In vitro aerosol performance and dose uniformity between the Foradile Aerolizer and the Oxis Turbuhaler

The role of capsule aperture size on the dispersion of carrier-based formulation at different air flowrates

The effect of capsule aperture size on the aerosol performance of lactose blend formulation was studied using Foradil® (containing 12 μg of formoterol fumarate (FF¹) and 24 mg of lactose) dispersed with a powder inhaler Aerolizer® at increasing air flowrates. Apertures sizes of 0.4, 1.0, 1.5, 2.5, and 4.0 mm were introduced at the opposite ends of the capsule. The formulation was dispersed into a Next Generation Impactor (NGI) at 30, 60 and 90 L/min, with the fine particle fractions (FPF_rec and FPF_em) measured by chemical assay of FF and lactose using high-performance liquid chromatography. Particle size distribution (PSD) of FF particles dispersed in wet media was also characterized by laser diffraction. FPF_rec showed a stronger dependency on the flowrate than the capsule aperture size. The most efficient dispersion was achieved at 90 L/min. At a given flowrate, FPF_em remained broadly constant across different aperture sizes. The laser diffraction studies demonstrated the presence of large agglomerates.

Spray Freeze-Drying for inhalation application: Process and Formulation Variables

High porous particles with specific aerodynamic properties were processed by the spray freeze-drying (SFD) method. Comprehensive knowledge about all aspects of the SFD method is required for particle engineering of various pharmaceutical products with good flow properties. In this review, different types of the SFD method, the most frequently employed excipients, properties of particles prepared by this method, and most recent approaches concerning SFD are summarized. Generally, this technique can prepare spherical-shaped particles with a highly porous interior structure, responsible for the very low density of powders. Increasing the solubility of spray freeze-dried formulations achieves the desired efficacy. Also, due to the high efficiency of SFD, by determining the different features of this method and optimizing the process by model-based studies, desirable results for various inhaled products can be achieved and significant progress can be made in the field of pulmonary drug delivery.

Storage stability of inhalable, controlled-release powder formulations of ciprofloxacin nanocrystal-containing liposomes

Novel inhalable and controlled release powder formulations of ciprofloxacin nanocrystals inside liposomes (CNL) were recently developed. In the present study, the storage stability of CNL powders consisting of lyoprotectant (i.e. sucrose or lactose), lipids, ciprofloxacin (CIP), and magnesium stearate or isoleucine was investigated. These powders were produced by spray drying, collected in a dry box at <15% relative humidity (RH), then stored at room temperature and either 4 or 20 %RH. Liposomal integrity, CIP encapsulation efficiency (EE), in vitro drug release (IVR), aerosol performance, and solid-state properties were examined over six months. Sucrose CNL powder exhibited consistent liposomal integrity, aerosol performance, and controlled release of CIP over six months of storage at 4 %RH. However, storage of the powder at 20 %RH for the same period caused sucrose crystallization and consequently a significant drop in EE and aerosol performance (p-values < 0.05), along with the IVR of CIP becoming similar to that of the non-crystalline CIP liposomal dispersions (f2 > 50). Lactose CNL maintained superior aerosol performance over the six months irrespective of the storage RH. However, liposomal instability occurred at both RHs within the first month of storage with a significant drop in EE and an increase in liposome size (p-values < 0.05). Moreover, the IVR assay of CIP from lactose CNL showed a less controlled release and a substantial difference (f2 < 50) from its initial value after six months regardless of the storage RHs. In conclusion, dry powder inhalers of CNL were physiochemically stable in sucrose lyoprotectant when stored below 4 %RH at room temperature for six months.

In vitro and in vivo performance modelling and optimisation of different dry powder inhalers: A complementary study of neural networks, genetic algorithms and decision trees

INTRODUCTION

Aerosol delivery from DPIs could be affected by different factors. This study aimed to evaluate and predict the effects of different factors on drug delivery from DPIs.

METHODS

Modelling and optimisation for both in vitro and in vivo data of different DPIs (Diskus, Turbohaler and Aerolizer) were carried out using neural networks associated with genetic algorithms and the results are confirmed using a decision tree (DT) and random forest regressor (RFR). All variables (the type of DPI, inhalation flow, inhalation volume, number of inhalations and type of subject) were coded as numbers before using them in the modelling study.

RESULTS

The analysis of the in vitro model showed that Turbohaler had the highest emitted dose compared with the Diskus and the Aerolizer. Increasing flow resulted in a gradual increase in the emitted dose. Little differences between the inhalation volumes 2 and 4 litres were shown at fast inhalation flow, and interestingly two inhalations showed somewhat higher emitted doses than one-inhalation mode with Turbohaler and Diskus at slow inhalation flow. Regarding the in vivo model, the percent of drug delivered to the lung was highly increased with Turbohaler and Diskus in healthy subjects where continuous contour lines were observed. The Turbohaler showed increased lung bioavailability with the two-inhalation modes, the Diskus showed a nearly constant level at both one and two inhalations at slow inhalation. The Turbohaler and Aerolizer showed little increasing effect moving from one to two inhalations at slow inhalation.

CONCLUSIONS

Modelling of the input data showed a good differentiating and prediction power for both in vitro and in vivo models. The results of the modelling refer to the high efficacy of Diskus followed by Turbohaler for delivering aerosol. With two inhalations, the three DPIs showed an increase in the percent of drug excreted at slow inhalations.

