Scintigraphic assessment of drug delivery from the Ultrahaler dry powder inhaler

Budesonide associated with exogenous pulmonary surfactant in a novel formulation to improve the delivery to the lung

Lung delivery for glucocorticoids (GCs) is very low and depends on the system used. Exogenous pulmonary surfactant (EPS) is a promising tool to transporting GCs efficiently to the airways. We developed a new formulation of EPS with Budesonide (BUD) incorporated into EPS membranes (EPS-BUD) to improve lung delivery of BUD. We evaluated the biodistribution and pharmacokinetic of the transported BUD by intra-tracheal instillation of EPS-BUD in healthy rats. Aqueous suspension of Budesonide was used as control. Budesonide and its esters present in trachea, kidneys and lungs were determined by HPLC. The delivery of BUD in lung for EPS-BUD group was 75 % of total instilled and only 35 % for the control group. BUD was rapidly internalized in pneumocytes and a high proportion of Budesonide esters and persistent concentrations of active free BUD were found for up to 6 h after instillation. The new EPS-BUD formulation developed significantly improves the deposition and increases the permanence of BUD in lung.

On the Validation of Generational Lung Deposition Computer Models Using Planar Scintigraphic Images: The Case of Mimetikos Preludium

Background: Mechanistic computer models for calculation of total and regional deposition of aerosols in the lungs are important tools for predicting or understanding clinical studies and for facilitating development of pharmaceutical inhalation products. Validation of such models must be indirect since generational in vivo data are lacking. Planar scintigraphy is probably the most common method addressing regional lung deposition in humans. Scintigraphic regions of interest (ROI) contain mixtures of airway generations and can therefore not be directly compared to model results. We propose a method to translate computed deposition per generation to deposition in scintigraphic ROI to be able to compare computed results with corresponding results obtained in humans. Methods: The total and regional lung deposition computed by the one-dimensional algebraic typical-path software Mimetikos Preludium was compared for 18 study legs in 14 published deposition studies involving 9 dry powder inhaler brands to the activity in planar scintigraphic ROIs (oropharyngeal, central [C], intermediate, and peripheral [P]) using for the computed regional lung distribution a generic mapping of the contribution of each airway generation to the ROIs. Results: The computed oropharyngeal and total lung deposition correlated with high significance (p < 0.0001) to the scintigraphic results with a near one-to-one relationship. For the regional lung distribution, computed C, P, and P/C results correlated with high significance (p < 0.01) to the corresponding scintigraphic measures. The computed C (P) deposition was on average about 28% lower (8% higher) than the mean scintigraphic results. The computed P/C ratio was on average 29% higher than the mean scintigraphic ratio. Conclusions: The results indicate that both the computational deposition model and the mapping algorithm are valid. The small underprediction of the C region merits further investigations. We believe that this method may prove useful also for the validation of computational fluid particle dynamic lung deposition models.

The Confusing World of Dry Powder Inhalers: It Is All About Inspiratory Pressures, Not Inspiratory Flow Rates

Dry powder inhalers (DPIs) all have the ability to aerosolize dry powders, but they each offer different operating mechanisms and resistances to inhaled airflow. This variety has resulted in both clinician and patient confusion concerning DPI performance, use, and effectiveness. Particularly, there is a growing misconception that a single peak inspiratory flow rate (PIFR) can determine a patient's ability to use a DPI effectively, regardless of its design or airflow resistance. For this review article, we have sifted through the relevant literature concerning DPIs, inspiratory pressures, and inspiratory flow rates to provide a comprehensive and concise discussion and recommendations for DPI use. We ultimately clarify that the controlling parameter for DPI performance is not the PIFR but the negative pressure generated by the patient's inspiratory effort. A pressure drop ∼≥1 kPa (∼10 cm H2O) with any DPI is a reasonable threshold above which a patient should receive an adequate lung dose. Overall, we explore the underlying factors controlling inspiratory pressures, flow rates and dispensing, and dispersion characteristics of the various DPIs to clarify that inspiratory pressures, not flow rates, limit and control a patient's ability to generate sufficient flow for effective DPI use.

