Tuning aerosol particle size distribution of metered dose inhalers using cosolvents and surfactants

OBJECTIVES: The purpose of these studies was to understand the influence of cosolvent and surfactant contributions to particle size distributions emitted from solution metered dose inhalers (pMDIs) based on the propellant HFA 227. METHODS: Two sets of formulations were prepared: (a) pMDIs-HFA 227 containing cosolvent (5-15% w/w ethanol) with constant surfactant (pluronic) concentration and (b) pMDIs-HFA 227 containing surfactant (0-5.45% w/w pluronic) with constant cosolvent concentration. Particle size distributions emitted from these pMDIs were analyzed using aerodynamic characterization (inertial impaction) and laser diffraction methods. RESULTS: Both cosolvent and surfactant concentrations were positively correlated with median particle sizes; that is, drug particle size increased with increasing ethanol and pluronic concentrations. However, evaluation of particle size distributions showed that cosolvent caused reduction in the fine particle mode magnitude while the surfactant caused a shift in the mode position. These findings highlight the different mechanisms by which these components influence droplet formation and demonstrate the ability to utilize the different effects in formulations of pMDI-HFA 227 for independently modulating particle sizes in the respirable region. CONCLUSION: Potentially, the formulation design window generated using these excipients in combination could be used to match the particle size output of reformulated products to preexisting pMDI products

Insight into inclusion complexation of indomethacin nicotinamide cocrystals

The objective of this research was to investigate the feasibility of the interaction between indomethacin-nicotinamide cocrystals with β-cyclodextrin and hydroxypropyl-β-cyclodextrin in the solid-state. The study has emphasized on the possibility of inclusion complex formation and its effect on the dissolution performance of the cocrystals. The solid systems in the molar ratio of 1:1 of the host and guest molecules were prepared by co-grinding and co-evaporation methods and compared with their physical mixtures. Furthermore, the molecular behaviors of the cocrystals in all prepared samples were thoroughly characterized by powder X-ray diffraction, differential scanning calorimetry, Fourier-transform infrared spectroscopy, scanning electron microscopy and in-vitro dissolution performance. The results of these studies indicated that complexes prepared by the co-evaporation method with hydroxypropyl-β-cyclodextrin have shown complete inclusion of the cocrystals into the cyclodextrin cavity and a partial inclusion with β-cyclodextrin. Moreover, a significant (p < 0.05; ANOVA/Tukey) higher in-vitro dissolution was achieved in co-evaporate complex prepared with hydroxypropyl-β-cyclodextrin compared to that prepared with β-cyclodextrin, indomethacin-nicotinamide cocrystals and indomethacin itself

Recent Advances Using Supercritical Fluid Techniques for Pulmonary Administration of Macromolecules via Dry Powder Formulations

Growing demands on a suitable formulation method that ensures the stability of the active compound coupled with the limitations of current methods (milling, lyophilization, spray drying, and freeze spray drying) has brought wide attention to supercritical fluid (SCF) technology. Advantages of using the SCF technology comprise its high abilities, adaptability in providing alternative processing methods, high compressibility and diffusivity of the supercritical fluid, capability as an alternative for conventional organic solvents, and the option to attain different processing parameters which would be otherwise difficult to conduct with traditional methods. This review proposes to present an up-to-date outlook on dry powder pulmonary formulations of macromolecules using SCF technology

Nanocarriers Targeting Dendritic Cells for Pulmonary Vaccine Delivery

Pulmonary vaccine delivery has gained significant attention as an alternate route for vaccination without the use of needles. Immunization through the pulmonary route induces both mucosal and systemic immunity, and the delivery of antigens in a dry powder state can overcome some challenges such as cold-chain and availability of medical personnel compared to traditional liquid-based vaccines. Antigens formulated as nanoparticles (NPs) reach the respiratory airways of the lungs providing greater chance of uptake by relevant immune cells. In addition, effective targeting of antigens to the most ‘professional’ antigen presenting cells (APCs), the dendritic cells (DCs) yields an enhanced immune response and the use of an adjuvant further augments the generated immune response thus requiring less antigen/dosage to achieve vaccination. This review discusses the pulmonary delivery of vaccines, methods of preparing NPs for antigen delivery and targeting, the importance of targeting DCs and different techniques involved in formulating dry powders suitable for inhalation

Nanocarriers Targeting Dendritic Cells for Pulmonary Vaccine Delivery

Pulmonary vaccine delivery has gained significant attention as an alternate route for vaccination without the use of needles. Immunization through the pulmonary route induces both mucosal and systemic immunity, and the delivery of antigens in a dry powder state can overcome some challenges such as cold-chain and availability of medical personnel compared to traditional liquid-based vaccines. Antigens formulated as nanoparticles (NPs) reach the respiratory airways of the lungs providing greater chance of uptake by relevant immune cells. In addition, effective targeting of antigens to the most ‘professional’ antigen presenting cells (APCs), the dendritic cells (DCs) yields an enhanced immune response and the use of an adjuvant further augments the generated immune response thus requiring less antigen/dosage to achieve vaccination. This review discusses the pulmonary delivery of vaccines, methods of preparing NPs for antigen delivery and targeting, the importance of targeting DCs and different techniques involved in formulating dry powders suitable for inhalation

