Inhaled bosentan microparticles for the treatment of monocrotaline-induced pulmonary arterial hypertension in rats

Excipients for Novel Inhaled Dosage Forms: An Overview

Pulmonary drug delivery is a form of local targeting to the lungs in patients with respiratory disorders like cystic fibrosis, pulmonary arterial hypertension (PAH), asthma, chronic pulmonary infections, and lung cancer. In addition, noninvasive pulmonary delivery also presents an attractive alternative to systemically administered therapeutics, not only for localized respiratory disorders but also for systemic absorption. Pulmonary delivery offers the advantages of a relatively low dose, low incidence of systemic side effects, and rapid onset of action for some drugs compared to other systemic administration routes. While promising, inhaled delivery of therapeutics is often complex owing to factors encompassing mechanical barriers, chemical barriers, selection of inhalation device, and limited choice of dosage form excipients. There are very few excipients that are approved by the FDA for use in developing inhaled drug products. Depending upon the dosage form, and inhalation devices such as pMDIs, DPIs, and nebulizers, different excipients can be used to provide physical and chemical stability and to deliver the dose efficiently to the lungs. This review article focuses on discussing a variety of excipients that have been used in novel inhaled dosage forms as well as inhalation devices.

Recent Updates in Inhalable Drug Delivery System against Various Pulmonary Diseases: Challenges and Future Perspectives

In the current scenario, pulmonary disease has become a prime burden for morbidity and mortality alongside tremendous social and economic crises throughout the world. Numerous conventional drug delivery system and treatment approach targeting the respiratory region has been driven out. However, effective and accurate recovery has not been achieved yet. In this regard, nanotechnological- based inhalable drug delivery strategy including polymeric, lipidic, or metallic-based respirable microparticles plays an indispensable role in circumventing numerous challenges faced during traditional treatment. Excellent aerodynamic performance leads to enhanced lung targetability, reduced dosing frequency and hence systemic toxicities, as well as improved pharmaceutical attributes, and therefore pharmacokinetic profiles are interminable factors associated with nanotechnologicalbased inhalable delivery. In this review, we comprehensively explored recent advancements in nanotechnologically engineered inhalable formulations targeting each of the mentioned pulmonary diseases. Moreover, we systematically discussed possible respiratory or systemic toxicities about the indeterminate and undefined physicochemical characteristics of inhaled particles.

Customizable Resveratrol Spray-dried Micro-composites for Inhalation as a Promising Contender for Treatment of Idiopathic Pulmonary Fibrosis

The past decades have witnessed tremendous expansion in utilization of plant-derived medicines as resveratrol (RES) in treating several diseases like idiopathic pulmonary fibrosis (IPF). RES can exhibit its role in treating IPF via its outstanding antioxidant and anti-inflammatory activities. The goal of this work was to formulate RES-loaded spray-dried composite microparticles (SDCMs) suitable for pulmonary delivery via dry powder inhaler (DPI). They were prepared by spray drying of a previously prepared RES-loaded bovine serum albumin nanoparticles (BSA NPs) dispersion using different carriers. RES-loaded BSA NPs, prepared by the desolvation technique, acquired suitable particle size of 177.67±0.95 nm and entrapment efficiency of 98.7±0.35% with perfectly uniform size distribution and high stability. Considering the attributes of the pulmonary route, NPs were co-spray dried with compatible carriers viz. mannitol, dextran, trehalose, leucine, glycine, aspartic acid, and glutamic acid to fabricate SDCMs. All formulations showed suitable mass median aerodynamic diameter less than 5 µm; that is suitable for deep lung deposition. However, the best aerosolization behavior was attained from using leucine with fine particle fraction (FPF) of 75.74%, followed by glycine with FPF of 54.7%. Finally, a pharmacodynamic study was conducted on bleomycin-induced mice, and it strongly revealed the role of the optimized formulations in alleviating PF through suppressing the levels of hydroxyproline, tumor necrosis factor-α and matrix metalloproteinase-9 with obvious improvements in the treated lung histopathology. These findings indicate that in addition to leucine, the glycine amino acid, which is not commonly used yet, is very promising in the formulation of DPIs.

High energy ball milling vs. nano spray drying in the development of supersaturated systems loaded with bosentan

In this study, high energy ball milling and nano spray drying were used to prepare amorphous solid dispersions of bosentan in copovidone for the first time. In particular, the impact of this polymer on the bosentan amorphization kinetics was investigated. Copovidone was shown to facilitate the amorphization of bosentan upon ball milling. As a result, bosentan was dispersed in copovidone at the molecular level, forming amorphous solid dispersions, regardless of the ratio of the compounds. The similarity between the values of the adjustment parameter that describes the goodness of fit of the Gordon-Taylor equation to the experimental data (K = 1.16) and that theoretically calculated for an ideal mixture (K = 1.13) supported these findings. The kind of coprocessing method determined the powder microstructure and the release rate. The opportunity to prepare submicrometer-sized spherical particles using nano spray drying was an important advantage of this technology. Both coprocessing methods allowed the formation of long-lasting supersaturated bosentan solutions in the gastric environment with maximum concentrations reached ranging from four (11.20 μg/mL) to more than ten times higher (31.17 μg/mL) than those recorded when the drug was vitrified alone (2.76 μg/mL). Moreover, this supersaturation lasted for a period of time at least twice as long as that of the amorphous bosentan processed without copovidone (15 min vs. 30-60 min). Finally, these binary amorphous solid dispersions were XRD-amorphous for a year of storage under ambient conditions.