Lung Deposition of the Dry Powder Fixed Combination Beclometasone Dipropionate Plus Formoterol Fumarate Using NEXThaler® Device in Healthy Subjects, Asthmatic Patients, and COPD Patients

Background: This study evaluated the lung deposition and the distribution pattern in the airways of a fixed combination of beclometasone dipropionate (BDP) and formoterol fumarate (FF) (100/6 μg) delivered as an extrafine dry powder formulation (mass median aerodynamic diameter, MMAD (μm) BDP = 1.5; FF = 1.4) through the NEXThaler^® device in healthy subjects, asthmatics, and patients with COPD.

Methods: Healthy subjects (n = 10), asthmatic patients (n = 9; 30%≤FEV₁ < 80%), and COPD patients (n = 9; FEV₁/FVC ≤70%, 30%≤FEV₁ < 50%) completed this open-label, single administration (inhalation of four actuations) parallel group study. After inhalation of ^99mTc-radiolabeled BDP/FF combination (radiolabeled BDP + unlabeled FF), the drug deposition was assessed using a gamma-scintigraphy technique. Patients' lung function was assessed.

Results: No significant difference in drug deposition was observed between the three study groups. Mean lung deposition, extrathoracic deposition, and amount exhaled ranged, respectively, between 54.9% and 56.2%, between 41.8% and 43.2%, and between 1.6% and 3.3% of BDP emitted dose (71.7 ± 2.5 μg) for the three study groups. The central to peripheral ratio (reflecting the lung distribution pattern) ranged between 1.23 and 2.02 for the three study groups, indicating a distribution of the drug throughout the airways, including periphery. The study treatment produced a forced expiratory volume in one second (FEV₁) increase over time, reaching a maximum improvement generally within 1–4 hours.

Conclusions: The fixed extrafine dry powder combination BDP/FF (100/6 μg) administered through the DPI NEXThaler^® achieved similar intrapulmonary deposition in healthy subjects, in asthmatic patients, and COPD patients (approximately 55% of emitted dose) irrespective of the underlying lung disease with a negligible amount of exhaled particles. The study showed high reliability of the device, reproducible dosing, and distribution throughout the lungs. The results supported the concept of efficient delivery of the combination to the target pulmonary regions, thanks to the extrafine formulation. FEV₁ profile confirmed a relevant pharmacodynamic effect of the product.

The Impact of Inspiratory Flow Rate on Drug Delivery to the Lungs with Dry Powder Inhalers

Current marketed dry powder inhalers utilize the energy from patient inspiration to fluidize and disperse bulk powder agglomerates into respirable particles. Variations in patient inspiratory flow profiles can lead to marked differences in total lung dose (TLD), and ultimately patient outcomes for an inhaled therapeutic. The present review aims to quantitate the flow rate dependence in TLD observed for a number of drug/device combinations using a new metric termed the Q index. With this data in hand, the review explores key attributes in the design of the formulation and device that impact flow rate dependence. The review also proposes alternative in vitro methods to assess flow rate dependence that more closely align with in vivo observations. Finally, the impact of variations in flow rate on lung function for inhaled bronchodilators is summarized.

Asthma medication delivery: mists and myths

Asthma is usually treated with inhaled corticosteroids (ICS) and bronchodilators generated from pressurized metered dose inhalers (pMDI), dry powder inhalers (DPI), or nebulizers. The target areas for ICS and beta 2-agonists in the treatment of asthma are explained. Drug deposition not only depends on particle size, but also on inhalation manoeuvre. Myths regarding inhalation treatments lead to less than optimal use of these delivery systems. We discuss the origin of many of these myths and provide the background and evidence for rejecting them.

Deposition, imaging, and clearance: what remains to be done?

