Mixing energy as an adjustment tool for aerodynamic behaviour of an inhaled product: In-vitro and in-vivo effects.

This paper describes the development of a fixed dose dry powder combination of indacaterol maleate (Inda) and glycopyrronium bromide (Glyco) in Easyhaler® inhaler for a comparative pharmacokinetic (PK) study, as well as the outcome of such a study. The development aim was to produce formulations with three different in vitro dispersibility profiles for both Inda and Glyco. This so-called 'rake' approach allows for quantitation of the candidate formulations relative to the reference product Ultibro® Breezhaler® in terms of the key PK parameters. Three formulations (A, B and C) were produced based on the mixing energy concept. For both APIs, formulation A (lowest mixing energy) displayed the highest fine particle fractions and formulation C (highest mixing energy) the lowest. GMP manufacturing confirmed the performance of the three formulations. The candidate formulations were tested against the reference product in a single dose PK study in healthy volunteers. Clear differences in Inda plasma concentration profiles were observed between the treatments when administered concomitantly with charcoal, with Easyhaler A showing the highest Cmax value and Easyhaler C the lowest. Easyhaler B was bioequivalent to Ultibro Breezhaler with regard to the primary PK parameters of Inda, Cmax and AUC72h. For Glyco, Easyhaler formulations A, B and C provided lower peak concentrations than Ultibro Breezhaler. For AUC72h of Glyco, Easyhaler B was bioequivalent to the reference product. Additional measures for adjustment of formulation performance can be foreseen, whose effects can be predicted based on mixing energy theory.

Cradle-to-Grave Emission Reduction for Easyhaler Dry Powder Inhaler Product Portfolio.

INTRODUCTION: There is increasing pressure to prefer propellant-free inhaler devices over pressurized metered-dose inhalers (pMDI) due to environmental considerations. In this work, we present results from three life cycle assessments (LCAs) on Easyhaler dry powder inhaler product portfolio and assess the changes in environmental impact and carbon footprint (CF) of the products over time. METHODS: Three cradle-to-grave LCAs were conducted in 2019, 2021, and 2023. The 2019 assessment covered four products while 2021 and 2023 assessments included all six products in the portfolio. LCA for the protective cover sometimes used with Easyhaler was conducted in 2023. In addition to CF, nine other environmental impact categories were assessed to ensure that no burden shifting occurs. RESULTS: During the study period, the non-weighted average CF of the Easyhaler decreased by 11.2%. For individual products, the decrease varied from 5.0 to 6.8% between the assessments. In the latest assessment, the average CF of Easyhaler was 547 gCO2e with a range of 452-617 gCO2e. The LCA of the protective cover was assessed for the first time in 2023 and had a CF of 66 gCO2e. CONCLUSIONS: Our results show that the climate impact of pharmaceutical products can be reduced without making changes to the product itself. The CF of Easyhaler products is in agreement with the lower end of the CF range previously reported for dry powder inhalers. Climate impact from the protective cover was one-tenth compared to the climate impact from the product itself.

Urgent actions are needed to tackle the climate crisis. The use of propellant-free inhalers such as dry powder inhalers can reduce the environmental impact of inhaler treatment. The environmental impact of Easyhaler dry powder inhaler portfolio was assessed using a life cycle assessment. The assessments were conducted using cradle-to-grave technique, which means that everything starting from raw material acquisition to production, transportation, use, and disposal is included in the assessment. The assessment was conducted repeatedly in 2019, 2021, and 2023. Repeating the assessment helps in monitoring changes in the environmental impact of Easyhaler. The results show that the average carbon footprint of Easyhaler is 547 gCO₂e and that is similar to the carbon footprint of other dry powder inhalers. The carbon footprint of Easyhaler has decreased 11.2 % over time. Emissions related to the manufacturing decreased the most because of increased energy efficiency and use of carbon-free and renewable energy. The carbon footprint of the cover, which may be used with Easyhaler product, was low (66 gCO₂e) compared to Easyhaler.

