Development and in vitro characterization of a novel pMDI diclofenac formulation as an inhalable anti-inflammatory therapy for cystic fibrosis

The development of a 3D-printed in vitro integrated oro-pharyngeal air-liquid interface cellular throat model for drug transport

To simulate the deposition of drugs in the oro-pharynx region, several in vitro models are available such as the United States Pharmacopeia-Induction Port (USP-IP) throat and the Virginia Commonwealth University (VCU) models. However, currently, there is no such in vitro model that incorporates a biological barrier to elucidate drug transport across the pharyngeal cells. Cellular models such as in vitro air-liquid interface (ALI) models of human respiratory epithelial cell lines are extensively used to study drug transport. To date, no studies have yet been performed to optimise the ALI culture conditions of the human pharyngeal cell line Detroit 562 and determine whether it could be used for drug transport. Therefore, this study aimed to develop a novel 3D-printed throat model integrated with an ALI cellular model of Detroit 562 cells and optimise the culture conditions to investigate whether the combined model could be used to study drug transport, using Lidocaine as a model drug. Differentiating characteristics specific to airway epithelia were assessed using 3 seeding densities (30,000, 60,000, and 80,000 cells/well (c/w), respectively) over 21 days. The results showed that Detroit 562 cells completely differentiates on day 18 of ALI for both 60,000 and 80,000 c/w with significant mucus production, showing response to bacterial and viral stimuli and development of functional tight junctions and Lidocaine transport with no significant differences observed between the ALI models with the 2 cell seeding densities. Results showed the suitability of the Low density (60,000 c/w or 1.8 × 10⁵ cells/cm²) ALI model to study drug transport. Importantly, the developed novel 3D-printed throat model integrated with our optimised in vitro Detroit 562 ALI model showed transport of Lidocaine throat spray. Overall, the study highlights the potential of the novel 3D-printed bio-throat integrated model as a promising in vitro system to investigate the transport of inhalable drug therapies targeted at the oro-pharyngeal region.

Development of Inhalable Spray Dried Nitrofurantoin Formulations for the Treatment of Emphysema

A central characteristic of emphysematous progression is the continuous destruction of the lung extracellular matrix (ECM). Current treatments for emphysema have only addressed symptoms rather than preventing or reversing the loss of lung ECM. Nitrofurantoin (NF) is an antibiotic that has the potential to induce lung fibrosis as a side effect upon oral administration. Our study aims to repurpose NF as an inhalable therapeutic strategy to upregulate ECM expression, thereby reversing the disease progression within the emphysematous lung. Spray-dried (SD) formulations of NF were prepared in conjunction with a two-fluid nozzle (2FN) and three-fluid nozzle (3FN) using hydroxypropyl methylcellulose (HPMC) and NF at 1:1 w/w. The formulations were characterized for their physicochemical properties (particle size, morphology, solid-state characteristics, aerodynamic behaviour, and dissolution properties) and characterized in vitro with efficacy studies on human lung fibroblasts. The 2FN formulation displayed a mass mean aerodynamic diameter (MMAD) of 1.8 ± 0.05 µm and fine particle fraction (FPF) of 87.4 ± 2.8% with significantly greater deposition predicted in the lower lung region compared to the 3FN formulation (MMAD: 4.4 ± 0.4 µm; FPF: 40 ± 5.8%). Furthermore, drug dissolution studies showed that NF released from the 2FN formulation after 3 h was significantly higher (55.7%) as compared to the 3FN formulation (42.4%). Importantly, efficacy studies in human lung fibroblasts showed that the 2FN formulation induced significantly enhanced ECM protein expression levels of periostin and Type IV Collagen (203.2% and 84.2% increase, respectively) compared to untreated cells, while 3FN formulations induced only a 172.5% increase in periostin and a 38.1% increase in type IV collagen. In conclusion, our study highlights the influence of nozzle choice in inhalable spray-dried formulations and supports the feasibility of using SD NF prepared using 2FN as a potential inhalable therapeutic agent to upregulate ECM protein production.