Deposition and clearance studies are used during product development and in fundamental research. These studies mostly involve radionuclide imaging, but pharmacokinetic methods are also used to assess the amount of drug absorbed through the lungs, which is closely related to lung deposition. Radionuclide imaging may be two-dimensional (gamma scintigraphy or planar imaging), or three-dimensional (single photon emission computed tomography and positron emission tomography). In October 2009, a group of scientists met at the "Thousand Years of Pharmaceutical Aerosols" conference in Reykjavik, Iceland, to discuss future research in key areas of pulmonary drug delivery. This article reports the session on "Deposition, imaging and clearance." The objective was partly to review our current understanding, but more importantly to assess "what remains to be done?" A need to standardize methodology and provide a regulatory framework by which data from radionuclide imaging methods could be compared between centers and used in the drug approval process was recognized. There is also a requirement for novel radiolabeling methods that are more representative of production processes for dry powder inhalers and pressurized metered dose inhalers. A need was identified for studies to aid our understanding of the relationship between clinical effects and regional deposition patterns of inhaled drugs. A robust methodology to assess clearance from small conducting airways should be developed, as a potential biomarker for therapies in cystic fibrosis and other diseases. The mechanisms by which inhaled nanoparticles are removed from the lungs, and the factors on which their removal depends, require further investigation. Last, and by no means least, we need a better understanding of patient-related factors, including how to reduce the variability in pulmonary drug delivery, in order to improve the precision of deposition and clearance measurements.

Advancements in dry powder delivery to the lung

The dry powder inhaler (DPI) has become widely known as a very attractive platform for drug delivery. Many patients have traditionally used DPIs to treat asthma and chronic obstructive pulmonary disease. Recently, the development of new DPIs for delivering therapeutic proteins such as insulin has been accelerated by patient demands, and innovative research. The current market for DPIs has over 20 devices presently in use, and many devices under development for delivering a variety of therapeutic agents. DPIs are recognized as suitable alternatives to pressurized metered dose inhalers for some patients, but the performance of DPI devices may vary according to a given patient's physiological condition. This variation can be associated with the necessary powder dispersion mechanism of each device. As such, much interest has focused on the development of efficient powder dispersion mechanisms, as this effectively minimizes the influence of interpatient variability. This article reviews DPI devices currently available, advantages of newly developed devices, outlines some requirements for future device design.

Development of a dry powder inhaler, the Ultrahaler, containing triamcinolone acetonide using in vitro-in vivo relationships

Triamcinolone acetonide (TAA) is safe and effective corticosteroid that is marketed as an MDI (metered dose inhaler) (Azmacort) for the treatment of asthma. A novel dry powder inhaler (DPI), the Ultrahaler, has been developed to deliver Azmacort as another alternative to provide non-CFC formulation for the asthmatic patients. The Ultrahaler is breath actuated and, unlike MDI, does not require coordination of inhalation with the actuation of the device. However, with the Ultrahaler device, like any dry powder inhalation device, the challenge was the on-target and uniform delivery of the drug at the site of action (lungs) with different dose strengths. Due to the complexities of oral inhaled formulations and the topical nature of drug delivery to the lung for efficacy, the reformulation requires careful consideration and support throughout their development, using a combination of in vitro and in vivo studies. This paper describes in vitro studies and two clinical pharmacokinetic studies conducted in a sequence that helped to establish optimum doses for the Ultrahaler. In vitro data were used to guide the initial selection of doses that were then compared in vivo using a pharmacokinetic study with a charcoal block. The in vitro tests included quantifying the target-delivered dose, dose uniformity throughout the life of the device, and the particle size distribution. Particle size distribution was measured using multistage liquid impinger (MSLI) or the Andersen Cascade Impactor (ACI). For in vitro testing, TAA was measured by HPLC methods. Based on the preliminary in vitro data for the respirable fraction, dose strengths with an MDI and the Ultrahaler for the first study were determined. The in vivo assessment consisted of a four-way crossover study following oral inhalation using both MDI (75 and 225 microg/actuation, reference treatment) and comparable respirable doses in the DPI (130 and 360 microg/actuation) devices in healthy volunteers in the presence (lung deposition) and absence (lung and oropharynx deposition) of the charcoal block. Plasma TAA concentrations were determined using a radioimmunoassay (RIA) method. The in vitro data also showed dose proportionality with DPI formulation, and the doses delivered were within 13% of the target doses. A measure of dose uniformity, the relative standard deviation (%RSD) of dose, was less than 15%. Plasma TAA exposure of DPI formulations was compared with that of MDI formulations. Mean ratios (DPI/MDI) of the AUCinf were close to unity for the lower dose strength. However, for the higher dose strength, plasma exposure was higher with the Ultrahaler formulation as compared with the MDI formulation (mean AUCinf DPI/MDI ratios: 1.96). These differences seem to be due to less than proportional increases in the MDI formulation. Based on these results and using the higher dose strength of the MDI as the comparator, the new dose strengths of the Ultrahaler were chosen, ie, 100, 225, and 450 mug/actuation. Plasma TAA concentrations were measured by LC/MS/MS methods. The mean TAA concentrations and AUCinf and Cmax values increased in a dose-proportional manner with an increase in dose for the DPI formulation. The pharmacokinetic parameters showed low variability (10%-33%). Fine particle mass (in vitro testing) and TAA exposure in plasma following DPI administration were compared. Fine particle performance in vitro related well with in vivo pharmacokinetic performance (R=AUCinf-0.9998, Cmax-0.9956). In conclusion, in vitro and in vivo data were in agreement and good control over the target-dose delivery and dose proportionality could be achieved in the early stages of the development of the Ultrahaler device and were critical in guiding and ensuring the success of the reformulation efforts for Azmacort.

