Characterizing the Surface Roughness Length Scales of Lactose Carrier Particles in Dry Powder Inhalers

Different Carriers for Use in Dry Powder Inhalers: Characteristics of Their Particles

In contemporary times, there has been a rise in the utilization of dry powder inhalers (DPIs) in the management of pulmonary and systemic diseases. These devices underwent a swift advancement in terms of both the equipment utilized and the formulation process. In this review, the carrier physicochemical characteristics that influence DPI performance are discussed, focusing its shape, morphology, size distribution, texture, aerodynamic diameter, density, moisture, adhesive and detachment forces between particles, fine carrier particles, and dry powder aerosolization. To promote the deposition of the active principal ingredient deep within the pulmonary system, advancements have been made in enhancing these factors and surface properties through the application of novel technologies that encompass particle engineering. So far, the most used carrier is lactose showing some advantages and disadvantages, but other substances and systems are being studied with the intention of replacing it. The final objective of this review is to analyze the physicochemical and mechanical characteristics of the different carriers or new delivery systems used in DPI formulations, whether already on the market or still under investigation. [Figure: see text].

Surface Modification of lactose carrier particles using a fluid bed coater to improve fine particle fraction for dry powder inhalers

Surface roughness of carrier particles can impact dry powder inhaler (DPI) performance. There are opposing views on the effect of roughness on DPI performance. Hence, a systematic approach is needed to modify carrier surfaces and evaluate the impact on drug delivery. Carrier particle surfaces were modified by fluid bed coating with saturated lactose containing micronized lactose of different sizes (2, 5 and 8 μm) and coated to different levels (20, 40, 60 and 80%). Their drug delivery performance was assessed by the fine particle fraction (FPF). Roughness parameters, mean arithmetic roughness (R_a) and arithmetic mean height (S_a), of the carrier particles, were also evaluated using optical profilometry and scanning laser microscopy. Generally, particles of higher R_a had higher FPF. Higher S_a resulted in higher FPF only for particles with 60 and 80% coat levels. Reduced contact surface area between the drug particle and rougher carrier particle resulted in easier drug detachment during aerosolization. The 5 µm micronized lactose produced optimal carrier particles with respect to FPF and surface roughness. The study highlighted that with the ideal particles for surface roughening and coating level, surface roughening could be efficiently achieved by fluid bed coating for superior DPI performance.

Mixing of dry powders for inhalation: A review

The process of solids mixing is applied across a considerable range of industries. Pharmaceutical science is one of those industries that utilizes solids mixing extensively. Specifically, solids mixing as a key factor in the preparation of dry powder inhalers using the ordered mixing process will be discussed here. This review opens with a history of dry powder mixing theory, continues to ordered mixing in the preparation for dry powder inhalers, details key interparticulate interactions, explains formulation components for dry powder blends, and finally discusses different types of mixers used in the production of dry powder blends for inhalation. Lastly, the authors offer some suggestions for future work on this topic.

A real-time and modular approach for quick detection and mechanism exploration of DPIs with different carrier particle sizes

Dry powder inhalers (DPIs) had been widely used in lung diseases on account of direct pulmonary delivery, good drug stability and satisfactory patient compliance. However, an indistinct understanding of pulmonary delivery processes (PDPs) hindered the development of DPIs. Most current evaluation methods explored the PDPs with over-simplified models, leading to uncompleted investigations of the whole or partial PDPs. In the present research, an innovative modular process analysis platform (MPAP) was applied to investigate the detailed mechanisms of each PDP of DPIs with different carrier particle sizes (CPS). The MPAP was composed of a laser particle size analyzer, an inhaler device, an artificial throat and a pre-separator, to investigate the fluidization and dispersion, transportation, detachment and deposition process of DPIs. The release profiles of drug, drug aggregation and carrier were monitored in real-time. The influence of CPS on PDPs and corresponding mechanisms were explored. The powder properties of the carriers were investigated by the optical profiler and Freeman Technology four powder rheometer. The next generation impactor was employed to explore the aerosolization performance of DPIs. The novel MPAP was successfully applied in exploring the comprehensive mechanism of PDPs, which had enormous potential to be used to investigate and develop DPIs.