Inhalable liposomal powder formulations for co-delivery of synergistic ciprofloxacin and colistin against multi-drug resistant gram-negative lung infections

The aim of this study was to design and characterize dry powder inhaler formulations of ciprofloxacin and colistin co-loaded liposomes prepared by the ultrasonic spray-freeze-drying (USFD) technique. Liposomal formulations and powder production parameters were optimized to achieve optimal characteristics and in-vitro performance such as encapsulation efficiency (EE), particle size, particle distribution index (PDI), fine particle fraction (FPF), emitted dose (ED) and in vitro antibacterial activity. The formulation (F6) with the mannitol (5% w/v) as the internal lyoprotectant and sucrose (5%, w/v), mannitol (10%, w/v) and leucine (5%, w/w) as the external lyoprotectants/aerosolization enhancers showed an optimal rehydrated EE values of ciprofloxacin and colistin (44.9 ± 0.9% and 47.0 ± 0.6%, respectively) as well as satisfactory aerosol performance (FPF: 45.8 ± 2.2% and 43.6 ± 1.6%, respectively; ED: 97.0 ± 0.5% and 95.0 ± 0.6%, respectively). For the blank liposomes, there was almost no inhibitory effect on the cell proliferation in human lung epithelial A549 cells, showing that the lipid materials used in the liposome formulation is safe for use in pulmonary drug delivery. The cytotoxicity study demonstrated that the optimized liposomal formulation (F6) was not cytotoxic at least at the drug concentrations of colistin 5 μg/mL and ciprofloxacin 20 μg/mL. Colistin (2 mg/L) monotherapy showed no antibacterial effect against P. aeruginosa H131300444 and H133880624. Ciprofloxacin (8 mg/L) monotherapy showed moderate bacterial killing for both clinical isolates; however, regrowth was observed in 6 h for P. aeruginosa H133880624. The liposomal formulation displayed superior antibacterial activity against clinical isolates of Pseudomonas aeruginosa H131300444 and P. aeruginosa H133880624 compared to each antibiotic per se. These results demonstrate that the liposomal powder formulation prepared by USFD could potentially be a pulmonary delivery system for antibiotic combination to treat multi-drug resistant Gram-negative lung infections.

Formation of ciprofloxacin nanocrystals within liposomes by spray drying for controlled release via inhalation

The present study was conducted to harness spray drying technology as a novel method of producing Ciprofloxacin nanocrystals inside liposomes (CNL) for inhalation delivery. Liposomal ciprofloxacin dispersions were spray dried with sucrose as a lyoprotectant in different mass ratios (0.5:1, 1:1 and 2:1 sucrose to lipids), along with 2% w/w magnesium stearate and 5% w/w isoleucine as aerosolization enhancers. Spray drying conditions were: inlet air temperature 50 °C, outlet air temperature 33-35 °C, atomizer rate 742 L/h and aspirator 35 m³/h. After spray drying, the formation of ciprofloxacin nanocrystals inside the liposomes was confirmed by cryo- transmission electron microscopy. The physiochemical characteristics of the spray dried powder (particle size, morphology, crystallinity, moisture content, drug encapsulation efficiency (EE), in vitro aerosolization performance and drug release) were determined. The EE of the liposomes was found to vary between 44 and 87% w/w as the sucrose content was increased from 25 to 57% w/w. The powders contained partially crystalline particles with a volume median diameter of ~1 µm. The powders had low water content (~2% wt.) and were stable at high relative humidity. Aerosol delivery using the Osmohaler® inhaler at a flow rate of 100 L/min produced an aerosol fine particle fraction (% wt. <5 µm) of 58-64%. The formulation with the highest sucrose content (2:1 w/w sucrose to lipid) demonstrated extended ciprofloxacin release from liposomes (80% released within 7 h) in comparison to the original liquid formulation (80% released within 2 h). In conclusion, a stable and inhalable CNL powder with controlled drug release was successfully prepared by spray drying.

Medication Tracking: Design and Fabrication of a Dry Powder Inhaler with Integrated Acoustic Element by 3D Printing

PURPOSE

Asthma is a prevalent lung disorder that cause heavy burdens globally. Inhalation medicaments can relieve symptoms, improve lung function and, thus, the quality of life. However, it is well-documented that patients often do not get the prescribed dose out of an inhaler and the deposition of drug is suboptimal, due to incorrect handling of the device and wrong inhalation technique. This study aims to design and fabricate an acoustic dry powder inhaler (ADPI) for monitoring inhalation flow and related drug administration in order to evaluate whether the patient receives the complete dose out of the inhaler.

METHODS

The devices were fabricated using 3D printing and the impact of the acoustic element geometry and printing resolution on the acoustic signal was investigated. Commercial Foradil (formoterol fumarate) capsules were used to validate the availability of the ADPI for medication dose tracking. The acoustic signal was analysed with Partial-Least-Squares (PLS) regression.

RESULTS

Indicate that specific acoustic signals could be generated at different air flow rates using a passive acoustic element with specific design features. This acoustic signal could be correlated with the PLS model to the air flow rate. A more distinct sound spectra could be acquired at higher printing resolution. The sound spectra from the ADPI with no capsule, a full capsule and an empty capsule are different which could be used for medication tracking.

CONCLUSIONS

This study shows that it is possible to evaluate the medication quality of inhaled medicaments by monitoring the acoustic signal generated during the inhalation process.

