. The formulation of CsA-LEU-0.8HPMC-AB as typical LHPs showed excellent in vitro aerodynamic performance with a minimum mass median aerodynamic diameter (MMAD) of 1.15 μm. The solubility of CsA-LEU-0.8HPMC-AB was about 5.5-fold higher than that of raw CsA, and the dissolution of CsA-LEU-0.8HPMC-AB suggested that the drug was released within 1 h. The cell viability of the A549 cell line showed that CsA-LEU-0.8HPMC-AB was safe for delivering CsA to the lungs. In addition, inhalation administration of CsA-LEU-0.8HPMC-AB with the Cmax and AUC0-∞ increasing by about 2-fold and 2.8-fold compared with the oral administration of Neoral® could achieve therapeutic drug concentrations with lower systemic exposure and significantly improve the in vivo bioavailability of CsA. From these findings, the LHPs, with the advantage of avoiding alveolar macrophage clearance, could be a viable choice for delivering CsA by inhalation administration relative to oral administration.

Doxorubicin-Loaded Platelet Decoys for Enhanced Chemoimmunotherapy Against Triple-Negative Breast Cancer in Mice Model

Introduction

Triple-negative breast cancer (TNBC) is a highly aggressive subtype with a poor prognosis. Current single-agent checkpoint therapy has limited effectiveness in TNBC patients. In this study, we developed doxorubicin-loaded platelet decoys (PD@Dox) for chemotherapy and induction of tumor immunogenic cell death (ICD). By combining PD-1 antibody, PD@Dox has the potential to enhance tumor therapy through chemoimmunotherapy in vivo.

Methods

Platelet decoys were prepared using 0.1% Triton X-100 and co-incubated with doxorubicin to obtain PD@Dox. Characterization of PDs and PD@Dox was performed using electron microscopy and flow cytometry. We evaluated the properties of PD@Dox to retain platelets through sodium dodecyl sulfate-polyacrylamide gel electrophoresis, flow cytometry, and thromboelastometry. In vitro experiments assessed drug-loading capacity, release kinetics, and the enhanced antitumor activity of PD@Dox. The mechanism of PD@Dox was investigated through cell viability assays, apoptosis assays, Western blot analysis, and immunofluorescence staining. In vivo studies were performed using a TNBC tumor-bearing mouse model to assess the anticancer effects.

Results

Electron microscopic observations confirmed that platelet decoys and PD@Dox exhibited a round shape similar to normal platelets. Platelet decoys demonstrated superior drug uptake and loading capacity compared to platelets. Importantly, PD@Dox retained the ability to recognize and bind tumor cells. The released doxorubicin induced ICD, resulting in the release of tumor antigens and damage-related molecular patterns that recruit dendritic cells and activate antitumor immunity. Notably, the combination of PD@Dox and immune checkpoint blockade therapy using PD-1 antibody achieved significant therapeutic efficacy by blocking tumor immune escape and promoting ICD-induced T cell activation.

Conclusion

Our results suggest that PD@Dox, in combination with immune checkpoint blockade therapy, holds promise as a potential strategy for TNBC treatment.

Quality by Design - Spray drying of Ciprofloxacin-Quercetin Fixed-Dose Combination Intended for Inhalation

Spray drying is a well-suited technique for producing fixed-dose drug combinations. There has been a growing interest in utilizing spray drying to engineer carrier-free inhalable drug particles. The aim of this study was to understand and optimise the spray drying process of a ciprofloxacin-quercetin fixed dose combination intended for pulmonary administration. A 2^4-1 fractional factorial design and multivariate data analysis was used to identify important process parameters and investigate correlations with particle characteristics. The independent variables were solute concentration along with the processing parameters: solution flow rate, atomizing air flow rate and inlet temperature. The dependent variables included particle size distribution, yield and residual moisture content (RMC). Correlations between dependent and independent variables were further investigated via principal component analysis. Overall, solution flow rate, atomizing air flow rate and inlet temperature were found to affect the particle size D_(v,50) and D_(v,90) while the solute concentration and the atomizing air flow rate mainly affected the span. The inlet temperature was the most important parameter affecting the RMC and the yield. The formulation with optimized independent variables had a D_(v,50) and span values of 2.42 µm and 1.81 with excellent process yield > 70% and low RMC i.e. 3.4%. The optimized formulation was further investigated for its in vitro aerosolization performance using next generation impactor (NGI); it exhibited high emitted dose (ED > 80%) and fine particle fractions (FPF > 70%) for both drugs.