In Vitro Evaluation of Eudragit Matrices for Oral Delivery of BCG Vaccine to Animals

Bacillus Calmette–Guérin (BCG) vaccine is the only licensed vaccine against tuberculosis (TB) in humans and animals. It is most commonly administered parenterally, but oral delivery is highly advantageous for the immunisation of cattle and wildlife hosts of TB in particular. Since BCG is susceptible to inactivation in the gut, vaccine formulations were prepared from suspensions of Eudragit L100 copolymer powder and BCG in phosphate-buffered saline (PBS), containing Tween® 80, with and without the addition of mannitol or trehalose. Samples were frozen at −20 °C, freeze-dried and the lyophilised powders were compressed to produce BCG–Eudragit matrices. Production of the dried powders resulted in a reduction in BCG viability. Substantial losses in viability occurred at the initial formulation stage and at the stage of powder compaction. Data indicated that the Eudragit matrix protected BCG against simulated gastric fluid (SGF). The matrices remained intact in SGF and dissolved completely in simulated intestinal fluid (SIF) within three hours. The inclusion of mannitol or trehalose in the matrix provided additional protection to BCG during freeze-drying. Control needs to be exercised over BCG aggregation, freeze-drying and powder compaction conditions to minimise physical damage of the bacterial cell wall and maximise the viability of oral BCG vaccines prepared by dry powder compaction

Polymeric Nanoparticles for the Delivery of miRNA to Treat Chronic Obstructive Pulmonary Disease (COPD).

RNA interference (RNAi) based therapeutics are considered an endogenous mechanism for modulating gene expression. In addition, microRNAs (miRNAs) may be tractable targets for the treatment of Chronic Obstructive Pulmonary Disease (COPD). In this study miR146a was adsorbed onto poly (glycerol adipate-co-ω-pentadecalactone), PGA-co-PDL, nanoparticles (NPs) to reduce target gene IRAK1 expression. NPs were prepared using an oil-in-water single emulsion solvent evaporation method incorporating cationic lipid dioleoyltrimethylammoniumpropane (DOTAP). This resulted in NPs of 244.80±4.40 nm at 15 % DOTAP concentration, zeta potential (ZP) of +14.8±0.26 mV and miR-146a (40 µg/ml) maximum adsorption onto 15 % DOTAP NPs was 36.25±0.35 µg per 10 mg NP following 24 h incubation. Using the MTT assay, it was observed that over 75 % at 0.312 mg/ml of A549 cells remained viable after 18 h exposure to cationic NPs at a concentration of 1.25 mg/ml. Furthermore, the in vitro release profile of miR-146a from loaded NPs showed a continuous release up to 77 % after 24 h. Internalization of miR-146a loaded cationic NPs was observed in A549 cell lines using fluorescence and confocal microscopy. The miR146a delivered as miR-146a-NPs had a dose dependent effect of highest NPs concentrations 0.321 and 0.625 mg/ml and reduced target gene IRAK1 expression to 40 %. In addition, IL-8 promoter reporter output (GFP) was dampened by miR-146a-NPs. In conclusion, miR-146a was successfully adsorbed onto PGA-co-PDL-DOTAP NPs and the miR-146a retained biological activity. Therefore, these results demonstrate the potential of PGA-co-PDL NPs as a delivery system for miR-146a to treat COPD

Exploiting gelatin nanocarriers in the pulmonary delivery of methotrexate for lung cancer therapy.

Gelatin has many merits that encourage its use in the pulmonary delivery of anticancer drugs. It is a biodegradable denatured protein which possesses several functional groups that could be modified. Additionally, it has balanced hydrophilic and hydrophobic characters, which facilitate the loading of chemotherapeutic agents. Accordingly, the purpose of the current work was to exploit this valuable biomaterial in the efficient pulmonary delivery of methotrexate in case of lung cancer. Gelatin nanoparticles were prepared via a desolvation method and the fabrication process was optimized using Box Behnken design of experiment. A comparative study on uptake of gelatin nanoparticles by lung adenocarcinoma cells and macrophages was implemented using flow cytometry. Investigation of the effect of different methotrexate loading techniques: encapsulation, post loading and chemical conjugation on the nanoparticles characteristics and cellular cytotoxicity was performed. Nano-in-microparticles were prepared by co-spray drying optimized nanoparticles with leucine. Results showed that Box Behnken design was able to optimize preparation parameters to yield uniform nanoparticles with suitable particle size for cancer cells uptake. The prepared nanoparticles demonstrated a preferential uptake by lung cancer cells. Additionally, methotrexate loaded nanoparticles demonstrated up to four fold significant reduction in methotrexate IC50. The spray dried gelatin nano-in microparticles demonstrated good aerosolization properties enabling lung deposition in the respirable airways. Thus, providing a promising platform for lung cancer therapy