Use Of Dry Powder Inhalers Research Articles

Exhalation immediately before inhalation optimizes dry powder inhaler use

Objective: Although exhalation immediately prior to inhalation (EPI) from dry powder inhalers (DPIs) is universally advised, its benefit has not been investigated. The objective of this study to assess the effects of EPI on inhaled flow from a DPI. Methods: We measured peak inhaled flow rate (PIFR) and inhaled gas volume of 25 volunteers unfamiliar with DPIs. They inhaled strongly and deeply through a flow meter either with or without EPI before and after connecting Turbuhaler® or Diskus®. Results: Median PIFR increased significantly with EPI both without connection to DPIs (178.8 versus 140.4 L min−1), and with connection to Diskus® (75.6 versus 67.8 L min−1), or to Turbuhaler® (51.0 versus 48.0 L min−1). As a result, the number of subjects whose PIFR exceeded 60 L min−1 was significantly increased with connection to either Diskus® (76 versus 64%) or to Turbuhaler® (24 versus 4%). EPI significantly increased median inhaled volume both without connection to DPIs (2.84 versus 1.84 L), and with connection to Diskus® (1.95 versus 1.66 L), or to Turbuhaler® (1.86 versus 1.28 L). EPI significantly increased F0.2 (flow at 0.2 s after onset of inhalation) and AC30 (flow acceleration at 30 L min−1), parameters representing the rate of flow increase during the early phase of inhalation, in all the three groups. Conclusions: EPI increases PIFR which may augment drug dispersion and facilitate fine particle generation from a DPI.

Evaluation of cariogenic potential of dry powder inhalers: A case-control study

Objective:Dry powder inhalers (DPIs) are commonly employed in the management of asthma and other diseases with airway obstruction. A causal relationship of DPI use and occurrence of dental caries has been speculated. The present case-control study was therefore designed to examine the potential link between dental caries and specific use of dry powder inhalers in patients with bronchial asthma.Materials and Methods:The present study was conducted on 100 asthmatic patients aged between 10 and 45 years who were using DPIs for at least one year. The control group (n = 100) was selected from non-asthmatic individuals and were matched with the study group with respect to age, gender, and socio-economic status.Results:The results revealed that asthmatic subjects exhibited higher occurrence of dental caries in comparison to control group, but the difference was statistically non-significant. The mean decayed, missing, and filled teeth (DMFT) indices scores in asthmatic and control group were found to be 1.71 ± 2.34 SD and 1.46 ± 1.89 SD (P = 0.408), respectively. Likewise, the mean decayed, missing, and filled surfaces (DMFS) indices scores in both the groups were 2.41 ± 3.84 SD and 2.34 ± 4.48 SD (P = 0.90). However, increased frequency of DPI use was associated with significant risk of caries (P = 0.01). It has been observed that oral rinsing after an inhaler use limited the occurrence of dental caries to a certain extent although was non significant.Conclusions:Dry powder inhaler use in patients with bronchial asthma was not associated with significant risk of dental caries.

Spray Drying of Mannitol as a Drug Carrier—The Impact of Process Parameters on Product Properties

Powders intended for the use in dry powder inhalers have to fulfill specific product properties, which must be closely controlled in order to ensure reproducible and efficient dosing. Spray drying is an ideal technique for the preparation of such powders for several reasons. The aim of this work was to investigate the influence of spray-drying process parameters on relevant product properties, namely, surface topography, size, breaking strength, and polymorphism of mannitol carrier particles intended for the use in dry powder inhalers. In order to address this question, a full-factorial design with four factors at two levels was used. The four factors were feed concentration (10 and 20% [w/w]), gas heater temperature (170 and 190°C), feed rate (10 and 20 L/h), and atomizer rotation speed (6,300 and 8,100 rpm). The liquid spray was carefully analyzed to better understand the dependence of the particle size of the final product on the former droplet size. High gas heater temperatures and low feed rates, corresponding to high outlet temperatures of the dryer (96–98°C), led to smoother particles with surfaces consisting of smaller crystals compared to those achieved at low outlet temperatures (74–75°C), due to lower gas heater temperatures and higher feed rates. A high solution concentration of the feed also resulted in the formation of comparably rougher surfaces than a low feed concentration. Spray-dried particles showed a volume-weighted mean particle size of 71.4–90.0 µm and narrow particle size distributions. The mean particle size was influenced by the atomizer rotation speed and feed concentration. Higher rotation speeds and lower feed concentrations resulted in smaller particles. Breaking strength of the dried particles was significantly influenced by gas heater temperature and feed rate. High gas heater temperatures increased the breaking strength, whereas high feed rates decreased it. No influence of the process parameters on the polymorphism was observed. All products were crystalline, consisting of at least 96.9% of mannitol crystal modification I.