Dry powder inhalers for pulmonary drug delivery

The pulmonary route is an interesting route for drug administration, both for effective local therapy (asthma, chronic obstructive pulmonary disease or cystic fibrosis) and for the systemic administration of drugs (e.g., peptides and proteins). Well-designed dry powder inhalers are highly efficient systems for pulmonary drug delivery. However, they are also complicated systems, the the performance of which relies on many aspects, including the design of the inhaler (e.g., resistance to air flow and the used de-agglomeration principle to generate the inhalation aerosol), the powder formulation and the air flow generated by the patient. The technical background of these aspects, and how they may be tuned in order to obtain desired performance profiles, is reviewed. In light of the technical background, new developments and possibilities for further improvements are discussed.

SCF-Engineered Powders for Delivery of Budesonide from Passive DPI Devices

The objective of this study was to develop SEDS-engineered budesonide particles suitable for dry powder inhalation delivery and to evaluate their aerosol performance across a range of passive dry powder inhalers (DPI). SEDS budesonide powders were manufactured in Nektar's SCF manufacturing plant and compared to the micronized drug and commercial powder (Pulmicort Turbuhaler, AstraZeneca). Aerosol performance was evaluated by determining emitted dose (ED) by a variation of the USP method and fine particle fraction (FPF) using Andersen cascade impaction. The SCF powder dispersed best in the Turbospin and Eclipse devices, exhibiting high EDs (70%-80%) and relatively low variability (RSD 8%-13%). Regardless of the device, the SEDS material outperformed both the micronized drug and the commercial powder, while exhibiting good batch-to-batch reproducibility (RSD <5%). All powders exhibited flow rate-dependent ED, albeit for the SEDS material it was minimized at reduced fill weights. This was attributed to inadequate and variable powder clearance from the capsules at low inspiratory flow rates, which was more pronounced in the Eclipse and Cyclohaler. The results demonstrate that SEDS is an attractive particle-engineering process that may enhance pulmonary performance of budesonide and possibly facilitate development of other small molecule pulmonary products in passive DPI.

Pharmacoscintigraphic Comparison of HMR 1031, a VLA-4 Antagonist, in Healthy Volunteers Following Delivery Via a Nebulizer and a Dry Powder Inhaler