Use of inspiratory profiles from patients with chronic obstructive pulmonary disease (COPD) to investigate drug delivery uniformity and aerodynamic dose emission of indacaterol from a capsule based dry powder inhaler

Most patients using dry powder inhalers (DPIs) are unable to achieve the inhalation parameters recommended for pharmacopoeial in-vitro dose emission testing. The dose emission characteristics of indacaterol Breezhaler (IB) have been measured using COPD patients' inhalation profiles (IPs) when using IB and replayed in-vitro using a breath simulator attached to an Andersen Cascade Impactor. The peak inhalation flow (PIF) of the profiles ranged from 28.3 to 87.8 L/min and inhaled volumes (Vin) from 0.7 to 3 L. The indacaterol total emitted doses (TED), fine particle dose (FPD) and mass median aerodynamic diameter (MMAD) were measured. TED varied between 61% to 83% of the 150 μg nominal dose, the FPD was found to vary between 19% and 30% and the MMAD from 3.7 μm to 2.3 μm with the increase of the profiles' PIF and Vin. The mean (SD) values were 113.4(8.9) μg, 39.7(5.0) μg and 2.7(0.5) μm, respectively. The quantity and the quality of the emitted dose from the indacaterol Breezhaler® are dependent on the capability of a patient generating an optimal inhalation profile. Therefore, when using the IB patients should be encouraged to inhale as fast as they can from the start of their inhalation and for as long as possible.

Ciprofloxacin nanocrystals liposomal powders for controlled drug release via inhalation

This study was conducted to evaluate the feasibility of developing inhalable dry powders of liposomal encapsulated ciprofloxacin nanocrystals (LECN) for controlled drug release. Dry powders of LECN were produced by freeze-thaw followed by spray drying. The formulations contained sucrose as a lyoprotectant in different weight ratios (0.75:1, 1:1 and 2:1 sucrose to lipids), along with 2% magnesium stearate and 5% isoleucine as aerosolization enhancers. The powder physical properties (particle size, morphology, crystallinity, moisture content), in vitro aerosolization performance, drug encapsulation efficiency and in vitro drug release were investigated. The spray dried powders were comprised of spherical particles with a median diameter of ∼1 µm, partially crystalline, with a low water content (∼2% mass) and did not undergo recrystallization at high relative humidity. When dispersed by an Osmohaler® inhaler at 100 L/min, the powders showed a high aerosol performance with a fine particle fraction (% wt. <5 µm) of 66-70%. After reconstitution of the powders in saline, ciprofloxacin nanocrystals were confirmed by cryo-electron microscopy. The drug encapsulation efficiency of the reconstituted liposomes was 71-79% compared with the stock liquid formulation. Of the three formulations, the one containing a sucrose to lipids wt. ratio of 2:1 demonstrated a prolonged release of ciprofloxacin from the liposomes. In conclusion, ciprofloxacin nanocrystal liposomal powders were prepared that were suitable for inhalation aerosol delivery and controlled drug release.

Randomized dose-finding study of batefenterol via dry powder inhaler in patients with COPD

Background

Batefenterol is a novel bifunctional muscarinic antagonist β₂-agonist in development for COPD. The primary objective of this randomized, double-blind, placebo-controlled, active comparator, Phase IIb study was to model the dose–response of batefenterol and select a dose for Phase III development.

Patients and methods

Patients aged ≥40 years with COPD and FEV₁ ≥30% and ≤70% predicted normal were randomized equally to batefenterol 37.5, 75, 150, 300, or 600 µg, placebo, or umeclidinium/vilanterol (UMEC/VI) 62.5/25 µg once daily. The primary and secondary endpoints were weighted-mean FEV₁ over 0–6 hours post-dose and trough FEV₁, analyzed by Bayesian and maximum likelihood estimation E_max of dose–response modeling, respectively, on day 42.

Results

In the intent-to-treat population (N=323), all batefenterol doses demonstrated statistically and clinically significant improvements from baseline vs placebo in the primary and secondary endpoints (191.1–292.8 and 182.2–244.8 mL, respectively), with a relatively flat dose–response. In the subgroup reversible to salbutamol, there were greater differences between batefenterol doses. Lung function improvements with batefenterol ≥150 µg were comparable with those with UMEC/VI. Batefenterol was well tolerated and no new safety signals were observed.

Conclusion

Batefenterol 300 µg may represent the optimal dose for Phase III studies.

SHetA2 Dry Powder Aerosols for Tuberculosis: Formulation, Design, and Optimization Using Quality by Design

Tuberculosis (TB) is a life threatening pulmonary infection caused by Mycobacterium tuberculosis (MTB). Current treatments are complex, lengthy, and associated with severe side effects that decrease patient compliance and increase the probability of the emergence of drug resistant strains. Thus, more effective drugs with little to no side effects are needed to diversify the armamentarium against the global TB epidemic. SHetA2, an anticancer compound with null toxicity at doses much higher than the effective dose, was recently discovered to be active against MTB. In the present study, a dry powder formulation of SHetA2 for pulmonary delivery was developed to overcome its poor aqueous solubility and to maximize its concentration in the lungs, the main site of TB infection. Using quality by design (QbD) methodology, three different formulations of SHetA2 microparticles (MPs) were designed, manufactured, and optimized, SHetA2 alone, SHetA2 PLGA, and SHetA2 mannitol MPs, to maximize the drug dose, target alveolar macrophages, and increase drug solubility, respectively. The resulting three SHetA2 MP formulations had spherical shape with particle size ranging from 1 to 3 μm and a narrow size distribution, suitable for uniform delivery to the alveolar region of the lungs. Upon dispersion with the Aerolizer dry powder inhaler (DPI), all three SHetA2 MP formulations had aerodynamic diameters smaller than 3.3 μm and fine particle fractions (FPF_4.46) greater than 77%. SHetA2 remained chemically stable after MP manufacture by spray drying, but the drug transformed from the crystalline to the amorphous form, which significantly enhanced the solubility of SHetA2. Using a custom-made dissolution apparatus, the FPF_4.46 of SHetA2 MP dissolved much faster and to a greater extent (21.19 ± 4.40%) than the unprocessed drug (3.51 ± 0.9%). Thus, the physicochemical characteristics, in vitro aerosol performance, and dissolution rate of the optimized SHetA2 MPs appear to be suitable to achieve therapeutic concentrations in the lungs.

