Effective nebulization of interferon-γ using a novel vibrating mesh

Abstract

Background Interferon gamma (IFN-γ) is a clinically relevant immunomodulatory cytokine that has demonstrated significant potential in the treatment and management of respiratory diseases such as tuberculosis and pulmonary fibrosis. As with all large biomolecules, clinical translation is dependent on effective delivery to the disease site and delivery of IFN-γ as an aerosol offers a logical means of drug targeting. Effective localization is often hampered by instability and a lack of safe and efficient delivery systems. The present study sought to determine how effectively IFN-γ can be nebulized using two types of vibrating mesh nebulizer, each with differing mesh architectures, and to investigate the comparative efficiency of delivery of therapeutically active IFN-γ to the lungs. Methods Nebulization of IFN-γ was carried out using two different Aerogen vibrating mesh technologies with differing mesh architectures. These technologies represent both a standard commercially available mesh type (Aerogen Solo®) and a new iteration mesh (Photo-defined aperture plate (PDAP®). Extensive aerosol studies (aerosol output and droplet analysis, non-invasive and invasive aerosol therapy) were conducted in line with regulatory requirements and characterization of the stability and bioactivity of the IFN-γ post-nebulization was confirmed using SDS-PAGE and stimulation of Human C-X-C motif chemokine 10 (CXCL 10) also known as IFN-γ-induced protein 10KDa (IP 10) expression from THP-1 derived macrophages (THP-1 cells). Results Aerosol characterization studies indicated that a significant and reproducible dose of aerosolized IFN-γ can be delivered using both vibrating mesh technologies. Nebulization using both devices resulted in an emitted dose of at least 93% (100% dose minus residual volume) for IFN-γ. Characterization of aerosolized IFN-γ indicated that the PDAP was capable of generating droplets with a significantly lower mass median aerodynamic diameter (MMAD) with values of 2.79 ± 0.29 μm and 4.39 ± 0.25 μm for the PDAP and Solo respectively. The volume median diameters (VMD) of aerosolized IFN-γ corroborated this with VMDs of 2.33 ± 0.02 μm for the PDAP and 4.30 ± 0.02 μm for the Solo. SDS-PAGE gels indicated that IFN-γ remains stable after nebulization by both devices and this was confirmed by bioactivity studies using a THP-1 cell model in which an alveolar macrophage response to IFN-γ was determined. IFN-γ nebulized by the PDAP and Solo devices had no significant effect on the key inflammatory biomarker cytokine IP-10 release from this model in comparison to non-nebulized controls. Here we demonstrate that it is possible to combine IFN-γ with vibrating mesh nebulizer devices and facilitate effective aerosolisation with minimal impact on IFN-γ structure or bioactivity. Conclusions It is possible to nebulize IFN-γ effectively with vibrating mesh nebulizer devices without compromising its stability. The PDAP allows for ge...

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“…Aerogen have developed a new mesh technology, photo defined aperture plate or PDAP, a two-layer nebulizer with 15,600 preformed holes compared to their Pro device with 1000 holes. The PDAP nebulizer generates low droplet sizes with faster flow rates [50]. Refinements of this nature have the potential to improve patient outcomes by improving drug deposition in the lower airways whilst also reducing treatment times.…”

“…VMN are quiet and portable which confers benefits in both home and ICU settings [ 47 ]. VMN are associated with low residual drug volumes [ 22 , 50 ] and greater inhaled mass in models of in vitro invasive ventilation [ 51 ]. Aerosol particles in the size range of ~2–6 μm are suited to maximal tracheobronchial deposition while smaller particles within the range ~0.5–3 μm are maximally suited to alveolar deposition in the alveoli [ 2 ].…”

“…Other molecules such as interferon-gamma (INF-γ), a macrophage stimulator factor, also produced by MSCs, have been proven retain bioactivity after nebulization. Sweeney et al (2019) showed that VMN produced aerosol of purified INF-γ retained molecule stability and activity in an in vitro study with the THP-1 macrophage cell line [ 50 ]. Similarly, nebulized INF-γ has greater effect compared to parenteral delivery in idiopathic pulmonary fibrosis patients in a controlled clinical trial [ 173 , 174 ].…”

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“…On the other hand, mesh nebulisers appear to maintain protein integrity to a greater extent than other nebulisers [ 32 ]. Safe aerosolisation with mesh nebulisers has already been demonstrated in several studies of labile drugs including proteins and mAbs [ 33 – 38 ]. The detailed designs and comparisons of various types of nebulizers have been reviewed previously and we will not elaborate further here [ 25 , 30 – 32 , 39 ].…”

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“…These nebulisers function in a manner modified from previous ultrasonic nebulisers, whereby a plate containing approximately 1000 tapered holes vibrates at a frequency of roughly 128 kHz, thereby causing the ejection of liquid droplets [ 17 ]. Vibrating mesh nebulisers are now becoming widespread and there is investigation into their use for delivery of sensitive therapeutic cargoes, such as proteins [ 18 ], miRNA and anti-miRNA target site-blocking oligonucleotides [ 19 , 20 ], mRNA [ 21 ] and siRNA [ 22 , 23 ]. Furthermore, the bulk of recent publications indicate that VMNs deliver more drug to the patient with significantly less wastage, than the more prevalent air-jet nebulisers [ 24 , 25 , 26 ].…”