Dry Powder Formulation of Azithromycin for COVID-19 Therapeutics

Aim: The aim of this study is to develop dry powder formulations of azithromycin-loaded poly(lactic-co-glycolic acid) (PLGA) nanocomposite microparticles for pulmonary delivery to improve the low bioavailability of azithromycin. Methods: Double emulsion method was used to produce nanoparticles, which were then spray dried to form nanocomposite microparticles. Encapsulation efficiency and drug loading were analysed, and formulations were characterised by particle size, zeta potential, morphology, crystallinity and in-vitro aerosol dispersion performance. Results: The addition of chitosan changed the neutrally-charged azithromycin only formulation to positively-charged nanoparticles. However, the addition of chitosan also increased the particle size of the formulations. It was observed in the NGI® data that there is an improvement in dispersibility of the chitosan-related formulations. Conclusion: It was demonstrated in this study that all dry powder formulations were able to deliver azithromycin to the deep lung regions, which suggests the potential of using azithromycin via pulmonary drug delivery as an effective method to treat COVID-19.

Current Research on Spray-Dried Chitosan Nanocomposite Microparticles for Pulmonary Drug Delivery

Using the pulmonary route for systemic and local drug delivery is an attractive method of drug administration because it has a high alveolar surface area, abundant blood flow, a thin airblood barrier, and low metabolic activity. In recent years, the evolution of inhalable chitosan nanocomposite microparticles formulations enabled researchers to develop new pulmonary drug delivery platforms that combine the advantages of microparticles and nanoparticles using a biocompatible, biodegradable polymer with polycationic nature and inherent immunogenicity that enhances cell targeting. Therefore, this review aims to offer an overview of the recent advances in inhalable chitosan nanocomposites microparticles formulated in the previous five years in terms of primary nanoparticles manufacturing methods; namely, ionic crosslinking of chitosan using tripolyphosphate, electrospinning/electrospraying, layer-by-layer deposition, and nanospray drying; final microparticles manufacturing techniques using spray drying, nano spray drying, and supercritical assisted spray drying; in addition to the process optimization of the previously mentioned manufacturing methods. Furthermore, this review highlights using chitosan and its derivatives in primary nanoparticles preparation and as a polysaccharide to distribute the prepared nanoparticles in microparticles. Finally, this review discusses the factors affecting yield, encapsulation efficiency, in vitro aerosolization properties, size, morphological characters, in vitro release, and in vivo evaluation of inhalable chitosan nanocomposite microparticles.

In Vitro Characterization of Inhalable Cationic Hybrid Nanoparticles as Potential Vaccine Carriers

In this study, PGA-co-PDL nanoparticles (NPs) encapsulating model antigen, bovine serum albumin (BSA), were prepared via double emulsion solvent evaporation. In addition, chitosan hydrochloride (CHL) was incorporated into the external phase of the emulsion solvent method, which resulted in surface adsorption onto the NPs to form hybrid cationic CHL NPs. The BSA encapsulated CHL NPs were encompassed into nanocomposite microcarriers (NCMPs) composed of l-leucine to produce CHL NPs/NCMPs via spray drying. The CHL NPs/NCMPs were investigated for in vitro aerosolization, release study, cell viability and uptake, and stability of protein structure. Hybrid cationic CHL NPs (CHL: 10 mg/mL) of particle size (480.2 ± 32.2 nm), charge (+14.2 ± 0.72 mV), and BSA loading (7.28 ± 1.3 µg/mg) were produced. The adsorption pattern was determined to follow the Freundlich model. Aerosolization of CHL NPs/NCMPs indicated fine particle fraction (FPF: 46.79 ± 11.21%) and mass median aerodynamic diameter (MMAD: 1.49 ± 0.29 µm). The BSA α-helical structure was maintained, after release from the CHL NPs/NCMPs, as indicated by circular dichroism. Furthermore, dendritic cells (DCs) and A549 cells showed good viability (≥70% at 2.5 mg/mL after 4–24 h exposure, respectively). Confocal microscopy and flow cytometry data showed hybrid cationic CHL NPs were successfully taken up by DCs within 1 h of incubation. The upregulation of CD40, CD86, and MHC-II cell surface markers indicated that the DCs were successfully activated by the hybrid cationic CHL NPs. These results suggest that the CHL NPs/NCMPs technology platform could potentially be used for the delivery of proteins to the lungs for immunostimulatory applications such as vaccines.