A pharmacoscintigraphic study was conducted to compare the dose deposition of HMR 1031 from the existing nebulizer formulation and the new Ultrahaler device to help determine the doses for future phase 2 trials. This was a single-dose, open-label, randomized, two-way crossover study in which HMR 1031 (3 mg) was delivered by the Ultrahaler and the Pari LC Star nebulizer to 12 healthy male subjects. For both treatments, the formulations were radiolabeled with technetium-99m pertechnetate such that a maximum of 10 MBq was delivered on each study day. Scintigraphic images were acquired immediately after dosing to estimate the percentage of the dose delivered to the lungs and oropharynx. Serial plasma samples were collected up to 12 hours post-dose on each occasion and analyzed for HMR 1031 by a LC/MS/MS method with a lower limit of quantitation of 10 pg/mL (0.01 ng/mL). Pharmacokinetic parameters were calculated for HMR 1031 using noncompartmental methods. No serious adverse events were reported. The systemic absorption of HMR 1031 following inhalation administration was relatively rapid, with median T(max) values of 0.5 hours and 1.0 hours post-dose after administration via Ultrahaler and nebulizer, respectively. The mean plasma AUC(0-12) (Ultrahaler, 15.8 ng*h/mL; nebulizer, 11.1 ng*h/mL) and C(max) (Ultrahaler, 4.96 ng/mL; nebulizer, 2.28 ng/mL) values were approximately 42% and 118% higher for the Ultrahaler compared with the nebulizer. The mean terminal half-life of HMR 1031 was similar after administration from both devices (2.91 and 3.18 hours). Based on the scintigraphic data, the lung deposition of HMR 1031 after administration by Ultrahaler (24.6% of the administered dose) was approximately 37% higher compared with the lung deposition from the nebulizer (18.0% of the administered dose). This observation was in agreement with the relative difference in the plasma AUC values achieved after administration of the two formulations. The in vivo results based on the scintigraphic data were also comparable with those from in vitro studies for the Ultrahaler. Based on the ratio of the dose delivered by both the formulations, the required doses for the future Ultrahaler formulation can be predicted.

The influence of inhaler selection on efficacy of asthma therapies

Many different devices are available to aid inhalational drug delivery. Although each device is claimed to have advantages over its rivals, the evidence to support greater efficacy of a particular device is scanty. Most comparative studies are underpowered or flawed in their design. They may use inappropriate end-points, or involve healthy subjects, whose response may be very different from the patient with acute severe asthma. The dosage of drug used in a trial may be at the shallow part of the dose-response curve, masking differences in devices. Only in a few cases have clinical trials detected a significant difference between devices, and trials have rarely taken patient preference into account. The most efficacious device in practice is likely to be the one that the patient will use regularly and in accordance with a health care workers' recommendations.

Deposition and pharmacokinetics of budesonide from the Miat Monodose inhaler, a simple dry powder device

Dry powder inhalers (DPIs) are used to deliver asthma drugs to patients, but lung deposition may depend upon the degree of inspiratory effort. The pulmonary deposition of the glucocorticosteroid budesonide (SMB-Galephar) has been assessed in 12 asthmatic patients when delivered by the Monodose inhaler (Miat, Milan, Italy); the Pulmicort Turbuhaler DPI (AstraZeneca, Lund, Sweden) was used as a comparator product. Patients inhaled from each device with maximal or sub-maximal inspiratory effort: Monodose inhaler 90 vs 45 l/min; Turbuhaler DPI 60 vs 30 l/min. The formulations were radiolabelled with (99m)Tc, and deposition of budesonide was quantified by gamma scintigraphy. Mean (SD) whole lung deposition for the Monodose inhaler (% capsule dose), was independent of inspiratory effort (maximal: 21.4 (4.3)%; sub-maximal: 21.4 (7.5)%), while lung deposition for the Turbuhaler DPI (% metered dose) fell significantly with decreasing inspiratory effort (maximal: 25.1 (6.1)%; sub-maximal: 18.5 (6.5)%; P<0.05). The plasma concentrations of budesonide showed the same trends as the whole lung deposition data. The Monodose inhaler showed inspiratory effort-independent drug delivery characteristics, and could prove be a valuable low-cost alternative to more complex devices such as the Turbuhaler DPI. The Monodose inhaler may be especially useful in groups of patients unable to inhale maximally through DPIs, including young children and adult patients with severe respiratory impairment.