A non-interventional switch study in adult patients with asthma or COPD on clinical effectiveness of salmeterol/fluticasone Easyhaler® in routine clinical practice.

BACKGROUND: Selection of the most appropriate device for a switch from one inhaler to an equivalent product is known to have a major impact on clinical outcomes in patients with asthma or chronic obstructive pulmonary disease (COPD). Salmeterol/fluticasone propionate (S/F) Easyhaler® has been demonstrated to be therapeutically equivalent with a reference product. However, no data on real-life effectiveness are currently available for patients switching to S/F Easyhaler from another S/F inhaler. METHODS: The aim of this prospective, open, multicenter, non-interventional study was to assess clinical effectiveness of propionate S/F Easyhaler in adult asthma and COPD patients switched from another inhaler. The primary endpoints were Asthma Control Test (ACT) and COPD Assessment Test (CAT). Secondary endpoints included assessments of patient satisfaction and preference and physician/nurse perception on S/F Easyhaler use. The study included three visits during a 12-week follow-up. RESULTS: A total of 211 patients (160 with asthma; 51 with COPD) were included in the analyses. In patients with asthma, there was a statistically significant increase in the mean ACT score at week 12 (20.2 ± 3.9) compared with the baseline (18.6 ± 4.1), with a mean increase of 1.6 (±3.5) points (p < 0.0001). In patients with COPD, CAT score persisted from baseline (19.9 ± 8.6) to week 12 (19.6 ± 7.0). Patients were significantly more satisfied with Easyhaler and most patients preferred Easyhaler over their previous inhaler. The physicians/nurses reported that it was 'very easy' to teach the use of Easyhaler and the training took less than 5 minutes in most cases. CONCLUSION: The results from this prospective real-life clinical study indicate better or at least similar treatment control of asthma and COPD after switching to S/F Easyhaler from another S/F inhaler. This study also shows that S/F Easyhaler was favored by the patients and that it is easy to teach, learn and use in a real-life setting.The reviews of this paper are available via the supplemental material section.

Inspiratory Flow Parameters Through Dry Powder Inhalers in Healthy Volunteers and Patients with Chronic Obstructive Pulmonary Disease (COPD): Device Resistance Does Not Limit Use in COPD.

INTRODUCTION: Achieving correct inhalation technique through an inhaler to ensure effective drug delivery is key to managing symptoms in patients with chronic obstructive pulmonary disease (COPD). However, many patients struggle to use their inhalers correctly, with the resultant reduction in therapeutic benefit. Consequently, appropriate inhaler choice is important to maximize clinical benefit. The primary objective of this study was to characterize inspiratory flow parameters across two Easyhaler® inhalers and the HandiHaler® inhaler in patients with COPD and healthy volunteers. METHODS: In this randomized, open-label, crossover study, subjects (100 patients with COPD; 100 healthy volunteers) were trained to perform inhalations of placebo powder via two variants of Easyhaler and placebo capsules via the HandiHaler inhalers. Subjects then performed three placebo inhalations through each inhaler in a random sequence. Inspiratory flow parameters were assessed, including peak inspiratory flow (PIF), for each inhaler. A parallel sub-study was conducted in patients with COPD from the main study to assess correct use of the inhalers, patient's preference, ability to learn to use the inhalers, and the feasibility of the In-Check Dial device to measure PIF values. RESULTS: Mean PIF rates and inspiratory volumes through the three inhalers were similar between patients with COPD and healthy volunteers, and all subjects achieved the 30 L/min PIF required for effective use of Easyhaler. Almost 70% of the 88 patients enrolled in the sub-study used the Easyhaler and HandiHaler inhalers without errors. The Easyhaler was preferred by 51% of patients, while 25% favored the HandiHaler. Teaching the use of both inhalers to almost 70% of patients was very easy. The In-Check Dial PIF values and those obtained via spirometry were strongly correlated (p<0.0001) for all three inhalers. CONCLUSION: The respiratory performance of patients with COPD does not appear to be a limiting factor in the use of Easyhaler.