Design of ciprofloxacin-loaded nano-and microcomposite particles for dry powder inhaler formulations: preparation, in vitro characterisation, and antimicrobial efficacy

In this study, ciprofloxacin hydrochloride (CIP)-loaded poly-ε-caprolactone (PCL) nanoparticles were prepared for pulmonary administration. CIP-loaded PCL nanoparticles were prepared using solid-in-oil-in-water (s/o/w) emulsion solvent evaporation method, and the effects of various formulation parameters on the physicochemical properties of the nanoparticles were investigated. PCL nanoparticles showed spherical shapes with particle sizes around 143-489 nm. Encapsulation efficiency was found to be very low because of water-solubility properties of CIP. However, the surface modification of nanoparticles with chitosan caused an increase in the encapsulation efficiency of nanoparticles. At drug release study, CIP-loaded PCL nanoparticles showed initial burst effect for 4 h and then continuously released for 72 h. Nanocomposite microparticles containing CIP-loaded PCL nanoparticles were prepared freeze-drying method and mannitol was used as carrier material. Tapped density and MMADt results show that nanocomposite microparticles have suitable aerodynamic properties for pulmonary administration. Antimicrobial efficacy investigations showed that CIP-encapsulated PCL nanoparticles and nanocomposite microparticles inhibited the growth of bacteria. Also, when the antimicrobial activity of the nanoparticles at the beginning and at the sixth month was examined, it was found that the structure of the particulate system was still preserved. These results indicated that nanocomposite microparticles containing CIP-loaded PCL nanoparticles can be used for pulmonary delivery.

Quiescent and Agitated Redispersion as a Tool for Evaluating Dispersant Effectiveness in Dissolution Enhancement of Drug-Laden Nanocomposites

Nanocomposite microparticles (NCMPs) have been used in various solid dosage forms with the goal of enhancing the dissolution rate and bioavailability of poorly water-soluble drugs. Nanoparticle recovery from NCMPs, i.e., redispersion, is the preliminary step in drug dissolution. This study aims at exploring aqueous redispersion of NCMPs with various dispersants under quiescent vs. agitated conditions as potential dispersant screening tool in the development of fast-dissolving NCMP formulations. NCMPs were prepared by coating wet-milled suspensions of a poorly water-soluble drug, griseofulvin (GF), formulated with the dispersants hydroxypropyl cellulose (HPC), sodium dodecyl sulfate (SDS), as-received/wet co-milled croscarmellose sodium (CCS), and mannitol, onto Pharmatose® carrier particles in a fluidized bed dryer. The NCMPs were added to quiescent water kept in a cuvette, and the redispersion was visualized and investigated by turbidimetry and dynamic light scattering. The morphological evolution of a single NCMP exposed to a drop of water was studied via optical microscopy, which provided further insight into the self-redispersibility. As a comparison, the NCMPs were also redispersed in water agitated by a paddle stirrer followed by centrifugation and drug assay of the resultant supernatant, which yielded the percentage of GF recovered as nanoparticles. Both quiescent and agitated redispersion methods yielded similar rank-ordering of the dispersants: NCMPs with either HPC/SDS or HPC/CCS exhibited effective nanoparticle recovery and fast dissolution, whereas those with HPC or HPC/mannitol led to poor redispersibility and slow dissolution. This study demonstrates that both quiescent and agitated redispersion tests could be used for screening/optimizing dispersants for fast-dissolving drug NCMP formulations.

Synthesis and Characterization of Nanocomposite Microparticles (nCmP) for the Treatment of Cystic Fibrosis-Related Infections

PURPOSE

Pulmonary antibiotic delivery is recommended as maintenance therapy for cystic fibrosis (CF) patients who experience chronic infections. However, abnormally thick and sticky mucus present in the respiratory tract of CF patients impairs mucus penetration and limits the efficacy of inhaled antibiotics. To overcome the obstacles of pulmonary antibiotic delivery, we have developed nanocomposite microparticles (nCmP) for the inhalation application of antibiotics in the form of dry powder aerosols.

METHODS

Azithromycin-loaded and rapamycin-loaded polymeric nanoparticles (NP) were prepared via nanoprecipitation and nCmP were prepared by spray drying and the physicochemical characteristics were evaluated.

RESULTS

The nanoparticles were 200 nm in diameter both before loading into and after redispersion from nCmP. The NP exhibited smooth, spherical morphology and the nCmP were corrugated spheres about 1 μm in diameter. Both drugs were successfully encapsulated into the NP and were released in a sustained manner. The NP were successfully loaded into nCmP with favorable encapsulation efficacy. All materials were stable at manufacturing and storage conditions and nCmP were in an amorphous state after spray drying. nCmP demonstrated desirable aerosol dispersion characteristics, allowing them to deposit into the deep lung regions for effective drug delivery.

CONCLUSIONS

The described nCmP have the potential to overcome mucus-limited pulmonary delivery of antibiotics.