Lung deposition of salbutamol in healthy human subjects from the MAGhaler dry powder inhaler

The MAGhaler (Mundipharma GmbH) is a multidose dry powder inhaler (DPI) containing a novel formulation of drug and lactose compacted by an isostatic pressing technique (GGU GmbH). On actuation, a precise dose is metered from a compacted ring-shaped drug tablet. In this study, the lung deposition of salbutamol from this device has been assessed. Ten healthy non-smoking subjects completed a two-way cross-over study assessing the pulmonary deposition of salbutamol (200 microg) from the MAGhaler at high (60 l/min) and low (30 l/min) peak inhaled flow rates (PIFRs), representing maximal and sub-maximal inspiratory efforts. The formulation was radiolabelled with 99mTc, and lung and oropharyngeal depositions were quantified by gamma scintigraphyThe mean (SD)% ofthe delivered dose deposited in the lungs was 26.4 (4.3)% at 60 l/min and 21.1 (5.1)% at 30 l/min (P < 0.05), corresponding to mean lung depositions of 52.8 and 42.2 microg salbutamol, respectively. The distribution of drug within different lung regions did not vary significantly with inhaled flow rate. The data provided proof of concept for the novel inhaler device and the innovative drug formulation. In comparison with previous deposition data obtained with other DPIs, the lung deposition was relatively high, relatively reproducible (coefficient of variation 16% at 60 l/min) and relatively insensitive to the change in peak inhaled flow rate.

Evolution of dry powder inhaler design, formulation, and performance

Many companies are now prioritizing the development of dry powder inhalers (DPIs) above pressurized formulations of asthma drugs. A well-designed DPI and an appropriate powder formulation can optimize the effectiveness of inhaled drug therapy. A DPI must be able to deliver medications effectively for most patients, and an ideal inhaler would provide a dose that does not vary with inspiratory flow rate. Recent regulatory guidelines, among which the U.S. FDA draft guidance is the most stringent, demand consistent dose delivery from an inhaler throughout its life and consistency of doses from one inhaler to another. However, the properties of free micronized powders often interfere with drug handling and with drug delivery reducing dose consistency. Recent advances in formulation technology can increase lung dose and reduce its variability. While a perfect DPI may never exist, both device and formulation technology are evolving to rectify perceived deficiencies in earlier systems.

Improved lung delivery from a passive dry powder inhaler using an Engineered PulmoSphere powder

PURPOSE

To assess the pulmonary deposition and pharmacokinetics of an engineered PulmoSphere powder relative to standard micronized drug when delivered from passive dry powder inhalers (DPIs).

METHODS

Budesonide PulmoSphere (PSbud) powder was manufactured using an emulsion-based spray-drying process. Eight healthy subjects completed 3 treatments in crossover fashion: 370 microg budesonide PulmoSphere inhaled from Eclipse DPI at target PIF of 25 L x min(-1) (PSbud25), and 50 L x min(-1) (PSbud50), and 800 microg of pelletized budesonide from Pulmicort Turbuhaler at 60 L x min(-1)(THbud60). PSbud powder was radiolabeled with 99mTc and lung deposition determined scintigraphically. Plasma budesonide concentrations were measured for 12 h after inhalation.

RESULTS

Pulmonary deposition (mean +/- sd) of PSbud was 57+/-7% and 58+/-8% of the nominal dose at 25 and 50 L x min(-1), respectively. Mean peak plasma budesonide levels were 4.7 (PSbud25), 4.0 (PSbud50), and 2.2 ng x ml(-1) (THbud60). Median t(max) was 5 min after both PSbud inhalations compared to 20 min for Turbuhaler (P < 0.05). Mean AUCs were comparable after all inhalations, 5.1 (PSbud25), 5.9 (PSbud50), and 6.0 (THbud60) ng x h x ml(-1). The engineered PSbud powder delivered at both flow rates from the Eclipse DPI was twice as efficiently deposited as pelletized budesonide delivered at 60 L x min(-1) from the Turbuhaler. Intersubject variability was also dramatically decreased for PSbud relative to THbud.

CONCLUSION

Delivery of an engineered PulmoSphere formulation is more efficient and reproducible than delivery of micronized drug from passive DPIs.