Patients with asthma or chronic obstructive pulmonary disease (COPD) can generate sufficient inspiratory flows via Easyhaler® dry powder inhaler: a pooled analysis of two randomized controlled trials.

BACKGROUND: To evaluate whether patients of varying ages and lung function with asthma or those with chronic obstructive pulmonary disease (COPD) can achieve sufficient inspiratory flows for effective use of the fixed-dose combination of salmeterol-fluticasone propionate and budesonide-formoterol dispensed with the Easyhaler® (EH) device-metered, multi-dose dry powder inhaler (DPI). METHODS: A pooled analysis of two randomized, multicenter, crossover, open-label studies (NCT01424137; NCT009849061) was conducted to characterize inspiratory flow parameters across the EH, Seretide Diskus (DI) and Symbicort Turbuhaler (TH) inhalers in patients with asthma and/or COPD of varying severity. The primary endpoint was peak inspiratory flow (PIF) rate through the EH. RESULTS: The intent-to-treat population comprised 397 patients; 383 patients were included in the per-protocol (PP) population. The mean PIF (standard deviation) values through the EH in patients <18 and ≥18 years of age with asthma and in those with COPD, were similar: 61.4 (11.5), 69.7 (13.5), and 61.9 (13.2) L/min, respectively. These flow rates correspond to pressure drops of 5.05 (1.80), 6.52 (2.34) and 5.19 (2.07) kPa, respectively. In total, 380 (99.2%) of patients in the PP population were able to generate a PIF rate through the EH of ≥30 L/min, which is required to enable consistent dose delivery from the DPI; there was a moderate direct association between age and PIF in younger patients with asthma, but this was inverse and less apparent in adult patients with asthma and/or those with COPD. Height and weight were also moderately correlated with PIF. Stronger associations with PIF were observed for some lung function parameters, particularly native PIF and forced inspiratory vital capacity. CONCLUSIONS: Over 99% of patients with asthma and/or COPD were able to inhale through the EH with an adequate PIF rate, irrespective of age, or severity of airway obstruction. This confirms that patients with asthma and/or COPD can achieve inspiratory flows via the EH DPI that are sufficient for its effective use.

Patient Inspiratory Maneuver Performance; Peak Lungpower, Acceleration and Volume.

Background: Use of drug delivery devices between nebulizers, dry powder inhalers (DPIs), or metered dose inhalers (MDIs), for treating patients with asthma and chronic obstructive pulmonary disease (COPD), is based on patients' capability of coordinating the inhalation maneuver and achieving sufficient airflow. There are limited data available with regard to how patients meet the requirements of successful inhalation performance, and how the concept of inspiratory lungpower could be applied. The aim of this work was to study the patient inspiratory airflow profile performance in large data sets. We analyzed how the Kamin-Haidl inhalation criteria were met by patients with DPIs such as Easyhaler for combination therapy (EH-combi), Easyhaler for monotherapy (EH-mono), Diskus, and Turbuhaler (TH), and applied peak lungpower instead of peak inspiratory flow rate as an indicator of patient performance. Materials and Methods: Data sets gathered in two previous studies for DPIs, that is, EH-combi, EH-mono, Diskus, and TH, were used to analyze how inspiratory lungpower representing inspiratory muscle power, flow acceleration, and volume after peak met the inhalation criteria. The measured patient airflow profiles through inhalers were assessed for patients with asthma or COPD. Results: Based on the Kamin-Haidl inhalation criteria, successful inhalation requirements were met with EH-combi in 96.1% and with EH-mono in 92.6% of patients. The success rates were 89.5% and 84.6% with Diskus and TH, respectively, (p < 0.0001 between devices). In patients with asthma or COPD, the mean lungpower was 7.51 and 6.15 W for EH-combi, 8.79 and 6.88 W for EH-mono, 7.18 and 4.36 W for Diskus, and 9.65 and 6.86 W for TH, respectively, when patients followed the manufacturer's written instructions. Conclusions: Lungpower applied to the Kamin-Haidl inhalation criteria concept could be an applicable method for reviewing patient performance for different DPIs despite DPIs' characteristic differences in airflow resistance. In light of these results, DPIs provide a feasible treatment option for a large majority of respiratory patients.