Performance of dry powder inhalers with single dosed capsules in preschool children and adults using improved upper airway models

The pulmonary administration of pharmaceutical aerosols to patients is affected by age-dependent variations in the anatomy of the upper airways and the inhalation pattern. Considering this aspect, different upper airway models, representing the geometries of adults and preschool children, and a conventional induction port according to the European Pharmacopeia were used for in vitro testing of dry powder inhalers with single dosed capsules (Cyclohaler^®, Handihaler^® and Spinhaler^®). Deposition measurements were performed using steady flow rates of 30 and 60 L/min for the Handihaler^®/Spinhaler^® and 30, 60 and 75 L/min for the Cyclohaler^®. The inhalation volume was set at 1 L. For the Cyclohaler^®, the in vitro testing was supplemented by a pediatric inhalation profile. Slight differences of pulmonary deposition between the idealized adult (11%–15%) and pediatric (9%–11%) upper airway model were observed for the Cyclohaler^®. The applied pediatric inhalation profile resulted in a reduction of pulmonary deposition by 5% compared to steady conditions and indicated the influence of the inhalation pattern on the amount of pulmonary deposited particles. The comparison of two pediatric upper airway models showed no differences. The performance of the Handihaler^® was similar to the Cyclohaler^®. The Spinhaler^® showed an insufficient performance and limited reproducibility in our investigations.

Inspiratory flows and volumes in subjects with cystic fibrosis using a new dry powder inhaler device

Introduction:

Drug inhalation via a dry-powder inhaler (DPI) is a convenient, time efficient alternative to nebulizers in the treatment of cystic fibrosis (CF). Efficient drug administration via DPIs depends on the device resistance and adequate (≥ 45L/min) inspiratory flows and volumes generated by individuals. Dry-powder mannitol is delivered using a RS01 breath-actuated device developed by Plastiape, for Pharmaxis. The study aim was to determine in vivo if CF patients’ inspiratory flows and volumes are adequate to use the RS01 DPI device.

Materials and Methodology:

An open, non-interventional study; enrolled 25 CF subjects, aged ≥ 6 years with FEV1 ≥ 30 to < 90‰ predicted. Inspiratory flows and volumes were measured when subjects inhaled in a controlled manner through the RS01 device in series with a spirometer.

Results:

The mean inspiratory volume (IV) of CF subjects was 1.83L ± 0.97. Their achieved mean ± SD peak inspiratory flow (PIF) was 75.5 ± 27.2L/min. Twenty-three subjects (92%) achieved PIF of > 45L/min with the inhaler device; eighteen of those subjects (78%) had a baseline FEV1 of > 1L.

Conclusion:

Use of the RS01 DPI device allowed adequate inspiratory flow and volume for dispersion of dry-powder mannitol in CF patients.

Inspiratory Flows and Volumes in Subjects with Non-CF Bronchiectasis Using a New Dry Powder Inhaler Device

Introduction:

Drug inhalation via a dry-powder inhaler (DPI) is a convenient, time efficient alternative to nebulizers in the treatment of cystic fibrosis (CF) or non-CF bronchiectasis. Efficient drug administration via DPIs depends on the device resistance and adequate (≥45L/min) inspiratory flows and volumes generated by individuals. Drypowder mannitol is delivered using a RS01 breath-actuated device developed by Plastiape, for Pharmaxis. The study aim was to determine in vivo if non-CF bronchiectasis patients’ inspiratory flows and volumes are adequate to use the RS01 DPI device.

Materials and Methodology:

An open, non-interventional study; enrolled 17 subjects with non-CF bronchiectasis, 18 to 80 years, with baseline FEV1 ≥1.0L and ≥50‰ predicted. Inspiratory flows and volumes were measured when subjects inhaled in a controlled manner through the RS01 device in series with a spirometer.

Results:

The mean inspiratory volume (IV) of non-CF bronchiectasis subjects was 2.08 ± 0.5L and achieved a mean PIF of 78.6 ± 11.2L/min with the inhaler device.

Conclusion:

Use of the RS01 DPI device allowed adequate inspiratory flow and volume for dispersion of dry-powder mannitol in non-CF bronchiectasis patients.

Effect of device design on the aerosolization of a carrier-based dry powder inhaler--a case study on Aerolizer(®) Foradile (®)

The objective of this study is to investigate the effect of device design of the Aerolizer(®) on the aerosolization of a carrier-based dry powder inhaler formulation (Foradile(®)). The Aerolizer was modified by reducing the air inlet size and mouthpiece length to 1/3 of the original dimensions, or by increasing the grid voidage. Aerosolization of the powder formulation was assessed on a multi-stage liquid impinger at air flow rates of 30, 60, and 100 L/min. Coupled CFD-DEM simulations were performed to investigate the air flow pattern and particle impaction. There was no significant difference in the aerosolization behavior between the original and 1/3 mouthpiece length devices. Significant increases in FPF total and FPF emitted were demonstrated when the inlet size was reduced, and the results were explained by the increases in air velocity and turbulence from the CFD analysis. No significant differences were shown in FPF total and FPF emitted when the grid voidage was increased, but more drugs were found to deposit in induction port and to a lesser extent, the mouthpiece. This was supported by the CFD-DEM analysis which showed the particle-device collisions mainly occurred in the inhaler chamber, and the cross-grid design increased the particle-device collisions on both mouthpiece and induction port. The air inlet size and grid structure of the Aerolizer(®) were found to impact significantly on the aerosolization of the carrier-based powder.

