Ciprofloxacin-Loaded Inorganic-Organic Composite Microparticles To Treat Bacterial Lung Infection

Visual detection of ciprofloxacin using a multi-emission ratiometric fluorescence sensor based on the molecularly imprinted polymers doped with terbium(III) ions

Ciprofloxacin (CIP) is a commonly used antibiotic, but its abuse may cause bacterial resistance, posing a high risk to the environment and human health. Herein, based on the molecular imprinting technology, this study proposed a ratiometric fluorescence sensor employing the "post-doping" strategy, which aims to be rapid, selective, and visually easy-to-use for CIP detection to address antibiotic residues and environmental risks. Specifically, by exploiting the "antenna effect" of lanthanide metal ions (Ln3+), terbium (III) (Tb3+) chosen as a fluorescence-assisted functional monomer as well as the red emitting CdTe quantum dots (QDs) as the internal reference signal were introduced into multi-emission Tb3+-CdTe@SiO2@MIPs (TbMIPs). With the increase of CIP concentration, the variations among the fluorescence peaks within a multi-emission ratiometric fluorescence sensor not only induce a broader range of color changes, but also produce a more sensitive and stable effect through self-internal standard correction. The sensor showed a good trend in a wide concentration range within 0.08-50 μM and provided a satisfactory detection limit of 0.018 μM, which had lower detection limit for CIP than most of methods. It had demonstrated exceptional selectivity and had been successfully used to efficiently detect CIP in real samples including seawater, river water, milk and urine. Furthermore, when integrated with smartphone-based data processing capabilities, this sensor enabled highly sensitive visual detection under the 365 nm UV lamp device. Through innovative development, the wide color transition observed with the sensor makes it highly suitable for practical applications, enhancing its usability for further real-time monitoring.

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.

PK-PD Evaluation of Inhaled Microparticles loaded with Ciprofloxacin-Copper complex in a Rat Model of Chronic Pseudomonas aeruginosa Lung Infection

The potential gain in efficacy of pulmonary administration over IV administration of some antibiotics such as ciprofloxacin (CIP) may be limited by the short residence time of the drug at the site of infection after nebulization. Complexation of CIP with copper reduced its apparent permeability in vitro through a Calu-3 cell monolayer and greatly increased its pulmonary residence time after aerosolisation in healthy rats. Chronic P. aeruginosa lung infections in cystic fibrosis patients result in airway and alveolar inflammation that may increase the permeability of inhaled antibiotics and alter their fate in the lung after inhalation compared to what was seen in healthy conditions. The objective of this study was to compare the pharmacokinetics and efficacy of CIP-Cu²⁺ complex-loaded microparticles administered by pulmonary route with a CIP solution administered by IV to model rats with chronic lung infection. After a single pulmonary administration of microparticles loaded with CIP-Cu²⁺ complex, pulmonary exposure to CIP was increased 2077-fold compared to IV administration of CIP solution. This single lung administration significantly reduced the lung burden of P. aeruginosa expressed as CFU/lung measured 24 h after administration by 10-fold while IV administration of the same dose of CIP was ineffective compared to the untreated control. This better efficacy of inhaled microparticles loaded with CIP-Cu²⁺ complex compared with CIP solution can be attributed to the higher pulmonary exposure to CIP obtained with inhaled CIP-Cu²⁺ complex-loaded microparticles than that obtained with IV solution.

Recent Advances in Pharmaceutical Approaches of Antimicrobial Agents for Selective Delivery in Various Administration Routes

Globally, the increase of pathogenic bacteria with antibiotic-resistant characteristics has become a critical challenge in medical treatment. The misuse of conventional antibiotics to treat an infectious disease often results in increased resistance and a scarcity of effective antimicrobials to be used in the future against the organisms. Here, we discuss the rise of antimicrobial resistance (AMR) and the need to combat it through the discovery of new synthetic or naturally occurring antibacterial compounds, as well as insights into the application of various drug delivery approaches delivered via various routes compared to conventional delivery systems. AMR-related infectious diseases are also discussed, as is the efficiency of various delivery systems. Future considerations in developing highly effective antimicrobial delivery devices to address antibiotic resistance are also presented here, especially on the smart delivery system of antibiotics.