In Vitro Flow Rate Dependency of Delivered Dose and Fine Particle Dose of Salmeterol/Fluticasone Propionate Easyhaler and Seretide Diskus with Patient Flow Rates Collected in a Randomized Controlled Trial.

BACKGROUND: The Easyhaler® device-metered dry powder inhaler containing Salmeterol and Fluticasone propionate (S/F) has been developed for the treatment of patients with asthma and chronic obstructive pulmonary disease (COPD). We report two studies which evaluated the in vitro flow rate dependence of delivered dose (DD) and fine particle dose (FPD) of S/F Easyhaler versus Seretide Diskus®. METHODS: A randomized controlled trial (RCT) assessed inspiratory flow parameters of S/F Easyhaler and Seretide Diskus in subgroups of patients with asthma (children, adolescents and adults, and elderly) and in COPD patients. The 10th, 50th, and 90th percentile airflow rates were determined and utilized in vitro, to evaluate flow rate dependence of DD and FPD. Flow rate dependence was evaluated relative to the result obtained at the 50th percentile and any values deviating from 100% indicated flow rate dependence. The volumetric flow rate dependence (Q) index derived from FPD at 10th and 90th percentile airflows was also evaluated. RESULTS: Overall, 227 patients were enrolled and randomized; 216 completed the RCT. In total, 55.5% of patients were female, and the mean age was 46.3 years. Clinically relevant airflow rates (46, 68, and 85 L/min for S/F Easyhaler and 44, 71, and 96 L/min for Seretide Diskus) were carried forward into the in vitro study, which demonstrated similar flow rate dependence of DD and FPD for S/F Easyhaler compared with Seretide Diskus; all values were within ±15% limits across the 10th, 50th, and 90th percentile airflow rates. Q index results suggested that both S/F Easyhaler and Seretide Diskus are medium airflow-dependent products. CONCLUSIONS: Similar in vitro flow rate dependence of DD and FPD was demonstrated for S/F Easyhaler compared with Seretide Diskus, across a range of clinically relevant airflow rates, collected from patients with asthma and COPD.

Pharmacokinetics of Salmeterol and Fluticasone Propionate Delivered in Combination via Easyhaler and Diskus Dry Powder Inhalers in Healthy Subjects.

BACKGROUND: Easyhaler® dry powder inhaler (DPI) containing salmeterol and fluticasone propionate was developed for the treatment of asthma and chronic obstructive pulmonary disease. Three different Salmeterol/fluticasone Easyhaler test products (Orion Pharma, Finland) were compared against the reference product Seretide® Diskus® DPI (GlaxoSmithKline, United Kingdom) to study whether any of the test products are bioequivalent with the reference. METHODS: Open and randomized pharmacokinetic four-period crossover study on 65 healthy volunteers was performed in a single center to compare the lung deposition and total systemic exposure of salmeterol and fluticasone propionate after administration of single doses (two inhalations of 50/500 µg/inhalation strength) in fasting conditions. Blood samples were drawn before dosing and at frequent time points between 2 minutes and 34 hours after dosing for determination of drug concentrations. The primary variables for total systemic exposure and lung deposition of fluticasone propionate were maximum concentration of the concentration-time curve (Cmax) and area under the concentration-time curve from time zero to the last sample with quantifiable concentration (AUCt). For salmeterol, the primary variables for total systemic exposure were Cmax and AUCt and for lung deposition Cmax and AUC up to 30 minutes after study treatment administration (AUC30min). RESULTS: One of the Easyhaler test products met all the criteria for bioequivalence with the reference. The 96.7% confidence intervals (CIs) for the test/reference ratios of fluticasone propionate Cmax and AUCt were 0.9901-1.1336 and 0.9448-1.0542, respectively. Ninety percent CIs for salmeterol Cmax, AUC30min, and AUCt ratios were 1.0567-1.2012, 1.0989-1.2255, and 1.0769-1.1829, respectively. Median salmeterol time to maximum concentration (tmax) was 4.0 minutes. Median fluticasone propionate tmax was from 1.5 to 2.0 hours. Terminal elimination half-life was 11 hours for salmeterol and 9-10 hours for fluticasone propionate. CONCLUSIONS: Salmeterol/fluticasone Easyhaler was shown to be bioequivalent with the reference product.