Nanoparticle-Based Drug Delivery System: The Magic Bullet for the Treatment of Chronic Pulmonary Diseases

Chronic pulmonary diseases encompass different persistent and lethal diseases, including chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), cystic fibrosis (CF), asthma, and lung cancers that affect millions of people globally. Traditional pharmacotherapeutic treatment approaches (i.e., bronchodilators, corticosteroids, chemotherapeutics, peptide-based agents, etc.) are not satisfactory to cure or impede diseases. With the advent of nanotechnology, drug delivery to an intended site is still difficult, but the nanoparticle's physicochemical properties can accomplish targeted therapeutic delivery. Based on their surface, size, density, and physical-chemical properties, nanoparticles have demonstrated enhanced pharmacokinetics of actives, achieving the spotlight in the drug delivery research field. In this review, the authors have highlighted different nanoparticle-based therapeutic delivery approaches to treat chronic pulmonary diseases along with the preparation techniques. The authors have remarked the nanosuspension delivery via nebulization and dry powder carrier is further effective in the lung delivery system since the particles released from these systems are innumerable to composite nanoparticles. The authors have also outlined the inhaled particle's toxicity, patented nanoparticle-based pulmonary formulations, and commercial pulmonary drug delivery devices (PDD) in other sections. Recently advanced formulations employing nanoparticles as therapeutic carriers for the efficient treatment of chronic pulmonary diseases are also canvassed.

Microstructural characterization of carrier-based dry powder inhalation excipients: Insights and guidance

The growing interest in development of dry powder inhalation (DPI) products raises a need for development of standard testing methods and specifications for DPI excipients. The pharmaceutical industry, meanwhile, yet lacks compendial guidance on this topic. Despite of the complexity of interactions taking place in DPI systems and the large number and variety of interplaying factors, understanding of key determinants of performance (critical quality attributes) of DPI excipients have considerably developed over the past years. In light of the current knowledge in this area, this article provides technical guidance and insights on testing and quality control of carrier-based-DPI excipients. These excipients are, typically, blends of coarse, carrier particles and fine, performance-modulating particles. The article explores techniques used for measurement of key microstructural attributes, namely the particle size distribution, the porosity and the particle surface roughness, the particle shape, rheological properties, and the permeability, of these excipients. The technical relevance of each measurement to the functionality of the excipients is critically discussed. In this regard, caveats concerning use of some measurements and data analysis procedures are raised. The guidance lends itself for compendial adoption.

Probing the influence of lactose fines, a USP modified induction port and modified DDU apparatus on the aerodynamic behavior of a fluticasone propionate dry powder inhaler

The objective of the present study is to understand the effects of lactose fines, a USP modified induction port (IP) and USP modified glass sampling apparatus (DDU apparatus) on the aerodynamic behavior of a fluticasone propionate (FP) dry powder inhaler (DPI).

Chitosan-based binary dry powder inhaler carrier with nanometer roughness for improving in vitro and in vivo aerosolization performance

Suitable nanometer roughness favors interactions between drugs and carriers, and it is a promising approach to enhance the aerosolization performance of carrier-based dry powder inhalers (DPIs). In this study, by altering the molecular migration rates, chitosan-based binary carriers (CBBCs) with nanometer roughness were fabricated for DPIs. Comprehensive physicochemical characterizations were conducted to elucidate the formation mechanism of the CBBCs. It was hypothesized that different constituent ratios in the formulations would result in different assembling of the particles and diverse roughness scales. The fine particle fractions (FPF, approximately 40~60%) of nanometer roughness CBBC-based DPI formulations were satisfactory, demonstrating the enhancement of the in vitro aerodynamic performance. The positive correlation (R² = 0.9883) between the nanometer roughness and FPF was revealed, and the surface roughness of 20 nm might achieve the best aerosolization performance. CBBCs (optimal formulations) showed no difference in cytotoxicity on A549 and Calu-3 cells (p > 0.05). Additionally, the increased C_max and AUC_0-8h of the formulation with the nanometer roughness (p < 0.05) were observed in pharmacokinetic studies, which resulted from the improved in vivo aerosolization performance. In summary, the CBBCs were a prospective tool to improve the in vitro and in vivo aerosolization performance of DPIs. Graphical abstract ᅟ.