Development of spray-dried N-acetylcysteine dry powder for inhalation

N-acetylcysteine (NAC) has both antioxidant and immunomodulatory activities and has been used as adjuvant therapy in several viral infections. Recently, NAC attracted attention for its possible role in reducing the affinity of the spike protein receptor binding domain to angiotensin-converting enzyme (ACE2) receptors. Since only NAC solutions are available for inhalation, the purpose of the work was to develop a NAC dry powder for inhalation using mannitol or leucine as excipient. The powder was successfully produced using co-spray-drying with leucine. ATR-FTIR analyses evidenced spectral variations ascribed to the formation of specific interactions between NAC and leucine. This effect on the NAC environment was not evident for NAC-mannitol powders, but mannitol was in a different polymorphic form compared to the supplied material. Both the feedstock concentration and the leucine content have an impact on the powder aerodynamic features. In particular, to maximize the respirable fraction, it is preferable to produce the powder starting from a 0.5 % w/v feedstock solution using 33 to 50 % w/w leucine content. The NAC-leucine powder was stable for ten months maintaining NAC content of 50 % (w/w) and about 200 μg of NAC was able to deposit on a transwell insert, useful for future in vitro studies.

Inhaled deep eutectic solvent based-nanoemulsion of pirfenidone in idiopathic pulmonary fibrosis

Pirfenidone (PRF), the first FDA-approved drug to treat idiopathic pulmonary fibrosis (IPF) and formulated as an oral dosage form, has many side effects. To enhance the therapeutic effect, we discovered a high-load nanoemulsion using a novel deep eutectic solvent (DES) and developed an inhalation drug with improved bioavailability. The DES of PRF and N-acetylcysteine were discovered, and their physicochemical properties were evaluated in this study. The mechanism of DES formation was confirmed by FT-IR and ¹H NMR and suggested to involve hydrogen bonding. The DES nanoemulsion in which the nano-sized droplets were dispersed is optimized by mixing the DES and distilled water in a ratio. The in vivo pharmacokinetic study showed that the pulmonary route of administration is superior to that of the oral route, and the DES nanoemulsion is superior to that of the PRF solution in achieving better bioavailability and lung distribution. The therapeutic effect of PRF for IPF could be confirmed through in vivo pharmacodynamics studies, including lung function assessment, enzyme-linked immunosorbent assay, histology, and micro-computed tomography using the bleomycin-induced IPF rat model. In addition, the pulmonary route administration of PRF is advantageous in reducing the toxicity risk.

Co-Spray Dried Nafamostat Mesylate with Lecithin and Mannitol as Respirable Microparticles for Targeted Pulmonary Delivery: Pharmacokinetics and Lung Distribution in Rats

Coronavirus disease 2019 (COVID-19), caused by a new strain of coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is spreading rapidly worldwide. Nafamostat mesylate (NFM) suppresses transmembrane serine protease 2 and SARS-CoV-2 S protein-mediated fusion. In this study, pharmacokinetics and lung distribution of NFM, administered via intravenous and intratracheal routes, were determined using high performance liquid chromatography analysis of blood plasma, lung lumen using bronchoalveolar lavage fluid, and lung tissue. Intratracheal administration had higher drug delivery and longer residual time in the lung lumen and tissue, which are the main sites of action, than intravenous administration. We confirmed the effect of lecithin as a stabilizer through an ex vivo stability test. Lecithin acts as an inhibitor of carboxylesterase and delays NFM decomposition. We prepared inhalable microparticles with NFM, lecithin, and mannitol via the co-spray method. The formulation prepared using an NFM:lecithin:mannitol ratio of 1:1:100 had a small particle size and excellent aerodynamic performance. Spray dried microparticles containing NFM, lecithin, and mannitol (1:1:100) had the longest residual time in the lung tissue. In conclusion, NFM-inhalable microparticles were prepared and confirmed to be delivered into the respiratory tract, such as lung lumen and lung tissue, through in vitro and in vivo evaluations.

Preparation and In Vivo Evaluation of a Lidocaine Self-Nanoemulsifying Ointment with Glycerol Monostearate for Local Delivery

Lidocaine, a commonly used local anesthetic, has recently been developed into a number of ointment products to treat hemorrhoids. This study examined its efficient delivery to the dermis through the pharmaceutical improvement of hemorrhoid treatment ointments. We attempted to increase the amount of skin deposition of lidocaine by forming a nanoemulsion through the self-nanoemulsifying effect that occurs when glycerol monostearate (GMS) is saturated with water. Using Raman mapping, the depth of penetration of lidocaine was visualized and confirmed, and the local anesthetic effect was evaluated via an in vivo tail-flick test. Evaluation of the physicochemical properties confirmed that lidocaine was amorphous and evenly dispersed in the ointment. The in vitro dissolution test confirmed that the nanoemulsifying effect of GMS accelerated the release of the drug from the ointment. At a specific concentration of GMS, lidocaine penetrated deeper into the dermis; the in vitro permeation test showed similar results. When compared with reference product A in the tail-flick test, the L5 and L6 compounds containing GMS had a significantly higher anesthetic effect. Altogether, the self-nanoemulsifying effect of GMS accelerated the release of lidocaine from the ointment. The compound with 5% GMS, the lowest concentration that saturated the dermis, was deemed most appropriate.