Equivalent bronchodilation with budesonide/formoterol combination via Easyhaler and Turbuhaler in patients with asthma.

BACKGROUND: Therapeutic equivalence of Budesonide/formoterol Easyhaler compared to Symbicort Turbuhaler has been previously demonstrated with in vitro and pharmacokinetic studies. This study was performed to confirm equivalent bronchodilator efficacy of the products in asthmatic patients. METHODS: A randomised, single-dose, 4-period crossover study was carried out in a double-blind, double-dummy manner in 11 study sites. The studied doses were 320/9 µg and 1280/36 µg of budesonide/formoterol delivered by Easyhaler and Turbuhaler. Spirometry was performed before and 10 min, 20 min and 1, 2, 3, 4, 6, 8, 10 and 12 h after administration of the study treatments. The primary efficacy endpoint was average 12-h forced expiratory volume in 1 s (FEV1). The secondary efficacy endpoints were maximum FEV1 and FEV1 at 12 h post-dose. RESULTS: 72 asthma patients with reversible airway obstruction were randomised to receive study treatments. 53 patients completed all study periods according to the protocol and had sufficient data available to calculate the primary endpoint. They were included in the per-protocol analyses. The assay sensitivity of the study was shown as the common slope of average 12-h FEV1 between doses was 0.063 (95% CI 0.032-0.093) and showed statistical significance (p < 0.001). In equivalence testing, the difference in average 12-h FEV1 between the treatments (Easyhaler-Turbuhaler) was 0.013 l at the lower dose and -0.028 l at the higher dose, and their 95% confidence intervals (CIs) (-0.047 to 0.073 and -0.087 to 0.032, respectively) fell within the range of a clinically non-relevant difference. The results of the secondary efficacy endpoints were in line with the results of the primary endpoint. All treatments were well tolerated. CONCLUSIONS: The results confirm equivalent bronchodilator efficacy of Budesonide/formoterol Easyhaler compared to Symbicort Turbuhaler. TRIAL REGISTRATION: This trial was registered on ClinicalTrials.gov, Identifier: NCT02308098.

Equivalent Lung Dose and Systemic Exposure of Budesonide/Formoterol Combination via Easyhaler and Turbuhaler.

BACKGROUND: Easyhaler(®) device-metered dry powder inhaler containing budesonide and formoterol fumarate dihydrate (hereafter formoterol) for the treatment of asthma and chronic obstructive pulmonary disease has been developed. The current approvals of the product in Europe were based on several pharmacokinetic (PK) bioequivalence (BE) studies, and in vitro-in vivo correlation (IVIVC) modeling. METHODS: Four PK studies were performed to compare the lung deposition and total systemic exposure of budesonide and formoterol after administration of budesonide/formoterol Easyhaler and the reference product, Symbicort Turbuhaler. The products were administered concomitantly with oral charcoal (lung deposition) and in two of the studies also without charcoal (total systemic exposure). Demonstration of BE for lung deposition (surrogate marker for efficacy) and non-inferiority for systemic exposure (surrogate marker for safety) were considered a proof of therapeutic equivalence. In addition, IVIVC models were constructed to predict study outcomes with different reference product fine particle doses (FPDs). RESULTS: In the first pivotal study, the exposure and lung dose via Easyhaler were higher compared to the reference product (mean comparison estimates between 1.07 and 1.28) as the FPDs of the reference product batch were low. In the following studies, reference product batches with higher FPDs were utilized. In the second pivotal study, non-inferiority of Easyhaler compared to Turbuhaler was shown in safety and BE in efficacy for all other parameters except the formoterol AUCt. In the fourth study where two reference batches were compared to each other and Easyhaler, budesonide/formoterol Easyhaler was bioequivalent with one reference batch but not with the other having the highest FPDs amongst the 28 reference batches studied. In the IVIVC based study outcome predictions, the test product was bioequivalent with great proportion of the reference batches. For the test product and the median FPD reference product BE was predicted. CONCLUSIONS: Equivalence regarding both safety and efficacy between budesonide/formoterol Easyhaler and Symbicort Turbuhaler was shown based on totality of evidence from the PK studies and IVIVC analyses, and therefore, therapeutic equivalence between the products can be concluded. The results of the PK studies are likely dependent on the variability of FPDs of the reference product batches.