Targeting lung macrophages for fungal and parasitic pulmonary infections with innovative amphotericin B dry powder inhalers

The incidence of fungal pulmonary infections is known to be on the increase, and yet there is an alarming gap in terms of marketed antifungal therapies that are available for pulmonary administration. Amphotericin B (AmB) is a highly efficient broad-spectrum antifungal only marketed as an intravenous formulation. Based on the lack of effective antifungal and antiparasitic pulmonary treatments, the aim of this study was to develop a carbohydrate-based AmB dry powder inhaler (DPI) formulation, prepared by spray drying. Amorphous AmB microparticles were developed by combining 39.7 % AmB with 39.7 % γ-cyclodextrin, 8.1 % mannose and 12.5 % leucine. An increase in the mannose concentration from 8.1 to 29.8 %, led to partial drug crystallisation. Both formulations showed good in vitro lung deposition characteristics (80 % FPF < 5 µm and MMAD < 3 µm) at different air flow rates (60 and 30 L/min) when used with a DPI, but also during nebulisation upon reconstitution in water.

Inhaled ciprofloxacin-loaded poly(2-ethyl-2-oxazoline) nanoparticles from dry powder inhaler formulation for the potential treatment of lower respiratory tract infections

Lower respiratory tract infections (LRTIs) are one of the fatal diseases of the lungs that have severe impacts on public health and the global economy. The currently available antibiotics administered orally for the treatment of LRTIs need high doses with frequent administration and cause dose-related adverse effects. To overcome this problem, we investigated the development of ciprofloxacin (CIP) loaded poly(2-ethyl-2-oxazoline) (PEtOx) nanoparticles (NPs) for potential pulmonary delivery from dry powder inhaler (DPI) formulations against LRTIs. NPs were prepared using a straightforward co-assembly reaction carried out by the intermolecular hydrogen bonding among PEtOx, tannic acid (TA), and CIP. The prepared NPs were characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction analysis (PXRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The CIP was determined by validated HPLC and UV spectrophotometry methods. The CIP loading into the PEtOx was between 21-67% and increased loading was observed with the increasing concentration of CIP. The NP sizes of PEtOx with or without drug loading were between 196-350 nm and increased with increasing drug loading. The in vitro CIP release showed the maximum cumulative release of about 78% in 168 h with a burst release of 50% in the first 12 h. The kinetics of CIP release from NPs followed non-Fickian or anomalous transport thus suggesting the drug release was regulated by both diffusion and polymer degradation. The in vitro aerosolization study carried out using a Twin Stage Impinger (TSI) at 60 L/min air flow showed the fine particle fraction (FPF) between 34.4% and 40.8%. The FPF was increased with increased drug loading. The outcome of this study revealed the potential of the polymer PEtOx as a carrier for developing CIP-loaded PEtOx NPs as DPI formulation for pulmonary delivery against LRTIs.

Developing ciprofloxacin dry powder for inhalation: A story of challenges and rational design in the treatment of cystic fibrosis lung infection

Cystic fibrosis (CF) is an inherited multisystem disease affecting the lung which leads to a progressive decline in lung function as a result of malfunctioning mucociliary clearance and subsequent chronic bacterial infections. Pseudomonas aeruginosa is the predominant cause of lung infection in CF patients and is associated with significant morbidity and mortality. Thus, antibiotic therapy remains the cornerstone of the treatment of CF. Pulmonary delivery of antibiotics for lung infections significantly reduces the required dose and the associated systemic side effects while improving therapeutic outcomes. Ciprofloxacin is one of the most widely used antibiotics against P. aeruginosa and the most effective fluoroquinolone. However, in spite of the substantial amount of research aimed at developing ciprofloxacin powder for inhalation, none of these formulations has been commercialized. Here, we present an integrated view of the diverse challenges associated with delivering ciprofloxacin dry particles to the lungs of CF patients and the rationales behind recent formulations of ciprofloxacin dry powder for inhalation. This review will discuss the challenges in developing ciprofloxacin powder for inhalation along with the physiological and pathophysiological challenges such as ciprofloxacin lung permeability, overproduction of viscous mucus and bacterial biofilms. The review will also discuss the current and emerging particle engineering approaches to overcoming these challenges. By doing so, we believe the review will help the reader to understand the current limitations in developing an inhalable ciprofloxacin powder and explore new opportunities of rational design strategies.