The impact of spray drying outlet temperature on the particle morphology of mannitol

The motivation for this study was to find an adequate substitute for lactose as carrier in dry powder inhalers and to overcome some drawbacks inherent to lactose. Mannitol appears to be the ideal replacement of lactose because it lacks the risk of transmitting the transmissible spongiform encephalopathy, mannitol does not carry reducing groups, that may cause chemical interactions with drugs such as proteins, and is highly crystalline even upon spray drying. Spray drying in turn is a dedicated technology to prepare carrier particles for dry powder inhalers. Typically spherical particles are generated constituting comparable interparticle forces to every drug particle attached to their surface. This study shows, that mannitol particles of different surface roughness can be prepared by spray drying at different outlet temperatures, providing the opportunity of tailoring the contact area respectively the interparticle interactions between the drug and the carrier. The emergence of different surface roughness was attributed to different crystallization mechanisms. Surface roughness was quantified by confocal laser-scanning microscopy. Quantitative Raman spectroscopy revealed, that the spray dried products consist mainly of the thermodynamically stable modification I° besides small amounts (5 to 15%) of the metastable modification II, irrespective of the drying temperature and the crystallization mechanisms taking place. This renders mannitol a most suitable substitute of lactose for the use in dry powder inhalers.

The formulation and evaluation of salbutamol dry powder inhalation mixtures with the Rotahler device

Metered dose inhalers (MDIs) contain chlorofluorocarbons, widely known, to affect the environment adversely. These chemicals deplete the ozone layer. The use of dry powder inhalers is therefore in the ascendance to replace MDIs for delivery of medicines to the respiratory tract. In this study we have formulated dry powder inhalation mixtures containing salbutamol sulphate using recrystallised lactose or modified lactose prepared by a proprietary method to smoothen the surface texture of the lactose. The effect of the proprietary method used to smoothen the surface texture of the recrystallized lactose was evaluated with the ROTAHALERTM device and the Twin Impinger BP in deposition tests. The respirable fraction obtained was higher in inhalation mixtures containing the recrystallized lactose compared to those containing regular lactose used as basis for comparison.Keywords: formulation, salbutamol, evaluation, powder, inhalation, Rotahaler

The formulation and evaluation of Disodium cromoglycate dry powder inhaler mixtures using the Rotahaler device

Inhalation of drugs offers the opportunity to treat diseases of the respiratory tract. In this drug delivery mode, the use of dry powder inhalers is preferred compared to pressurized metered dose inhalers. Metered dose inhalers contain chlorofluorocarbons known to affect the environment adversely. In this study we have formulated inhalation mixtures containing disodium cromoglycate using modified lactose. The effect of a proprietary method used to smoothen the surface of the modified lactose used as carrier for drug in the inhalation mixtures was determined with the ROTAHALERTM device and the Twin Impinger Apparatus BP. The respirable fraction obtained was higher in inhalation mixtures containing modified lactose compared to mixtures containing regular lactose, the control.Keywords: dry powder inhalers, respirable fraction, disodium cromoglycate, Rotahaler device, Twin Impinger BPJournal of Pharmaceutical and Allied Sciences, Vol. 7 No. 3 (2010)

Deposition of Disodiun Cromoglycate and Salbutamol from a multiple-dose dry powder inhaler device

Inhalation of drugs offers the opportunity to treat diseases of the respiratory tract. The use of dry powder inhalers is preferred to metered dose inhalers and nebulizers in this mode of drug delivery delivery. A multi-dose dry powder inhaler device, KCHALER TM device, which delivers drugs passively into the respiratory tract, was developed in our laboratories. In this study, we report the deposition pattern of disodium cromoglycate and salbutamol obtained with the device in the Twin Impinger BP. The effect of type of mouthpiece attached to the KCHALERTM device, on respirable fraction obtained with the Twin Impinger BP was also evaluated. The surface texture of carrier particles used in the formulation of the inhalation mixes and type of mouthpiece, affected the respirable fraction obtained in mixtures containing salbutamol and disodium cromoglycate. Keywords: Dry powder inhalers, multiple-dose dry powder inhaler device, salbutamol deposition, Twin impinger BPJournal of Pharmaceutical and Allied Sciences, Vol. 7 No. 1 (2010)

Formulation and in vitro evaluation of highly dispersive insulin dry powder formulations for lung administration

