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Pulmonary drug delivery (PDD) has potential for both local and systemic therapy. Our research group is focus- ing on the development of dry powder inhalation (DPI) systems for PDD due to their beneficial properties. Although there is not yet a marketed inhalation product for non-steroidal anti-inflammatory drugs (NSAIDs), their therapeutic use in sev- eral lung diseases is well established and successful DPI developments have been performed with them. Sodium stearate (NaSt) is a promising excipient for DPI development, but its role in NSAIDs has not yet been investigated. Thus, the aim was to study DPI samples produced by co-spray-drying, applying meloxicam potassium (MXP) as an NSAID drug, and different concentrations (0-2 w/w%) of NaSt. Physicochemical investigations, in vitro lung deposition, and in vitro drug release measurements were performed. It can be stated that co-spray-drying of MXP with NaSt resulted in remarkable morphological differences by increasing the concentration of NaSt, which had a positive effect on cohesive work. Further- more, applying of NaSt accelerates the dissolution in simulated lung fluid (SLF). NaSt as excipient has a future for the formulation of the DPI systems because there are in the development focus the attaintment of the higher FPF values and improvement of dissolution in SLF.

In this study, the aerogel technology was used to prepare pulmonary drug carriers consisting of alginate and alginate-hyaluronic acid by an emulsion gelation technique and supercritical CO2 drying. During the preparation process, the emulsification rate and inner phase viscosity were varied to control the diameter of aerogel microspheres. Results showed that the aerogel microspheres were highly porous (porosity > 98%) with low densities in the range between 0.0087 and 0.0634 g/cm3 as well as high surface areas between 354 and 759 m2/g. The obtained microspheres showed aerodynamic diameter below 5 µm making them suitable for pulmonary drug delivery. An in vitro drug release study with the model drug sodium naproxen was conducted and a non-Fickian drug release mechanism was observed, with no significant difference between the release profiles of alginate and alginate-hyaluronic acid microspheres. During the emulsion gelation step, the feasibility of using the capillary number to estimate the largest stable droplet size in the emulsions was also studied and it was found that using this number, the droplet size in the emulsions may well be predicted.

Existing therapies yield low drug encapsulation or accumulation in the lungs, hence the site-specific drug delivery remains the challenge for tuberculosis. Lately, dry powder inhalers (DPIs) are showing promising drug deposition in the deeper lung tissues. Biocompatible polymers with the ability to naturally recognize and bind to the surface receptors of alveolar macrophages, the reservoir of the causative organism, were selected. DPIs comprised of chitosan (CS)/thiolated chitosan (TC) in conjugation with Hyaluronic acid (HA) were synthesized loaded with isoniazid (INH) by using the Design of Experiment (DoE) approach. Nanosuspensions were prepared by ionic gelation method using cross-linker, sodium-tripolyphosphate (TPP) and were optimized by using Box-Behnken 3-level screening design and later freeze-dried to obtain nanopowders. Physico-chemical compatibility of nanoplex systems was investigated using in-vitro characterization techniques. In-vitro release and permeation studies were correlated in terms of the pattern of drug content dissolved over time. In addition, the cytotoxicity studies on A549 cells demonstrated the safety profile of the nanoplexes. Moreover, in-silico studies and aerodynamic profiles verify the suitability of DPIs for further in-vivo tuberculosis therapeutics. DoE analyses affirmed the lack of linearity in the model for the certain response of studied parameters in a holistic way, which was not possible else ways.

The aim of the present study was the preparation of aerogel microspheres based on alginate and hyaluronic acid for the potential application in pulmonary drug delivery. Both polymers are commonly used in the pharmaceutical and medical fields because of their nontoxicity, biodegradability and biocompatibility characteristics. The bio-based microspheres were produced using an emulsion gelation process with a subsequent drying step by supercritical CO2. The microspheres were characterized by FTIR and SEM. Furthermore, their BET surface area, particle size distribution, and their aerodynamic properties were determined. The microspheres showed a low density in the range of 0.035 – 0.063 g/cm3 and a high porosity of 97.6–98.7 %, as well as good in vitro aerodynamic properties with dA values of about 5 μm. The obtained properties of the alginate- hyaluronic acid microspheres suggest that they are potentially suitable as drug carrier for pulmonary delivery.

Objective: The aim was to study the stability of dry powder inhaler (DPI) formulations containing antibiotic with different preparation ways – carrier-based, carrier-free, and novel combined formul...

In the case of capsule-based dry powder inhalation systems (DPIs), the selection of the appropriate capsule is important. The use of gelatin, gelatin-PEG, and HPMC capsules has become widespread in marketed capsule-based DPIs. We aimed to perform a stability test according to the ICH guideline in the above-mentioned three capsule types. The results of the novel combined formulated microcomposite were more favorable than those of the carrier-free formulation for all capsule types. The use of HPMC capsules results in the greatest stability and thus the best in vitro aerodynamic results for both DPI powders after six months. This can be explained by the fact that the residual solvent content (RSC) of the capsules differs. Under the applied conditions the RSC of the HPMC capsule decreased the least and remained within the optimal range, thus becoming less fragmented, which was reflected in the RSC, structure and morphology of the particles, as well as in the in vitro aerodynamic results (there was a difference of approximately 10% in the lung deposition results). During pharmaceutical dosage form developments, emphasis should be placed in the case of DPIs on determining which capsule type will be used for specific formulations.

Dry Powder Inhaler (DPI) could offer a propellant-free, easy-to-use powder form ensuring better stability than liquid dosage forms. Therefore the development of traditional carrier-based and carrier-free new generation systems is a determinative factor in the field of DPI formulation. The purpose of our research work was to combine these two systems, utilizing their beneficial properties to produce a novel pulmonary drug delivery system containing ciprofloxacin hydrochloride (CIP). Co-spray drying, surface smoothing and the preparation of an interactive physical mixture were applied as the technological procedures of sample preparation. The carrier-based and carrier-free formulations, as well as the developed novel product were compared to each other. Structural investigations were made by X-ray powder diffraction and micrometric properties (habit, bulk density) were determined. Particle interactions were also evaluated to investigate surface free energy, cohesive-adhesive forces, and spreading coefficient. In vitro aerodynamic properties (mass median aerodynamic diameter), fine particle fraction (FPF) and emitted dose of DPIs were measured using Andersen Cascade Impactor. A novel in silico Stochastic Lung Model was also used to quantify the amount of particles deposited at the target area. The novel-formulated composition presented amorphous spherical particles with an average size of about 2 μm. The in vitro aerodynamic investigations showed a variance in FPF as a function of formulation method (carrier-based: 24%, carrier-free: 54% and applying the novel combination method: 63%). The in silico deposition results were in line with the in vitro measurements and yielded increased lung doses for the sample prepared by the combined technology. This novel DPI formulation provides an opportunity for a more effective therapy with deeper deposition of CIP.