Development and characterization of a spray-dried inhalable ternary combination for the treatment of Pseudomonas aeruginosa biofilm infection in cystic fibrosis

Cystic fibrosis (CF) is an inherited lung disease characterised by the accumulation of thick layers of dried mucus in the lungs which serve as a nidus for chronic infection. Pseudomonas aeruginosa is the predominant cause of chronic lung infection in cystic fibrosis. The dense mucus coupled with biofilm formation hinder antibiotic penetration and prevent them from reaching their target. Mucoactive agents are recommended in the treatment of CF in combination with antibiotics. In spite of the extensive research in developing novel drug combinations for the treatment of lung infection in CF, to our knowledge, there is no study that combines antibiotic, antibiofilm and mucoactive agent in a single inhaled dry powder formulation. In the present study, we investigate the possibility of adding a mucoactive agent to our previously developed ciprofloxacinquercetin (antibiotic-antibiofilm) dry powder for inhalation. Three mucoactive agents, namely mannitol (MAN), N-acetyl-L-cysteine (NAC) and ambroxol hydrochloride (AMB), were investigated for this purpose. The ternary combinations were prepared via spray drying without the addition of excipients. All ternary combinations conserved or improved the antibacterial and biofilm inhibition activities of ciprofloxacin against P. aeruginosa (ATCC 10145). The addition of AMB resulted in an amorphous ternary combination (SD-CQA) with superior physical stability as indicated by DSC and nonambient XRPD. Furthermore, SD-CQA displayed better in vitro aerosolization performance (ED ∼ 71 %; FPF ∼ 49 %) compared to formulations containing MAN and NAC (ED ∼ 64 % and 44 %; FPF ∼ 44 % and 29 %, respectively). In conclusion, a ternary drug combination powder with suitable aerosolization, physical stability and antibacterial/antibiofilm properties was prepared by a single spray drying step.

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.

Inhaled fixed-dose combination powders for the treatment of respiratory infections

INTRODUCTION

Respiratory infections are a major cause of morbidity and mortality. As an alternative to systemic drug administration, inhaled drug delivery can produce high drug concentrations in the lung tissue to overcome resistant bacteria. The development of inhaled fixed-dose combination powders (I-FDCs) is promising next step in this field, as it would enable simultaneous drug-drug or drug-adjuvant delivery at the site of infection, thereby promoting synergistic activity and improving patient compliance.

AREAS COVERED

This review covers the clinical and pharmaceutical rationales for the development of I-FDCs for the treatment of respiratory infections, relevant technologies for particle and powder generation, and obstacles which must be addressed to achieve regulatory approval.

EXPERT OPINION

I-FDCs have been widely successful in the treatment of asthma and chronic obstructive pulmonary disease; however, application of I-FDCs towards the treatment of respiratory infections carries additional challenges related to the high dose requirements and physicochemical characteristics of anti-infective drugs. At present, co-spray drying is an especially promising approach for the development of composite fixed-dose anti-infective particles for inhalation. Though the majority of fixed-dose research has thus far focused on the combination of multiple antibiotics, future work may shift to the additional inclusion of immunomodulatory agents or repurposed non-antibiotics.

Pulmonary route of administration is instrumental in developing therapeutic interventions against respiratory diseases

Pulmonary route of drug delivery has drawn significant attention due to the limitations associated with conventional routes and available treatment options. Drugs administered through pulmonary route has been an important research area that focuses on to developing effective therapeutic interventions for asthma, chronic obstructive pulmonary disease, tuberculosis, lung cancer etc. The intravenous route has been a natural route of delivery of proteins and peptides but associated with several issues including high cost, needle-phobia, pain, sterility issues etc. These issues might be addressed by the pulmonary administration of macromolecules to achieving an effective delivery and efficacious therapeutic impact. Efforts have been made to develop novel drug delivery systems (NDDS) such as nanoparticles, microparticles, liposomes and their engineered versions, polymerosomes, micelles etc to achieving targeted and sustained delivery of drug(s) through pulmonary route. Further, novel approaches such as polymer-drug conjugates, mucoadhesive particles and mucus penetrating particles have attracted significant attention due to their unique features for an effective delivery of drugs. Also, use of semi flourinated alkanes is in use for improvising the pulmonary delivery of lipophilic drugs. Present review focuses on to unravel the mechanism of pulmonary absorption of drugs for major pulmonary diseases. It summarizes the development of interventional approaches using various particulate and vesicular drug delivery systems. In essence, the orchestrated attempt presents an inflammatory narrative on the advancements in the field of pulmonary drug delivery.