The aim of this work was to develop highly dispersible and dry formulations of insulin for use in dry powder inhalers (DPIs) using high-pressure homogenisation (HPH) and spray-drying. Several formulations were evaluated, including formulations spray-dried without excipients and formulations coated with lipids. A physiological lipid composition based on a mixture of cholesterol and phospholipids was used to form the coating film around micronised drug particles. The production technique and excipients were chosen in order to limit the degradation of the active ingredient. The resulting powders exhibited a size and shape suitable for the deep lung deposition of drugs, and good aerodynamic features were obtained for the different formulations tested, with fine particle fractions between 46% and 63% vs. 11% for raw insulin powder. The presence of a lipid coating of up to 30% (w/w) did not significantly affect the aerodynamic behaviour, and the coated formulations also exhibited a decreased residual moisture content of between 2.3% and 3.7% vs. 4.8% for raw insulin, which should improve the long-term stability of the protein formulations. No degradation of the insulin molecule occurred during the HPH/spray-drying process, as it was shown using an HPLC method (insulin content between 98.4% and 100.5%), and the content in high molecular weight proteins, assessed using a gel filtration method, stayed below 0.4%.

Applications of Capsule Dosing Techniques for Use in Dry Powder Inhalers

Dry powder inhaler (DPI) devices that utilize two-piece capsules as the dose-holding system can require specialized dosing equipment to fill the capsules. Such products are known as 'premetered' because they contain previously measured doses in a dose carrier (the capsule). The capsule is either inserted into the device during manufacture or by the patient prior to use. The dose is inhaled directly from the device/premetered unit by the patient. Regardless of DPI design, the most crucial attributes are the reproducibility of the discharged dose and the particle size distribution of the drug within that dose. Filling inhalation powders into capsules often requires specialized equipment in order to handle the very low weights that are often contained in each dose. The equipment typically needs to incorporate in-process checks to confirm the filling process has been correctly performed, with the ability to reject any under- or over-filled capsules, in line with established quality criteria. In the majority of cases, such processing equipment is maintained in a temperature and humidity controlled environment to avoid moisture uptake and potential powder aggregation and, in particular, to ensure the powder is free flowing on introduction into the capsule. This ensures that the emitted dose is maximized and controlled according to industry guidelines and that the fine particle fraction provides an optimum clinical benefit. Several methods of dosing precise doses of powder into capsules are available and include dosator technology and tamp processes, as well as equipment that utilize the 'pepper-shaker' or 'pepper-pot' principle for the accurate dispensing of powders. This article reviews the suitability of each method with respect to dosing inhalation powder into capsules for use in DPI devices, and discusses why the pepper-pot principle could offer a number of clear benefits.

The use of dry powder inhaler devices by elderly patients suffering from chronic obstructive pulmonary disease

Twenty-five COPD patients, aged 65years or above, were recruited to test their ability to use dry powder inhaler Handihaler® (Boeringher-Ingelheim) and Aerolizer® (Novartis). The results of a score created to evaluate the inhalation technique were compared with age, MMSE, Barthel Index, FEV1, maximum inspiratory and expiratory pressures, and peak inspiratory flow (PIF). ResultsDry powder inhalers were correctly used by 60% of the patients (15 out of 25). Among the capable ones, 13 out of 15 were aged less than 80 years (p≤0.02), 13 out of 15 had a maximum inspiratory pressure greater or equal to 53cm H2O (p≤0.001) and a PIF greater or equal to 120l/min (p≤0.05). All skilled patients had a minimum MMSE of 25 (p≤0.001). ConclusionIn a geriatric population, age, the decrease of maximum inspiratory pressure and PIF as well as cognitive functions, limit the use of dry powder inhalers.

Understanding inhalers, 2: Dry powder devices

In the second of two articles on how to help patients gain the benefits of inhaled therapy, Rachel Booker explains the principles for the use of dry powder inhalers

Use of dry powder inhalers in acute exacerbations of asthma and COPD

To investigate whether dry powder inhalers (DPIs) function in a constrained situation, a literature analysis was performed to evaluate the use of DPIs compared with established therapies in the treatment of acute asthma and COPD, irrespective of rapid-acting beta(2)-agonist used. The external databases Medline, Embase, Biosis and Current Contents and AstraZeneca's internal literature database Planet were searched up to April 2008. Only publications or congress abstracts describing clinical trials in patients treated at EDs or hospitals were considered, and then only those in which exacerbation severity (measured as FEV(1)) were included. Fifteen clinical studies met these criteria; twelve in acute asthma and three in acute COPD. For acute asthma, eight studies were double-blind, randomised studies (six in adults and two in children), two were open-label studies (one in adults and one in children), and two were investigational (methacholine challenge) studies. For the acute COPD studies, one was double-blind and randomised, one was single-blind and randomised, and one was open-label. This review found that administration of fast-acting bronchodilators via DPIs, the majority of which were Turbuhaler, is effective during an asthma or COPD worsening. Our literature review finds that DPIs function in patients with acute asthma or COPD equally well as established therapies with other inhaler devices. Patients can therefore rely upon DPIs in the same way that they rely upon other inhaler devices.