Effects of device and formulation on in vitro performance of dry powder inhalers

The study examined the sensitivity of DPI in vitro performance to formulation and device changes. Rotahaler/Rotacaps was selected as the reference DPI drug product, and Aerolizer was selected as the test device. Since the test device was recognized to have much greater efficiency of dispersion, simple modifications to both formulation and device were made in an effort to provide a closer match to the in vitro performance of the reference product. The modifications included varying the drug and lactose particle sizes and/or lactose fine particle content in the test formulations, as well as lowering the specific resistance of the test device. These modifications were intended to address variables important for drug product performance for a defined experimental design and were not intended to mimic the extensive formulation and device design strategies that are employed in an industrial setting. Formulation and device modifications resulted in a modified test product that approached the reference product in the in vitro performance.

A critical view on lactose-based drug formulation and device studies for dry powder inhalation: which are relevant and what interactions to expect?

Many years of research have not led to a profound knowledge of the mechanisms involved in the formulation and dispersion of carrier based mixtures for inhalation. Although it is well understood that the mixing is a key process in DPI carrier based formulation, there remains a limited understanding of how blending processes affect in-process material properties and the resulting distribution of the drug in the final dosage form. A great number of variables are considered relevant to the interfacial forces in adhesive mixtures, but their effects have mostly been investigated individually, without taking account of the influence they may have on each other. Interactions may be expected and without proper choices made and definitions given for all the variables involved, conclusions from studies on adhesive mixtures are of less relevance. By varying any of the variables that are not subject of the study, an opposite effect may be obtained. Currently, there is a strong focus on exploring techniques for the characterisation of drug and carrier surface properties that are believed to have an influence on the interparticulate forces in adhesive mixtures. For a number of surface properties it may be questioned whether they are really the key parameters to investigate however. Their orders of magnitude are subordinate to the effects they are supposed to have on the drug-to-carrier forces. Therefore, they seem rather indicators of other variability and their influence may be dominated by other effects. Finally, the relevance of inhaler design is often ignored. By using powerful inhalers, the effect of many variables of current concern may become less relevant. Carrier properties that are considered disadvantageous at present may even become desirable when a more appropriate type of dispersion force is applied. This can be shown for the effect of carrier surface rugosity when inertial separation forces are applied instead of the more widely applied lift and drag forces. Therefore, inhaler design should be taken into consideration when evaluating studies on adhesive mixtures. It should also become an integral part of powder formulation for inhalation.

Constant size, variable density aerosol particles by ultrasonic spray freeze drying

This work provides a new understanding of critical process parameters involved in the production of inhalation aerosol particles by ultrasonic spray freeze drying to enable precise control over particle size and aerodynamic properties. A series of highly porous mannitol, lysozyme, and bovine serum albumin (BSA) particles were produced, varying only the solute concentration in the liquid feed, c(s), from 1 to 5 wt%. The particle sizes of mannitol, BSA, and lysozyme powders were independent of solute concentration, and depend only on the drop size produced by atomization. Both mannitol and lysozyme formulations showed a linear relationship between the computed Fine Particle Fraction (FPF) and the square root of c(s), which is proportional to the particle density, ρ, given a constant particle size d(g). The FPF decreased with increasing c(s) from 57.0% to 16.6% for mannitol and 44.5% to 17.2% for lysozyme. Due to cohesion, the BSA powder FPF measured by cascade impaction was less than 10% and independent of c(s). Ultrasonic spray freeze drying enables separate control over particle size, d(g), and aerodynamic size, d(a) which has allowed us to make the first experimental demonstration of the widely accepted rule d(a)=d(g)(ρ/ρ(o))(1/2) with particles of constant d(g), but variable density, ρ (ρ(o) is unit density).

Novel dry powder inhaler particle-dispersion systems

Dry powder inhalers are a diverse family of devices that have emerged as a rapidly growing segment of the respiratory therapeutics area. The forces that these devices must impart into dry powder formulations for effective dispersion performance and reproducibility of delivery are relatively large, and multiple mechanisms have been developed in attempts to improve the efficiency of these systems. In this review, we address the reasons for the proliferation of dry powder inhalers, beginning with an abbreviated introduction on the basic inter-particulate forces that need to be disrupted to achieve successful powder dispersion and effective lung delivery. From this background, we survey the diversity of inhaler designs, starting from marketed devices, before introducing some of the novel device designs under development, both patient driven (passive) and device driven (active), as we attempt to link the themes of the device design features to the present understanding of the dynamics governing powder dispersion. Finally, we conclude by providing some assessment on the future of the wide range of device designs and mechanisms that have evolved by considering technical, regulatory and market forces.

Personalizing aerosol medicine: development of delivery systems tailored to the individual

Inhalation of drugs for therapeutic effects is not a recent innovation as illicit drugs have been ‘smoked’ for millennia. Nicotine delivery ‘devices’ in convenient packaged cartons of cigarettes are simple to use, inexpensive per dose and accessible to people of most ages and lung function, but of course their use leads to increased cancer, emphysema, heart disease and other medical and societal problems. In contrast, many inhalation pharmaceutical medical devices are expensive, nonportable, inconvenient, and/or are used improperly thus leading to poor therapeutic benefit. We review the current state of the art with respect to aerosol delivery, inhalation devices and the ability to personalize the treatment and management of lung disease. The confluence of many drivers will lead to more programmable and flexible devices in the future: the transition from the blockbuster model to customized therapy, technological advancements (e.g., smartphones) and cultural changes including social networking.