Pulmonary Drug Delivery of Antimicrobials and Anticancer Drugs Using Solid Dispersions

It is well established that currently available inhaled drug formulations are associated with extremely low lung deposition. Currently available technologies alleviate this low deposition problem via mixing the drug with inert larger particles, such as lactose monohydrate. Those inert particles are retained in the inhalation device or impacted in the throat and swallowed, allowing the smaller drug particles to continue their journey towards the lungs. While this seems like a practical approach, in some formulations, the ratio between the carrier to drug particles can be as much as 30 to 1. This limitation becomes more critical when treating lung conditions that inherently require large doses of the drug, such as antibiotics and antivirals that treat lung infections and anticancer drugs. The focus of this review article is to review the recent advancements in carrier free technologies that are based on coamorphous solid dispersions and cocrystals that can improve flow properties, and help with delivering larger doses of the drug to the lungs.

In vivo efficacy of a dry powder formulation of ciprofloxacin-copper complex in a chronic lung infection model of bioluminescent Pseudomonas aeruginosa

A significant limitation of locally delivered treatments for chronic pulmonary infections is often the short residence time within the airways. Ciprofloxacin (CIP), for example, undergoes rapid absorption from the airway lumen. Previously, we demonstrated that the complexation of CIP with copper (CIP-Cu) reduces its apparent epithelial permeability and pulmonary absorption rate without affecting antimicrobial activity against Pseudomonas aeruginosa grown planktonically or as biofilms. This study aimed to evaluate the in vivo efficacy of CIP-Cu, prepared as a dry powder, in a chronic lung infection model. The powders were prepared by jet milling (CIP-HCl) and by spray drying (CIP-Cu). A bioluminescent strain of P. aeruginosa (PAO1::p16Slux) was used to prepare bacteria-loaded agar beads that were inoculated intratracheally to rats. The dynamics of the infection were monitored using luminometry. The bacteria/beads ratio was optimized to allow the highest luminescence signal and animal survival for 8 days. The efficacy of the treatment was evaluated by luminometry in addition to the end-point (Day 8) where colony counting was performed after lung harvesting. Luminescent P. aeruginosa entrapped in agar beads were useful to monitor the spatial development of the chronic lung infection in rats. The rats were treated with the dry powders in a nose-only inhalation exposure system (NOIES). CIP-Cu and CIP-HCl powders showed similar aerodynamic properties and comparable CIP lung deposition. However, treatment with CIP-Cu significantly (p < 0.01) reduced by 4-log the number of CFU of P. aeruginosa per lung in the chronic infection model, whereas CIP-HCl effect was not different from the untreated control group.

Control of the Lung Residence Time of Highly Permeable Molecules after Nebulization: Example of the Fluoroquinolones

Pulmonary drug delivery is a promising strategy to treat lung infectious disease as it allows for a high local drug concentration and low systemic side effects. This is particularly true for low-permeability drugs, such as tobramycin or colistin, that penetrate the lung at a low rate after systemic administration and greatly benefit from lung administration in terms of the local drug concentration. However, for relatively high-permeable drugs, such as fluoroquinolones (FQs), the rate of absorption is so high that the pulmonary administration has no therapeutic advantage compared to systemic or oral administration. Formulation strategies have thus been developed to decrease the absorption rate and increase FQs’ residence time in the lung after inhalation. In the present review, some of these strategies, which generally consist of either decreasing the lung epithelium permeability or decreasing the release rate of FQs into the epithelial lining fluid after lung deposition, are presented in regards to their clinical aspects.