Pharmacokinetic, pharmacodynamic, efficacy, and safety data from two randomized, double-blind studies in patients with asthma and an in vitro study comparing two dry-powder inhalers delivering a combination of salmeterol 50 μg and fluticasone propionate 250 μg: Implications for establishing bioequivalence of inhaled products

Background: The use of dry-powder inhalers (DPIs) to administer respiratory medicines is increasing, and new DPIs are likely to be developed because of expiring patents. However, there is considerable debate concerning the extent to which DPIs are interchangeable without altering disease control or the safety profile of the treatment. Objective: This study was designed to compare the pharmacokinetic (PK), pharmacodynamic (PD), efficacy, and safety data for 2 DPIs delivering a combination of salmeterol 50 μg plus fluticasone propionate (FP) 250 μg (SFC 50/250) to investigate assumptions of bioequivalence. Methods: Three studies compared SFC 50/250 delivery using a reservoir powder inhalation device (RPID) and a Diskus® multiple-dose inhaler: an in vitro assessment of fine-particle-mass (FPM) profiles of the emitted doses; a PK/PD study of SFC 50/250 administered in two 14-day crossover treatment periods to 22 adults with moderate, persistent asthma to determine the equivalence of the RPID and Diskus inhaler in terms of drug delivery and systemic exposure; and a 12-week clinical efficacy and safety study of SFC 50/250 in 270 patients ≥12 years of age with moderate, persistent asthma to assess the equivalence of the RPID and Diskus inhaler based on peak expiratory flow (PEF) rates. FPM was summed from the quantity of active pharmaceutical ingredient deposited on stages 1 to 5 of a cascade impactor, representing an aerodynamic particle size range of 0.8 to 6.2 μm. Systemic exposure to SFC 50/250 was declared no greater with RPID than with the Diskus inhaler if the upper limit of the 90% CI for the ratio of FP AUC for the 2 devices was below the upper limit of the equivalence range (ie, <1.25). Adverse events, clinical laboratory test results, and vital signs were recorded throughout the 2 clinical studies. Results: In vitro, mean FPM values for the RPID and Diskus inhaler, respectively, were 13.1 and 12.8 μg/dose for salmeterol ( P = NS) and 66.8 and 66.2 μg/dose for FP ( P = NS). The only notable differences were mean FP for particle sizes 2.3 to 3.2 μm (21.4 μg/dose for RPID, 25.6 μg/dose for Diskus) and for sizes 4.0 to 6.2 μm (17.3 μg/dose for RPID, 11.7 μg/dose for Diskus). In the PK/PD study, there were 22 patients (16 men and 6 women), most (86%) of whom were white. Mean (SD) age was 26.0 (5.0) years (range, 19-35 years), and mean (SD) weight was 67.3 (8.9) kg. The 2 inhalers did not meet the criteria for declaring bioequivalence: estimated ratios (RPID:Diskus) were 2.00 (90% CI, 1.56 to 2.55) for FP AUC up to the time point of next dosing and 1.92 (90% CI, 1.64 to 2.25) for salmeterol maximum observed plasma concentration at the end of the dosing interval (at steady state). Urine cortisol (0–24 hours) was significantly lower for the RPID than for the Diskus inhaler (ratio, 0.74 [95% CI, 0.57 to 0.96]; P = 0.026); no significant difference in plasma cortisol was noted between the 2 inhalers (ratio, 0.85 [95% CI, 0.7 to 1.04]). A small but statistically significant increase in maximum heart rate (5 beats/min) was noted in the RPID group (ratio, 1.05 [95% CI, 1.01 to 1.10]; P = 0.029). No notable differences in other PD end points were observed. Drug-related adverse events occurred in both groups (2 [dysphagia and tremor] in the RPID group and 3 [2 cases of dysphonia, 1 case of mucous-membrane irritation] in the Diskus group). There were 270 patients (136 females, 134 males) in the clinical efficacy and safety study, most (94%) of whom were white; mean (SD) age was 37.2 (17.0) years (range, 11–77 years) in the RPID group and 35.4 (17.2) years (range, 12–77 years) in the Diskus group. The RPID and the Diskus inhaler met the predefined equivalence criteria (±15 L/min) in terms of mean change in morning PEF from baseline: 3.9 L/min (95% CI, -3.1 to 11.0). The 2 SFC 50/250 inhalers were well tolerated; the most frequently reported adverse event was bronchitis, reported by 12% of the patients in the RPID group and 9% of those in the Diskus group. The only serious adverse event, which occurred in the RPID group and was related to bronchial infection, was considered unrelated to treatment. Conclusions: In vitro particle size distribution data were potentially superimposable for the RPID and the Diskus inhaler. The 2 devices were considered to be clinically equivalent in terms of mean morning PEF but were not considered equivalent in terms of PK systemic exposure. The 2 SFC 50/250 inhalers were well tolerated and had comparable safety profiles; no serious adverse events were attributed to the study product.

