Mediating bio-fate of polymeric cholecalciferol nanoparticles through rational size control

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.

Intracerebral fate of organic and inorganic nanoparticles is dependent on microglial extracellular vesicle function

Nanoparticles (NPs) represent an important advance for delivering diagnostic and therapeutic agents across the blood-brain barrier. However, NP clearance is critical for safety and therapeutic applicability. Here we report on a study of the clearance of model organic and inorganic NPs from the brain. We find that microglial extracellular vesicles (EVs) play a crucial role in the clearance of inorganic and organic NPs from the brain. Inorganic NPs, unlike organic NPs, perturb the biogenesis of microglial EVs through the inhibition of ERK1/2 signalling. This increases the accumulation of inorganic NPs in microglia, hindering their elimination via the paravascular route. We also demonstrate that stimulating the release of microglial EVs by an ERK1/2 activator increased the paravascular glymphatic pathway-mediated brain clearance of inorganic NPs. These findings highlight the modulatory role of microglial EVs on the distinct patterns of the clearance of organic and inorganic NPs from the brain and provide a strategy for modulating the intracerebral fate of NPs.

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.

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.