In vitro and in vivo aspects of quantifying intrapulmonary deposition of a dry powder radioaerosol

Pulmonary delivery of pharmaceutical aerosols can be quantified using gamma scintigraphy. Technetium-99m, the most commonly used radionuclide in scintigraphic studies, cannot be incorporated into the drug molecule and, therefore, may be distributed differently from the drug itself, particularly if the drug is presented as a solid in a liquid suspension or as a dry powder formulation. This study demonstrated the importance of using conditions relevant to the in vivo situation in the in vitro characterisation of a dry powder aerosol of 99mTc-labelled lactose. The influence of inspiratory flow on the distribution of aerosol within the lungs was investigated in eight healthy subjects who inhaled the 99mTc-labelled lactose at four flows (30,40,60 and 80 l/min). No differences in penetration index (PI) or count density distribution of radioactivity were seen, indicating that regional distribution of aerosol in healthy airways was insensitive to differences in the inspiratory effort exerted by the subject while inhaling the experimental dry powder radioaerosol.

Comparison of beclomethasone dipropionate delivery by easyhaler dry powder inhaler and pMDI plus large volume spacer

Dry powder inhalers (DPIs) provide a means of delivering inhaled asthma drugs without the use of propellants. Easyhaler is a multidose DPI, delivering 200 doses of beclomethasone dipropionate (BDP), 200 microg/dose. A gamma scintigraphic study has been carried out in 10 healthy volunteers to compare the deposition of BDP from Easyhaler with that from a pressurized metered dose inhaler (pMDI) coupled to a Volumatic spacer device delivering 250 microg BDP per dose. The spacer was used without any pretreatment to reduce static charge on the spacer walls. The study was conducted according to an open, randomized, crossover design. The volunteers inhaled the study drug using optimal inhalation technique for both devices. Lung deposition of 99mTc-labeled BDP averaged 18.9% (SD 9.5%) of the metered dose for Easyhaler, and 11.2% (SD 5.3%) for pMDI plus spacer (p < 0.05); when the data were expressed as mass of BDP deposited in the lungs, the difference in lung deposition just failed to reach statistical significance (Easyhaler 37.8 microg; pMDI plus spacer 28.0 microg). Oropharyngeal deposition was significantly reduced by use of the spacer. The results of this study show that Easyhaler delivers drug more efficiently to the lungs than pMDI plus Volumatic spacer when no measures are taken to eliminate static charge on the spacer walls.

Measurement of peak inhalation rates with an in-check meter to identify an elderly patient's ability to use a turbuhaler

Dry powder inhalers are designed with resistance to airflow so that a respirable cloud of particles is generated during inhalation. Some of these devices require a certain inhalation rate to produce a consistent dose of respirable particles. The aim of the study was to determine the inhalation rate of elderly patients with chronic obstructive pulmonary disease (COPD) when they inhale through a Turbuhaler and assess the potential of the In-Check Meter to identify inhalation rates. Their peak inhalation rate using a normal inhalation, pre- and post-counselling, was measured using a Turbuhaler Trainer and an In-Check Meter. Spirometry was also measured. Seventy-four COPD patients with a mean (SD) age of 79.7 (8.4) years and forced expiratory volume in 1 sec (FEV1) 41.9 (12.8)% predicted. Pre-counselling 14 obtained a rate of <30 l min(-1) with the Turbuhaler Trainer, 31 from 30 to 40 min(-1), 23 between 40-60 l min(-1) and 6 > 60 l min(-1). The median (range) peak inhalation rates with the In-Check Meter were 50 (50-70), 70 (50-130), 100 (60-200) and 225 (200-250) l min(-1). Post-counselling 7, 16,41 and 10 achieved the respective peak inhalation rates using the Turbuhaler Trainer Similarly the In-Check inhalation rates were 50 (50-60), 70 (50-130), 90 (60-200) and 250 (200-270) l min(-1). The results highlight the potential of the In-Check Meter to identify patients' inhalation rates through dry powder inhalers.

Scintigraphic Assessment of the Regional Distribution and Kinetics of Pharmaceuticals

A lesser known use of imaging studies in drug development is to determine the patterns of deposition, biodistribution, and regional kinetics of drugs in the body. This kind of study is of most interest when the drug is intended for local action following topical administration by inhalation. Imaging provides a convenient noninvasive method for observing initial deposition patterns and their variations caused by variables of the drug’s formulation and delivery method. Though planar gamma imaging is the method that has most often been used, recent years have seen promising demonstrations of SPECT and PET imaging to provide three-dimensional and quantitative measurements of drug deposition. When the goal of a drug is direct local treatment of diseased tissue, delivery of that drug is an important therapeutic variable. Imaging studies allow the drug delivery to be measured and optimized before a drug formulation is committed to clinical trials.