Characterisation and aerosolisation of mannitol particles produced via confined liquid impinging jets

Mannitol particles, produced by spray drying (SD), have been used commercially (Aridol) in bronchial provocation test. In this study, we propose an alternative method to produce inhalable mannitol powders. The elongated mannitol particles (number median length 4.0microm, and axial ratio of 3.5) were prepared using a confined liquid impinging jets (CLIJs) followed by jet milling (JM). Spray dried and jet milled raw mannitol particles were compared in an attempt to assess the performance of the particles produced by the new method. Aerosol performance of the three different powders (CLIJ, SD, and JM) was relatively poor (fine particle fraction or FPF(loaded) below 15%) when dispersed by the Rotahaler. Dispersion through the Aeroliser led to better aerosol performance of the CLIJ mannitol (FPF(loaded) 20.3%), which is worse than the JM (FPF(loaded) 30.3%) and SD mannitol particles (FPF(loaded) 45.7%) at 60 L/min, but comparable (FPF(loaded) 40.0%) with those of the JM (FPF(loaded) 40.7%) and SD (FPF(loaded) 45.5%) powders at 100L/min. Hence, the optimum use of these elongated mannitol particles can be achieved at increased air flow with a more efficient inhaler. In addition to crystallinity, morphology, and particle size distribution, the surface energies of these powders were measured to explain the differences in aerosol performance. A major advantage of using the CLIJ method is that it can be scaled up with a good yield as the precipitate can be largely collected and recovered on a filter, compared with spray drying which has a low collection efficiency for fine particles below 2microm.

Formoterol dry-powder inhaler for the treatment of asthma and chronic obstructive pulmonary disease

Formoterol, a long-acting beta2-adrenergic agonist, is used as an inhaled bronchodilator therapy for patients with asthma or for the prevention of exercise-induced bronchospasm in children and in chronic obstructive pulmonary disease. Formoterol has unique characteristics of rapid onset and sustained duration of action compared with other bronchodilators. In addition to its effectiveness as regular maintenance therapy in asthma and chronic obstructive pulmonary disease, formoterol is also reported to be effective as an as-needed reliever therapy in patients with asthma. Formoterol is available in several different types of dry-powder inhalers and pressurized metered-dose inhalers.

Inhalation devices for long-acting beta2-agonists: efficiency and ease of use of dry powder formoterol inhalers for use by patients with asthma and COPD

BACKGROUND

Since the long-acting beta(2)-agonist bronchodilator, formoterol, first became available for the treatment of subjects with asthma or chronic obstructive pulmonary disease (COPD), generic forms of this agent have been launched in a variety of devices. It is timely to review the characteristics of the original dry powder delivery device, the single-dose Aerolizer, its in vitro performance and its comparability with other inhaler devices that are now available for delivery of formoterol.

SCOPE

This review focuses on the performance of the formoterol Aerolizer inhaler in comparison with other inhalers. Publically available data (PubMed) on the device performance characteristics of the Aerolizer were reviewed and summarized, together with the results of comparative studies performed by the authors. Published studies (PubMed) on patient handling and inhaler technique that include the Aerolizer are described and studies comparing the clinical effect of formoterol in the Aerolizer with formoterol delivered via other devices were reviewed and are summarized.

FINDINGS

The Aerolizer performs consistently in dosing efficiency across a range of inspiratory flow rates, suggesting its suitability for use by patients with differing inspiratory flow abilities. The single-dose, capsule-based nature of the device provides patients with obvious feedback on whether the drug has been taken successfully and the Aerolizer has been shown to be one of the more easily used devices in comparative patient handling studies. Studies comparing the clinical effect of formoterol delivered by different inhalation devices show that formoterol via Aerolizer has an equivalent therapeutic effect.

CONCLUSION

Judged on the basis of dosing efficiency, ease of use and clinical equivalence, formoterol Aerolizer remains a useful option in the management of patients with asthma or COPD.

Promising ternary dry powder inhaler formulations of cromolyn sodium: formulation and in vitro-in vivo evaluation

Glucose monohydrate and sorbitol were evaluated as alternative carriers to á-lactose monohydrate in dry powder inhalations. Cromolyn sodium (CS) - carrier binary formulae were prepared and tested in vitro by aerosolization via a twin stage impinger using three types of inhaler devices; Spinhaler, Aerolizer and Handihaler. Glucose monohydrate and sorbitol-containing formulae that were inhaled via a Handihaler showed significantly higher drug fine particle fractions (P<0.001) than that of the same formulae aerosolized via other devices. Upon storage of the prepared formulae under uncontrolled humidity, that may be encountered during storage and use, marked reductions in these fractions were observed. Incorporation of an optimum Aerosil 200 concentration, as a ternary component, minimized this effect. A urinary excretion pharmacokinetic method was used to evaluate the bioavailability of the selected ternary formulae, inhaled via a Handihaler, relative to the marketed Intal Spincaps, inhaled via a Spinhaler. It was found that the relative bioavailability percentages of the developed formulae were more than twice that of the marketed one suggesting possible future utilization of these more effective ternrry formulae using the more efficient Handihaler inhaler device.