Inhaled mucoactive particles with tailored architecture for enhanced aerodynamicity, stability and efficacy

In respiratory and genetic disorders such as asthma, chronic obstructive pulmonary disease (COPD), chronic bronchitis and cystic fibrosis (CF), the lungs produce excess mucus, resulting in a thickened mass, which clogs up the airways and reduces airflow. Consequently, breathing becomes more difficult. Medications that break down the structure of mucus will be especially useful in managing the early symptoms of these diseases and preventing their progression into the more severe forms. This work therefore seeks to develop an inhaled mucoactive dry powder formulation that is efficacious on multiple fronts. As an innovative step, sodium chloride was used to tailor the surface architecture of ambroxol hydrochloride particles, such that the resulting angular features on the surfaces contributed to the creation of corrugated particles with enhanced aerodynamicity. The optimized spray-dried powder particles were of respirable-size (d₅₀ of 2.85 ± 0.15 μm) and moderately corrugated. When the crystalline powder was dispersed via an Aerolizer® inhaler at 60 L/min, it gave a fine particle fraction (FPF) of ~31%, which was a ten-fold improvement over the unmodified species (i.e. ambroxol hydrochloride alone). Tests on artificial sputum medium (ASM) showed that the optimized formulation was potentially useful in liquefying the mucus, which favorably pointed towards the effectiveness of the formulation. In addition, the formulation was also stable to moisture ingress (up to ~60% RH) and had good flowability. Hence, the advent of angular adjuvant sodium chloride particles in a mucoactive formulation conferred a three-fold benefit to the product: (1) Improved aerodynamicity and flowability, (2) Enhanced moisture stability and (3) Synergistic mucolytic properties.

Inhaled Antibiotics for Gram-Negative Respiratory Infections

Gram-negative organisms comprise a large portion of the pathogens responsible for lower respiratory tract infections, especially those that are nosocomially acquired, and the rate of antibiotic resistance among these organisms continues to rise. Systemically administered antibiotics used to treat these infections often have poor penetration into the lung parenchyma and narrow therapeutic windows between efficacy and toxicity. The use of inhaled antibiotics allows for maximization of target site concentrations and optimization of pharmacokinetic/pharmacodynamic indices while minimizing systemic exposure and toxicity. This review is a comprehensive discussion of formulation and drug delivery aspects, in vitro and microbiological considerations, pharmacokinetics, and clinical outcomes with inhaled antibiotics as they apply to disease states other than cystic fibrosis. In reviewing the literature surrounding the use of inhaled antibiotics, we also highlight the complexities related to this route of administration and the shortcomings in the available evidence. The lack of novel anti-Gram-negative antibiotics in the developmental pipeline will encourage the innovative use of our existing agents, and the inhaled route is one that deserves to be further studied and adopted in the clinical arena.

Inhalable Clarithromycin Microparticles for Treatment of Respiratory Infections

PURPOSE

The aim of this work was to develop clarithromycin microparticles (CLARI-MP) and evaluate their aerodynamic behavior, safety in bronchial cells and anti-bacterial efficacy.

METHODS

Microparticles containing clarithromycin were prepared as dry powder carrier for inhalation, using leucine and chitosan. CLARI-MP were deposited on Calu-3 grown at air-interface condition, using the pharmaceutical aerosol deposition device on cell cultures (PADDOCC). Deposition efficacy, transport across the cells and cytotoxicity were determined. Anti-antibacterial effect was evaluated against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus.

RESULTS

Microparticles were of spherical shape, smooth surface and size of about 765 nm. Aerosolization performance showed a fine particle fraction (FPF) of 73.3%, and a mass median aerodynamic diameter (MMAD) of 1.8 μm. Deposition on Calu-3 cells using the PADDOCC showed that 8.7 μg/cm(2) of deposited powder were transported to the basolateral compartment after 24 h. The safety of this formulation is supported by the integrity of the cellular epithelial barrier and absence of toxicity, and the antimicrobial activity demonstrated for Gram positive and Gram negative bacteria.

CONCLUSIONS

The appropriate aerodynamic properties and the excellent deposition on Calu-3 cells indicate that clarithromycin microparticles are suitable for administration via pulmonary route and are efficient to inhibit bacteria proliferation.

Inhaled formulations and pulmonary drug delivery systems for respiratory infections

Respiratory infections represent a major global health problem. They are often treated by parenteral administrations of antimicrobials. Unfortunately, systemic therapies of high-dose antimicrobials can lead to severe adverse effects and this calls for a need to develop inhaled formulations that enable targeted drug delivery to the airways with minimal systemic drug exposure. Recent technological advances facilitate the development of inhaled anti-microbial therapies. The newer mesh nebulisers have achieved minimal drug residue, higher aerosolisation efficiencies and rapid administration compared to traditional jet nebulisers. Novel particle engineering and intelligent device design also make dry powder inhalers appealing for the delivery of high-dose antibiotics. In view of the fact that no new antibiotic entities against multi-drug resistant bacteria have come close to commercialisation, advanced formulation strategies are in high demand for combating respiratory 'super bugs'.