A comparison of the lung deposition of budesonide from Easyhaler, Turbuhaler and pMDI plus spacer in asthmatic patients

Inhaled corticosteroids in pressurized metered does inhalers (pMDIs) are often delivered via a large volume spacer device, but these are bulky and inconvenient. Dry powder inhalers (DPIs) provide a highly portable and convenient propellant-free alternative to pMDIs for asthma maintenance therapy However, each DPI could have unique in vivo delivery characteristcs. In order to quantify the total and regional lung deposition of budesonide (200 microg) from (a) Easyhaler, (b) Turbuhaler and (c) pMDI plus Nebuhaler 750 ml spacer, a three-way randomized cross-over study was carried out in 12 mild to moderate asthmatic patients. Deposition was quantified by the imaging technique of gamma scintigraphy Optimal inhalation techniques were used throughout. Mean (SD) whole lung deposition (% metered dose) was similar for Easyhaler [18.5 (7.8) %] and Turbuhaler [21.8 (8.2) %], but was significantly higher for pMDI plus Nebuhaler [44.1 (10.0) %, P < 0.01]. The regional distribution patterns in the lungs were predominantly central for all three devices. Nebuhaler reduced oropharyngeal deposition significantly compared with the two DPIs. Easyhaler showed comparable deposition to Turbuhaler and hence drugs delivered by Easyhaler would be expected to have a similar clinical effect to those delivered by Turbuhaler in asthma maintenance therapy.

Pulmonary drug delivery from the Taifun dry powder inhaler is relatively independent of the patient's inspiratory effort

The Taifun dry powder inhaler (Leiras OY, Turku, Finland) is a breath-actuated, multidose device, each metered dose containing 200 micrograms of budesonide. A two-way randomized crossover gamma scintigraphic study was performed in 10 asthmatic patients to determine the in vivo deposition pattern of budesonide inhaled from the Taifun. In vitro radiolabelling validation studies demonstrated that the radiolabel could be used as an accurate marker to assess in vivo drug deposition. Patients used either maximal inspiratory effort (targeted peak inhalation flow 30 L/min) or submaximal inspiratory effort (targeted peak inhalation flow 15 L/min) on each study day. Mean (S.D.) whole lung deposition (% of metered dose) was 34.3 (5.8)% and 29.6 (5.9)% for the two inhalation flows. The intersubject coefficient of variation in lung deposition was less than 20% on both study days. Drug was deposited uniformly across the central, intermediate, and peripheral lung regions for maximal and submaximal inspiratory efforts. The study suggests that the Taifun is a superior drug delivery device compared with many other inhalers, in terms of the amount of drug deposited in the lungs, the reproducibility of the lung dose, and the relative flow--independence of lung deposition.

Anatomy and physiology in delivery: can we define our targets?

Studies have shown that the receptors for beta-agonists, inflammatory markers, and mast cells are distributed throughout the airways. Thus topical delivery of drug for the management of asthma requires an even spread throughout the lungs. Particles of 2-5 microm in diameter have the greatest potential to be deposited throughout the lungs during inhalation, by impaction and sedimentation. Inhaled products, therefore, are formulated such that almost half of the dose emitted during inhalation contains particles less than 5 microm in diameter. This is known as the fine-particle dose. Studies in adults (volunteers and asthmatic patients), using radiolabeling techniques, have shown that although the amount of drug deposited in the airways (total lung dose) from different inhaled products varies, the percentages of this amount distributed throughout the central, intermediate, and peripheral zones are fairly consistent. All that varies, therefore, is the density of the spread. Studies in children indicate that lung deposition is lower than in adults. Nevertheless, all factors which affect lung deposition in adults do so also in children. The lower lung deposition in children indicates the use of adult doses, and the importance of inhaler device and of inhalation technique. The even distribution of inhaled drug throughout the required therapeutic areas highlights the importance of the total lung dose.