Efficacy of Ciprofloxacin and Its Copper Complex against Pseudomonas aeruginosa Biofilms

A limitation of antibiotic treatments for P. aeruginosa (PA) chronic pulmonary infections is the reduced efficacy due to sub-therapeutic concentrations at the infection site and the development of biofilm. A novel approach to sustain ciprofloxacin (CIP) in the lungs after inhalation is to reduce its pulmonary absorption rate by its complexation with copper (CIP-Cu). This study aimed to evaluate the antimicrobial action of cationic CIP-Cu complex in PA biofilms in terms of drug concentration and time. Two PA strains, PA01 and PA14, were grown to form biofilm layers in equilibrium with planktonic cells. Static parameters such as pyoverdine production by planktonic cells, enzymatic activity within biofilms, and biofilm biomass 24 h after the addition of CIP or CIP-Cu were evaluated. Also, the kinetic effects of CIP and CIP-Cu on biofilms were evaluated by bioluminescence kinetics using transgenic strains. No differences were observed between CIP and CIP-Cu in terms of efficacy against biofilms, validating the potential of using this complex to treat PA biofilms. Interestingly, CIP concentrations slightly below the MIC value against planktonic bacteria stimulated both virulence and biofilm PA01 production. These results support the need to accurately achieve high CIP concentration in the lungs, which can be more easily achieved by pulmonary delivery of advanced CIP formulations (CIP-metal complexes or liposomal CIP) instead of the oral administration of free CIP.

Use of leucine to improve aerodynamic properties of ciprofloxacin-loaded maltose microparticles for inhalation

Ciprofloxacin (CIP) apparent permeability and absorption rate across the pulmonary epithelium can be controlled by its complexation with copper (II) ion. The aim of the current study was to formulate CIP-Cu-loaded microparticles comprising three main excipients, calcium carbonate, maltose and L-leucine, and to process by spray drying so as to generate particles with suitable aerodynamic properties for pulmonary delivery using a dry powder inhaler. Different maltose:calcium carbonate ratios were used to prepare microparticles, and the role of the excipients on the particles’ physicochemical properties, stability, and aerosolization characteristics were investigated. All the formulations without L-leucine were fully X-ray amorphous. In the presence of L-leucine, diffraction peaks of low intensity were observed, which were attributed to the crystallization of the L-leucine at the particle surfaces. The addition of L-leucine modified the particle morphology and reduced the median geometric and aerodynamic diameters to 3.2 and 3.4 µm, respectively. The fine particle fraction of powder emitted from a Handihaler® device was increased up to 65.4%, predicting high total lung deposition. Stability studies showed that the powder X-ray diffraction pattern did not change over 21 months of storage in desiccated conditions, suggesting a good physical stability of the optimized formulation comprised of CIP-Cu, maltose and L-Leucine.

Fluorescent molecularly imprinted nanoparticles for selective and rapid detection of ciprofloxacin in aquaculture water

Fluorescent molecularly imprinted nanoparticles have shown great promise in the field of chemical analysis or detection because of their high stability, selectivity, and sensitivity. In this work, fluorescent molecularly imprinted nanoparticles were synthesized by precipitation polymerization employing fluorescein isothiocyanate as luminescent material, which could efficiently and rapidly detect ciprofloxacin in water samples. The prepared fluorescent molecularly imprinted nanoparticles had remarkable stability and good selectivity with the method detection limit low to 4.04 nm. In addition, the fluorescent-imprinted nanoparticles were capable of identifying the target with high detection efficiency and were applied to the detection of ciprofloxacin in aquaculture water with complex composition. All these would provide the direct monitoring of ciprofloxacin in environmental water with a promising fluorescent imprinting strategy.