Evaluation of in vitro and in vivo flow rate dependency of budesonide/formoterol Easyhaler(®).

BACKGROUND: The Easyhaler(®) (EH) device-metered dry powder inhaler containing budesonide and formoterol is being developed for asthma and chronic obstructive pulmonary disease (COPD). As a part of product optimization, a series of in vitro and in vivo studies on flow rate dependency were carried out. METHODS: Inspiratory flow parameters via EH and Symbicort(®) Turbuhaler(®) (TH) inhalers were evaluated in 187 patients with asthma and COPD. The 10(th), 50(th), and 90(th) percentile flow rates achieved by patients were utilized to study in vitro flow rate dependency of budesonide/formoterol EH and Symbicort TH. In addition, an exploratory pharmacokinetic study on pulmonary deposition of active substances for budesonide/formoterol EH in healthy volunteers was performed. RESULTS: Mean inspiratory flow rates through EH were 64 and 56 L/min in asthmatics and COPD patients, and through TH 79 and 72 L/min, respectively. Children with asthma had marginally lower PIF values than the adults. The inspiratory volumes were similar in all groups between the inhalers. Using weighted 10(th), 50(th), and 90(th) percentile flows the in vitro delivered doses (DDs) and fine particle doses (FPDs) for EH were rather independent of flow as 98% of the median flow DDs and 89%-93% of FPDs were delivered already at 10(th) percentile air flow. Using±15% limits, EH and TH had similar flow rate dependency profiles between 10(th) and 90(th) percentile flows. The pharmacokinetic study with budesonide/formoterol EH in healthy subjects (n=16) revealed a trend for a flow-dependent increase in lung deposition for both budesonide and formoterol. CONCLUSIONS: Comparable in vitro flow rate dependency between budesonide/formoterol EH and Symbicort TH was found using the range of clinically relevant flow rates. The results of the pharmacokinetic study were in accordance with the in vitro results showing only a trend of flow rate-dependant increase in lung deposition of active substances with EH.

Clinically equivalent bronchodilatation achieved with formoterol delivered via Easyhaler and Aerolizer.