Designing Aerosol Therapies Based on the Integrated Evaluation of In Vitro, In Vivo, and In Silico Data

Despite the advantages of the pulmonary route of administration and inhalable dosage forms, other routes of administration and dosage forms are often considered first to treat lung diseases. This occurs, in part, due to the perceived limitations of inhaled therapies resulting from the improper design and interpretation of their in vitro and in vivo evaluation. The present study outlines the elements that should be considered in the design, performance, and interpretation of the results of the preclinical evaluation of novel inhaled therapies. These elements are illustrated using an optimized model poly(lactic-co-glycolic) acid (PLGA) microparticle (MP) formulation to optimize the site of MPs deposition. The different expressions of MP size were determined, and their aerosol performance in devices used for animal (Microsprayer^® and Insufflator^®) and human studies (nebulizer and DPIs) was assessed using inertial impaction. Radiolabeled MPs were delivered to the lungs of rats by spray instillation to determine their site of deposition using single-photon emission computed tomography (SPECT) imaging. Recommendations to optimize the in vitro determinations are given, as well as suggestions to evaluate and interpret in vivo data in the context of the anatomy and physiology of the animal model and the corresponding in vitro data. Recommendations for the proper selection of in vitro parameters to inform in silico modeling are also given, as well as their integration with in vivo data.

Sustained-Release Powders Based on Polymer Particles for Pulmonary Delivery of Beclomethasone Dipropionate in the Treatment of Lung Inflammation

Inhaled corticosteroids are the mainstay in the management of lung inflammation associated to chronic lung diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Nonetheless, available inhalation products are mostly short-acting formulations that require frequent administrations and do not always produce the desired anti-inflammatory effects. In this work, the production of inhalable beclomethasone dipropionate (BDP) dry powders based on polymeric particles was attempted. As starting material, the PHEA-g-RhB-g-PLA-g-PEG copolymer was chosen, obtained by grafting 0.6, 2.4 and 3.0 mol%, respectively, of rhodamine (RhB), polylactic acid (PLA) and polyethylene glycol 5000 (PEG) on alpha,beta-poly(N-2-hydroxyethyl)DL-aspartamide (PHEA). The drug was loaded into the polymeric particles (MP) as an inclusion complex (CI) with hydroxypropyl-cyclodextrin (HP-β-Cyd) (at a stoichiometric ratio of 1:1) or as free form. The spray-drying (SD) process to produce MPs was optimized by keeping the polymer concentration (0.6 wt/vol%) constant in the liquid feed and by varying other parameters such as the drug concentration. The theoretical aerodynamic diameter (d_aer) values among the MPs are comparable and potentially suitable for inhalation, as confirmed also through evaluation of the experimental mass median aerodynamic diameter (MMAD_exp). BDP shows a controlled release profile from MPs that is significantly higher (more than tripled) than from Clenil^®. In vitro tests on bronchial epithelial cells (16HBE) and adenocarcinomic human alveolar basal epithelial cells (A549) showed that all the MP samples (empty or drug-loaded) were highly biocompatible. None of the systems used induced apoptosis or necrosis. Moreover, the BDP loaded into the particles (BDP-Micro and CI-Micro) was more efficient than free BDP to counteract the effects of cigarette smoke and LPS on release of IL-6 and IL-8.

Inhalable Nanoparticle-based Dry Powder Formulations for Respiratory Diseases: Challenges and Strategies for Translational Research

The emergence of novel respiratory infections (e.g., COVID-19) and expeditious development of nanoparticle-based COVID-19 vaccines have recently reignited considerable interest in designing inhalable nanoparticle-based drug delivery systems as next-generation respiratory therapeutics. Among various available devices in aerosol delivery, dry powder inhalers (DPIs) are preferable for delivery of nanoparticles due to their simplicity of use, high portability, and superior long-term stability. Despite research efforts devoted to developing inhaled nanoparticle-based DPI formulations, no such formulations have been approved to date, implying a research gap between bench and bedside. This review aims to address this gap by highlighting important yet often overlooked issues during pre-clinical development. We start with an overview and update on formulation and particle engineering strategies for fabricating inhalable nanoparticle-based dry powder formulations. An important but neglected aspect in in vitro characterization methodologies for linking the powder performance with their bio-fate is then discussed. Finally, the major challenges and strategies in their clinical translation are highlighted. We anticipate that focused research onto the existing knowledge gaps presented in this review would accelerate clinical applications of inhalable nanoparticle-based dry powders from a far-fetched fantasy to a reality.

Spray freeze dried niclosamide nanocrystals embedded dry powder for high dose pulmonary delivery

Based on the drug repositioning strategy, niclosamide (NCL) has shown potential applications for treating COVID-19. However, the development of new formulations for effective NCL delivery is still challenging. Herein, NCL-embedded dry powder for inhalation (NeDPI) was fabricated by a novel spray freeze drying technology. The addition of Tween-80 together with 1,2-Distearoyl-sn-glycero-3-phosphocholine showed the synergistic effects on improving both the dispersibility of primary NCL nanocrystals suspended in the feed liquid and the spherical structure integrity of the spray freeze dried (SFD) microparticle. The SFD microparticle size, morphology, crystal properties, flowability and aerosol performance were systematically investigated by regulating the feed liquid composition and freezing temperature. The addition of leucine as the aerosol enhancer promoted the microparticle sphericity with greatly improved flowability. The optimal sample (SF_{- 80}D-N₂₀L₂D₂T₁) showed the highest fine particle fraction of ∼47.83%, equivalently over 3.8 mg NCL that could reach the deep lung when inhaling 10 mg dry powders.