Development of ciprofloxacin-loaded poly(vinyl alcohol) dry powder formulations for lung delivery

Polymeric microparticles are micro carriers for the sustained drug delivery of drugs in the lungs, used as alternatives to the use of established excipients. This study aims to develop and characterize inhalable ciprofloxacin (CPx)-loaded poly(vinyl alcohol) (PVA) microparticles by a single-step spray-drying procedure. The optimization of the processing parameters was achieved by an orthogonal design of the most relevant processing parameters (polymer concentration, feed rate and inlet temperature). The obtained spray-dried particles showed a drug encapsulation efficiency higher than 90%. Furthermore, PVA-CPx formulations, with drug contents up to 10 wt%, showed a morphology and size suitable for inhalation, with a sustained release profile over 24 h. Data from Fourier transformed infra-red spectroscopy and differential scanning calorimetry indicated absence of interaction between the polymer matrix and the drug. Aerodynamic assessment of PVA-CPx 10 wt% was determined by the next generation impactor (NGI), using spray-dried CPx as a control. The results showed improved values of mass median aerodynamic diameter (5.06±0.10μm) and a fine particle fraction (39.78±0.98%) when comparing with the CPx alone (5.33±0.39μm and 30.43±1.38%). This study highlights the potential of spray-dried PVA microparticles as drug carriers for lung local delivery of antibiotics.

Antimicrobial gelatin-based elastomer nanocomposite membrane loaded with ciprofloxacin and polymyxin B sulfate in halloysite nanotubes for wound dressing

Bacterial infection is a major problem world-wide, especially in wound treatment where it can severely prolong the healing process. In this study, a double drug co-delivery elastic antibacterial nanocomposite was developed by combining ciprofloxacin (CPX) and polymyxin B sulfate-loaded halloysite clay nanotubes (HNTs-B) into a gelatin elastomer. CPX nanoparticles which act against both gram positive and gram-negative bacterium were dispersed directly in the matrix, and polymyxin B sulfate was loaded in HNTs and then distributed into the matrix. The effect of CPX and HNTs-B content on the physical properties, cytotoxicity, fibroblast adhesion and proliferation, in vitro drug release behavior and anti-bacterial properties were systematically investigated. The ciprofloxacin crystals and HNT-B were distributed in the matrix uniformly. The HNTs in the drug loading system not only enhanced the matrix' tensile strength but also slowed down the release rate of the high dissoluble polymyxin B sulfate. When the amount of HNT in the matrix increased, the thermal stability and tensile strength also increased but the polymyxin B sulfate release rate decreased because the HNTs prevented the drug release inside. All the nanocomposites exhibited antimicrobial activity against both gram-negative and gram-positive bacteria with the dual combination of drugs released from the nanocomposites. Furthermore, this kind of gelatin-based nanocomposites possesses higher water-absorbing quality, low cytotoxicity, adaptable biodegradability and good elasticity which can satisfy the requirements for an ideal biomaterial for use in wound healing applications.

Antimicrobial molecules in the lung: formulation challenges and future directions for innovation

Inhaled antimicrobials have been extremely beneficial in treating respiratory infections, particularly chronic infections in a lung with cystic fibrosis. The pulmonary delivery of antibiotics has been demonstrated to improve treatment efficacy, reduce systemic side effects and, critically, reduce drug exposure to commensal bacteria compared with systemic administration, reducing selective pressure for antimicrobial resistance. This review will explore the specific challenges of pulmonary delivery of a number of differing antimicrobial molecules, and the formulation and technological approaches that have been used to overcome these difficulties. It will also explore the future challenges being faced in the development of inhaled products and respiratory infection treatment, and identify future directions of innovation, with a particular focus on respiratory infections caused by multiple drug-resistant pathogens.