In Vitro Comparison of Two Delivery Devices for Administering Formoterol: Foradil® P and Formoterol Ratiopharm Single-Dose Capsule Inhaler

Formoterol, a long-acting beta (2)-agonist with a rapid onset of bronchodilation, is available in various delivery devices. However, differences in the size and uniformity of drug particles generated by different devices may result in variable clinical effects. The present study compared in vitro the aerodynamic particle size distribution, emitted dose and device resistance of formoterol delivered via Foradil Aerolizer (Foradil P) with those a non-proprietary single-dose capsule inhaler (ratiopharm), using an 8-stage Andersen Cascade Impactor set at a flow of 60 L/min. Relative to the formoterol ratiopharm capsule inhaler, Foradil Aerolizer produced particles with a smaller mass median aerodynamic diameter (3.5 vs. 4.1 microm, p = 0.018) and a smaller measured particle diameter distribution (geometric standard deviation 2.2 vs. 2.5, p = 0.048). The Foradil Aerolizer produced a 44% higher fine particle dose than the single-dose capsule inhaler (2.6 vs. 1.8 microg, p = 0.0001). Although the single-dose capsule inhaler produced a higher total emitted dose than that from Foradil Aerolizer (11.2 vs. 10.0 microg, p = 0.155, not significant), the respirable fraction from Foradil Aerolizer was 58% higher (25.7 vs. 16.3%, p = 2 x 10(8)). Both devices had a similarly low airflow resistance. These relative particle size profiles suggest that the Aerolizer may provide a more clinically effective delivery of formoterol to the lungs at the high inspiratory flows such as are typically achieved using this device.

An update on chronic obstructive pulmonary disease

OBJECTIVE

Provide an update on the diagnosis and management of chronic obstructive pulmonary disease (COPD) based on new international and national guidelines. COPD affects approximately 5% to 7% of adults in the United States, with a higher prevalence in elderly persons (10% in elderly males).

DATA SOURCE

A Medline search of relevant articles and the Global Initiative for Obstructive Lung Disease and the American Thoracic Society/European Respiratory Society COPD Guidelines.

STUDY SELECTION

Articles and current guidelines relevant to pharmacists working with COPD patients in extended-care facilities.

DATA SYNTHESIS

COPD is a chronically progressive disease that ultimately leads to major health impairment. New international and national guidelines recently have become available; these guidelines provide extensive insight into many aspects of the disease. Key interventions include early diagnosis, use of pulmonary-function testing, smoking cessation, supplemental oxygen, pulmonary rehabilitation, optimization of pharmacological therapies, and preventing--as well as minimizing--the impact of acute exacerbations of COPD. Optimizing the use of bronchodilators and, in selected patients, the use of corticosteroids are especially important pharmacological interventions in the management of COPD. Patients are started on short-acting bronchodilators; long-acting agents can be added and, in some patients, inhaled corticosteroids can be added as well. Other pharmacological interventions include smoking cessation therapies and the use of anti-infective and mucolytics/expectorants.

CONCLUSION

Pharmacists can assist in proper drug selection and administration in COPD patients in long-term care facilities. In addition, they can assist in preventing complications of drug therapy such as steroid-induced osteoporosis.

Do all dry powder inhalers show the same pharmaceutical performance?

Important measures of pharmaceutical performance of dry powder inhalers include total emitted dose (TED, the quantity of drug emitted from the device when used at a fixed flow rate, typically 60 l/min or the flow rate achieved at a pressure drop of 4 kPa) and fine particle mass (FPM, the quantity of drug with small particles, typically with an aerodynamic diameter of less than 5 microns emitted from the device at a fixed flow rate). There is a wide range of dry powder inhalers available. The complexity of design decisions means that dry powder inhalers are very diverse, with identical designs unlikely. It is not surprising therefore that evidence from in vitro studies shows considerable variation in pharmaceutical performance of dry powder inhalers. Although neither TED nor FPM can accurately predict in vivo performance, it may be expected that highly variable or inhalation flow sensitive in vitro behaviour will be reflected in variable performance when used by patients.

Influence of air flow on the performance of a dry powder inhaler using computational and experimental analyses

PURPOSE

The aims of the study are to analyze the influence of air flow on the overall performance of a dry powder inhaler (Aerolizer and to provide an initial quantification of the flow turbulence levels and particle impaction velocities that maximized the inhaler dispersion performance.

METHODS

Computational fluid dynamics (CFD) analysis of the flow field in the Aerolizer, in conjunction with experimental dispersions of mannitol powder using a multistage liquid impinger, was used to determine how the inhaler dispersion performance varied as the device flow rate was increased.

RESULTS

Both the powder dispersion and throat deposition were increased with air flow. The capsule retention was decreased with flow, whereas the device retention first increased then decreased with flow. The optimal inhaler performance was found at 65 l min(-1) showing a high fine particle fraction (FPF) of 63 wt.% with low throat deposition (9.0 wt.%) and capsule retention (4.3 wt.%). Computational fluid dynamics analysis showed that at the critical flow rate of 65 l min(-1), the volume-averaged integral scale strain rate (ISSR) was 5,400 s(-1), and the average particle impaction velocities were 12.7 and 19.0 m s(-1) at the inhaler base and grid, respectively. Correlations between the device flow rate and (a) the amount of throat deposition and (b) the capsule emptying times were also developed.

CONCLUSIONS

The use of CFD has provided further insight into the effect of air flow on the performance of the Aerolizer. The approach of using CFD coupled with powder dispersion is readily applicable to other dry powder inhalers (DPIs) to help better understand their performance optimization.