BACKGROUND: User-friendly devices for the delivery of asthma drugs are needed to enhance treatment compliance. Formoterol inhalation powder has been developed to Easyhaler multidose powder inhaler to enable the treatment of all asthma severities with the same device. OBJECTIVES: This double-blind, double-dummy, single- dose, placebo-controlled, cross-over study aimed to demonstrate the non-inferiority of the bronchodilating effect of formoterol 12 microg delivered via Easyhaler versus via Aerolizer. In addition, dose responses following placebo, 12-microg and 48-microg doses of formoterol via Easyhaler were compared. Furthermore, onset and duration of action, and safety of formoterol inhaled using the two inhalers were compared. METHODS: Sixty-seven adult asthmatic subjects showing >or=15% increase in forced expiratory volume in 1 s (FEV(1)) after short-acting sympathomimetic inhalation were enrolled and completed the study. The study comprised screening and 4 treatment days, with each subject inhaling a single 12-mug dose of formoterol via Easyhaler, a 12-microg dose via Aerolizer, a 48-microg dose via Easyhaler or placebo. Repeat spirometry and vital sign measurements were performed for 12 h during treatment days. The primary efficacy variable was the area under the flow volume curve (AUC(0-12)) of FEV(1). Secondary efficacy variables comprised maximum FEV(1 )(FEV(1max)), forced vital capacity (FVC), and the need of rescue medication during the treatment days. Safety was evaluated by determining blood pressure, heart rate and the number of adverse events (AEs). RESULTS: Results showed the non-inferiority of the bronchodilating effect of 12 microg formoterol via Easyhaler compared to Aerolizer. The Easyhaler-Aerolizer ratio for AUC(0-12) of FEV(1 )was 0.991 (95% confidence interval from 0.969 to 1.013). No statistically significant differences emerged for secondary efficacy variables. A statistically significant dose response was seen following placebo, 12- and 48-microg doses in FEV(1). No safety differences emerged for the 12-microg dose inhaled via Easyhaler or Aerolizer, but the incidence of AEs was higher following formoterol 48 microg and placebo treatments. CONCLUSIONS: Formoterol delivered via Easyhaler was therapeutically equivalent to Aerolizerat the 12-microg dose. The 48-microg dose via Easyhaler demonstrated statistically significantly greater bronchodilation but showed an increased occurrence of AEs.

Equivalent lung deposition of budesonide in vivo: a comparison of dry powder inhalers using a pharmacokinetic method.

AIMS: The aim of this study was to compare lung deposition of budesonide administered from two dry powder inhalers, Giona Easyhaler 200 microg/dose and Pulmicort Turbuhaler 200 microg/dose by utilizing a pharmacokinetic method. METHODS: This was an open, randomized, crossover study in 33 healthy subjects. The study consisted of four treatment periods separated by at least 4 wash-out days. Equivalence in lung deposition was assessed after a single inhaled 1000 microg (5 x 200 microg) dose of budesonide from Giona Easyhaler and from Pulmicort Turbuhaler. Concomitant oral charcoal administration (40 g) was used to prevent gastrointestinal (GI) absorption of budesonide. The efficacy of the charcoal was studied after oral administration of a budesonide 2 mg capsule. The subjects were trained to inhale the study drugs with controlled flow rates, which resulted in an equal pressure drop (4 kPa) across both inhalers. Venous blood samples for the determination of budesonide concentrations in plasma were drawn before and at predetermined time points up to 8 h after drug administration. Budesonide concentrations in plasma were determined using liquid chromatography-tandem mass spectrometry. Several pharmacokinetic parameters were estimated, the area under the budesonide concentration in plasma vs time curve from dosing to infinity (AUC(0, infinity)) being the primary response variable. Equivalence in lung deposition was concluded if the 90% confidence interval (CI) for the Easyhaler : Turbuhaler ratio of AUC(0, infinity) fell within the limits of 0.8-1.25. RESULTS: The mean AUC(0,infinity) value after Easyhaler treatment was 3.48 (standard deviation (SD) 0.93) ng ml(-1) h and after Turbuhaler treatment 3.46 (1.13) ng ml(-1) h. The Easyhaler : Turbuhaler AUC(0, infinity) ratio was 1.02 and the 90% CI was from 0.96 to 1.09. The mean C(max) values (SD) for budesonide in plasma after Easyhaler and Turbuhaler treatments were 1.22 (0.41) ng ml(-1) and 1.29 (0.44) ng ml(-1), respectively. There was no statistically significant difference (P = 0.39) between the median t(max) for Easyhaler (30 min) and Turbuhaler treatment (23 min). Charcoal impaired the GI absorption of budesonide by 96%. The occurrence of adverse events was similar during both treatments. CONCLUSIONS: The results show that the lung deposition of budesonide from Giona Easyhaler 200 microg/dose and Pulmicort Turbuhaler 200 microg/dose dry powder inhalers is equivalent. The charcoal block used to prevent GI absorption of swallowed budesonide was found to be effective.