New aerosol formulation to control ciprofloxacin pulmonary concentration

Ciprofloxacin (CIP) apparent permeability across a pulmonary epithelium model can be controlled by the affinity of its complex with a metal cation. The higher the complex affinity, the larger is the reduction in CIP apparent permeability. The aim of this study was to evaluate if the control of the CIP apparent permeability observed in vitro could be transposed in vivo to control the CIP lung-to-blood absorption rate and CIP concentrations in the lung epithelial lining fluid (ELF) after intratracheal (IT) administration. Two types of innovative inhalable microparticles loaded with the low-affinity CIP-calcium complex (CIP-Ca) or with the high-affinity CIP-copper complex (CIP-Cu) were formulated and characterized. Then, ELF and plasma pharmacokinetics of CIP were studied in rats after IT administration of these two types of microparticles and of a CIP solution (2.5mg/kg). The presence of Cu²⁺ had little effect on the microparticle properties and the dry powder had aerodynamic properties which allowed it to reach the lungs. CIP concentrations in ELF were much higher after CIP-Cu microparticles IT administration compared to the other two formulations, with mean AUC_ELF to AUC_u,plasma ratios equal to 1069, 203 and 9.8 after CIP-Cu microparticles, CIP-Ca microparticles and CIP solution pulmonary administration, respectively. No significant modification of lung toxicity markers was found (lactate dehydrogenase and total protein). CIP complexation with Cu²⁺ seems to be an interesting approach to obtain high CIP concentrations in the ELF of lungs after dry powder IT administration.

Nebulised antibiotherapy: conventional versus nanotechnology-based approaches, is targeting at a nano scale a difficult subject?

Nebulised antibiotics offer great advantages over intravenously administered antibiotics and other conventional antibiotic formulations. However, their use is not widely standardized in the current clinical practice. This is the consequence of large variability in the performance of nebulisers, patient compliance and a deficiency of robust preclinical and clinical data. Nebulised antibiotherapy may play a significant role in future pulmonary drug delivery treatments as it offers the potential to achieve both a high local drug concentration and a lower systemic toxicity. In this review, the physicochemical parameters required for optimal deposition to the lung in addition to the main characteristics of currently available formulations and nebuliser types are discussed. Particular attention will be focused on emerging nanotechnology based approaches which are revolutionizing inhaled therapies used to treat both infections and lung cancer. Promising carriers such as Trojan-Horse microparticles, liposomes, polymeric and lipid nanoparticulate systems have been investigated and proposed as viable options. In order to achieve site-specific targeting and to optimize the PK/PD balance critical nanoscale design parameters such as particle size, morphology, composition, rigidity and surface chemistry architecture must be controlled. Development of novel excipients to manufacture these nanomedicines and assessment of their toxicity is also a keystone and will be discussed in this review.

Cellular internalization and transport of biodegradable polyester dendrimers on a model of the pulmonary epithelium and their formulation in pressurized metered-dose inhalers

The purpose of this study was to evaluate the effect of generation and surface PEGylation of degradable polyester-based dendrimers nanocarriers on their interactions with an in vitro model of the pulmonary epithelium as well as to assess the ability to formulate such carriers in propellant-based, portable oral-inhalation devices to determine their potential for local and systemic delivery of drugs to and through the lungs. Hydroxyl (-OH) terminated polyester dendrimers of generation 3 and 4 (G3, and G4) were synthesized using a divergent approach. G4 was surface-modified with PEG (1,000Da). All dendrimers and their building blocks were determined to be highly compatible with the model pulmonary epithelium, with toxicity profiles much more favorable than non-degradable polyamidoamine dendrimers (PAMAM). The transport of the species from the apical to basolateral side across polarized Calu-3 monolayers showed to be generation and surface-chemistry (PEGylation) dependent. The extent of the transport is modulated by their interaction with the polarized epithelium and their transient opening of the tight junctions. G3 was the one most efficiently internalized by the epithelium, and had a small impact on the integrity of the monolayer. On the other hand, the PEGylated G4 was the one least internalized by the polarized epithelium, and at the same time had a more pronounced transient impact on the cellular junctions, resulting in more efficient transport across the cell monolayer. PEGylation of the dendrimer surface played other roles as well. PEGylation modulated the degradation profile of the dendrimer, slowing the process in a step-wise fashion - first the PEG layer is shed and then the dendrimer starts degrading. PEGylation also helped increase the solvation of the nanocarriers by the hydrofluoroalkane propellant used in pressurized metered-dose inhalers, resulting in formulations with excellent dispersibility and aerosol quality (deep lung deposition of 88.5%), despite their very small geometric diameter. The combined in vitro and formulation performance results shown here demonstrated that degradable, modified polyester dendrimers may serve as a valuable platform that can be tailored to target the lung tissue for treating local diseases, or the circulation, using the lungs as pathway to the bloodstream.