Formoterol delivered via a new multi-dose dry powder inhaler (Certihaler) is as effective and well tolerated as the formoterol dry powder inhaler (Aerolizer) in children with persistent asthma

The Certihaler is a new multi-dose dry powder inhaler for the delivery of formoterol (Foradil), a long-acting beta(2)-agonist. This dose-ranging study compared the efficacy and safety of formoterol 5, 10, 15 and 30 microg and placebo administered via the Certihaler or formoterol 12 microg via a single-dose dry powder inhaler (Aerolizer) in children with persistent asthma. This was a randomized, placebo-controlled, double-blind, double-dummy, incomplete block crossover, dose-finding and pharmacokinetic study. Children (5-12 years, n = 77) received four of the active treatments twice weekly (BID) for 1 week separated by 1-week single-blind washouts. The primary efficacy variable was 12-h AUC of FEV(1) after 1 week's treatment. Secondary variables included serial 12-h FEV(1). A subset of patients (n = 37) participated in a pharmacokinetic analysis. All formoterol doses resulted in significant increases in 12-h AUC of FEV(1) compared with placebo, and there was no difference between active treatments. The onset of action of formoterol was <3 min for all active treatments. Doses of formoterol > or =10 microg via the Certihaler increased FEV(1) significantly for up to 12 h compared with placebo. The 5 microcg dose via the Certihaler and 12 microg dose via the Aerolizer had a significant effect up to 8 and 7 h post-dose, respectively. Urinary excretion of formoterol via the Certihaler increased in a dose-proportional manner. All formoterol doses were well tolerated, but some patients experienced tremor at the 15 and 30 microg doses. Despite the lack of significant differences between the active doses in the overall bronchodilation, formoterol 10 microg BID via the Certihaler was the dose that provided the best balance between efficacy and tolerability: its duration of action was sustained over 12 h, contrary to that the lower dose (5 microg BID), whereas its tolerability, especially with regard to tremor, was better than the higher doses (15 and 30 microg BID). Overall, Certihaler 10 microg BID was not significantly different from formoterol 12 microg BID via Aerolizer.

The ideal inhaler: design and characteristics to improve outcomes

Inhalation therapy is Likely to continue to dominate asthma treatment. The pressurised metered dose inhaler (pMDI) accounts for most of the inhaler market world-wide, but is inefficient and difficult to use. Dry powder inhalers (DPIs) have several advantages over MDIs. They are breath-activated, easy and convenient to use and environmentally friendly. The Turbuhaler is the most widely used DPI, offering good deposition with sufficient inspiratory flow, but it provides no confirmation of dosing, exhibits high dose variation, has a high intrinsic resistance, and inspiratory flow profile-dependent drug deposition. The Novolizer (VIATRIS, Frankfurt, Germany) is a new DPI which has several characteristics of an 'ideal' inhaler. It is convenient and easy to use, demonstrate and teach, provides accurate and consistent drug delivery and provides patients with feedback of dose taken. The Novolizer is a promising new delivery system for inhalation therapy.

Inspiratory flow rates and volumes with the Aerolizer dry powder inhaler in asthmatic children and adults

OBJECTIVE

To assess the peak inspiratory flow rate (PIFR) and forced inspiratory vital capacity (FIVC) through the formoterol (Foradil*) Aerolizer* in patients with mild, moderate and severe asthma.

RESEARCH DESIGN AND METHODS

PIFR and FIVC were assessed in 33 adults and 32 children using a spirometer alone (baseline), a spirometer with an adaptor, and a spirometer with an adaptor and the Aerolizer inhaler (placebo loaded).

RESULTS

Of adult patients using the Aerolizer inhaler, 73% had PIFR values of >100 l/min and 91% had values of >60 l/min. PIFR in adults was reduced from a mean baseline of 283 l/min to 118 l/min through the loaded Aerolizer inhaler. Similarly, 75% of children using the Aerolizer inhaler had PIFR values >80 l/min and 91% had values of > 60 l/min. The mean PIFR in children was reduced from a baseline of 154 l/min to 100 l/min through the loaded Aerolizer inhaler. Only small mean decreases from baseline were observed in FIVC through the loaded Aerolizer inhaler: 8.4% in adults and 3.8% in children. FIVC values of > 2.0 litre were achieved in 82% of adults, and 81% of children achieved FIVC values of >1.5 litre.

CONCLUSIONS

This study, albeit in a relatively small patient population, suggests that most children and adults with asthma can generate PIFRs of > 60 l/min and FIVCs of > 1.5 litre through the Aerolizer inhaler regardless of their disease severity. Such findings compare extremely favourably with other dry powder inhalers.

Bronchodilating effects of cumulative doses of formoterol from a novel multi-dose inhaler (Airmax)

The bronchodilating properties of formoterol from a novel multi-dose inhaler, Airmax 6 microg and from a single-dose dry powder inhaler Foradil Aeroliser 12 microg were investigated in 31 adult asthmatics with FEV1 > or = 60% predicted and a reversibility > or = 12%. Patients received on a single day four doses of formoterol: cumulative dose 6, 12, 24 and 48 microg from Airmax, or 12, 24, 48 and 96 microg from Aeroliser. The mean FEV1 (SD) from baseline to 1 h after the final cumulative dose increased by 0.81 l from 2.62 (0.58) to 3.43 l (0.70) with Airmax and by 0.85 l from 2.65 (0.60) to 3.5 l (0.68) with Aeroliser. All 90% CIs for all four dose comparisons were within the equivalence range +/- 0.11. There was a higher incidence of hypokalaemia and hyperglycaemia at highest doses during treatment with the Aeroliser than with Airmax. In conclusion, formoterol delivered from Airmax provides a dose-dependent bronchodilating effect which is similar to that obtained by Aeroliser, at double the dose.