Development of excipients free inhalable co-spray-dried tobramycin and diclofenac formulations for cystic fibrosis using two and three fluid nozzles

This study aims to investigate the effect of physicochemical properties and aerosol performance of two (2FN) and three-fluid nozzles (3FN) on the inhalable co-formulation of tobramycin and diclofenac dry powders. Combination formulations of tobramycin and diclofenac at 2:1 and 4:1 w/w ratios were prepared at a laboratory scale using a spray dryer in conjunction with a 2FN or 3FN. Powder size, morphology, solid-state characteristics, and aerodynamic and dissolution properties were characterised. The nozzle types and the formulation composition influenced the yield, particle size, solid-state properties, aerosolization behaviour and dissolution of the co-spray dried formulations. In particular, using the 2FN the co-spray dried formulation of tobramycin and diclofenac at 2:1 w/w showed smaller particle size (D50, 3.01 ± 0.06 μm), high fine particle fractions (FPF) (61.1 ± 3.6% for tobramycin and 65.92 ± 3 for diclofenac) and faster dissolution with approx. 70% diclofenac released within 3 h and approx. 90% tobramycin was released within 45 min. However, the 3FN for the co-spray dried formulation of tobramycin and diclofenac at a 2:1 w/w ratio showed a larger particle size (D50, 3.42 ± 0.02 μm), lower FPF (40.6 ± 3.4% for tobramycin and 36.9 ± 0.84 for diclofenac) and comparative slower dissolution with approx. 60% diclofenac was released within 3 h and 80% tobramycin was released within 45 min. A similar trend was observed when the tobramycin to diclofenac ratio was increased to 4:1 w/w. Overall results suggest that spray drying with 2FN showed a superior and viable approach to producing excipients-free inhalable co-spray dried formulations of tobramycin and diclofenac. However, the formulation produced using the 3FN showed higher enrichment of hydrophobic diclofenac and an ability to control the tobramycin drug release in vitro.

Nanotechnology-Assisted Metered-Dose Inhalers (MDIs) for High-Performance Pulmonary Drug Delivery Applications

PURPOSE

Respiratory disorders pose a major threat to the morbidity and mortality to public health. Here we reviewed the nanotechnology based pulmonary drug delivery using metered dose inhalers.

METHODS

Major respiratory diseases such as chronic obstructive pulmonary diseases (COPD), asthma, acute lower respiratory tract infections, tuberculosis (TB) and lung cancer. At present, common treatments for respiratory disorders include surgery, radiation, immunotherapy, and chemotherapy or a combination. The major challenge is development of systemic delivery of the chemotherapeutic agents to the respiratory system. Conventional delivery of chemotherapy has various limitation and adverse side effected. Hence, targeted, and systemic delivery need to be developed. Towards this direction nanotechnology, based controlled, targeted, and systemic drug delivery systems are potential candidate to enhance therapeutic efficacy with minimum side effect. Among different route of administration, pulmonary delivery has unique benefits such as circumvents first pass hepatic metabolism and reduces dose and side effects.

RESULTS

Respiratory disorders pose a major threat to the morbidity and mortality to public health globally. Pulmonary delivery can be achieved through various drug delivery devices such as nebulizers, dry powder inhalers, and metered dose inhalers. Among them, metered dose inhalers are the most interesting and first choice of clinician over others. This review focused on nanotechnology based pulmonary drug delivery using metered dose inhalers. This report focused on delivery of various types of therapeutics using nanocarriers such as polymeric nanoparticles and micelles, dendrimers, lipid nanocarriers such as liposomes, solid lipid nanostructures and nanostructured lipid carriers, and other using metered dose inhalers discussed comprehensively. This report provides insight about the effect of parameters of MDI such as co-solvent, propellants, actuators shape, nozzle diameters, and jet lengths, and respiratory flow rate, and particle size of co-suspension of drug on aerodynamics and lung deposition of formulation. This review also provided the insight about various metered dose inhalers market scenario and digital metered dose inhalers.

CONCLUSION

This report concluded the clinical potential of metered dose inhalers, summary of current progress and future perspectives towards the smart digital metered dose inhalers development.