Study on the Greek demographic chart of psychic disorders

Background: The use of dry-powder inhalers (DPIs) to administer respiratory medicines is increasing, and new DPIs are likely to be developed because of expiring patents. However, there is considerable debate concerning the extent to which DPIs are interchangeable without altering disease control or the safety profile of the treatment.Objective: This study was designed to compare the pharmacokinetic (PK), pharmacodynamic (PD), efficacy, and safety data for 2 DPIs delivering a combination of salmeterol 50 μg plus fluticasone propionate (FP) 250 μg (SFC 50/250) to investigate assumptions of bioequivalence.Methods: Three studies compared SFC 50/250 delivery using a reservoir powder inhalation device (RPID) and a Diskus® multiple-dose inhaler: an in vitro assessment of fine-particle-mass (FPM) profiles of the emitted doses; a PK/PD study of SFC 50/250 administered in two 14-day crossover treatment periods to 22 adults with moderate, persistent asthma to determine the equivalence of the RPID and Diskus inhaler in terms of drug delivery and systemic exposure; and a 12-week clinical efficacy and safety study of SFC 50/250 in 270 patients ≥12 years of age with moderate, persistent asthma to assess the equivalence of the RPID and Diskus inhaler based on peak expiratory flow (PEF) rates. FPM was summed from the quantity of active pharmaceutical ingredient deposited on stages 1 to 5 of a cascade impactor, representing an aerodynamic particle size range of 0.8 to 6.2 μm. Systemic exposure to SFC 50/250 was declared no greater with RPID than with the Diskus inhaler if the upper limit of the 90% CI for the ratio of FP AUC for the 2 devices was below the upper limit of the equivalence range (ie, <1.25). Adverse events, clinical laboratory test results, and vital signs were recorded throughout the 2 clinical studies.Results: In vitro, mean FPM values for the RPID and Diskus inhaler, respectively, were 13.1 and 12.8 μg/dose for salmeterol (P = NS) and 66.8 and 66.2 μg/dose for FP (P = NS). The only notable differences were mean FP for particle sizes 2.3 to 3.2 μm (21.4 μg/dose for RPID, 25.6 μg/dose for Diskus) and for sizes 4.0 to 6.2 μm (17.3 μg/dose for RPID, 11.7 μg/dose for Diskus). In the PK/PD study, there were 22 patients (16 men and 6 women), most (86%) of whom were white. Mean (SD) age was 26.0 (5.0) years (range, 19-35 years), and mean (SD) weight was 67.3 (8.9) kg. The 2 inhalers did not meet the criteria for declaring bioequivalence: estimated ratios (RPID:Diskus) were 2.00 (90% CI, 1.56 to 2.55) for FP AUC up to the time point of next dosing and 1.92 (90% CI, 1.64 to 2.25) for salmeterol maximum observed plasma concentration at the end of the dosing interval (at steady state). Urine cortisol (0–24 hours) was significantly lower for the RPID than for the Diskus inhaler (ratio, 0.74 [95% CI, 0.57 to 0.96]; P = 0.026); no significant difference in plasma cortisol was noted between the 2 inhalers (ratio, 0.85 [95% CI, 0.7 to 1.04]). A small but statistically significant increase in maximum heart rate (5 beats/min) was noted in the RPID group (ratio, 1.05 [95% CI, 1.01 to 1.10]; P = 0.029). No notable differences in other PD end points were observed. Drug-related adverse events occurred in both groups (2 [dysphagia and tremor] in the RPID group and 3 [2 cases of dysphonia, 1 case of mucous-membrane irritation] in the Diskus group). There were 270 patients (136 females, 134 males) in the clinical efficacy and safety study, most (94%) of whom were white; mean (SD) age was 37.2 (17.0) years (range, 11–77 years) in the RPID group and 35.4 (17.2) years (range, 12–77 years) in the Diskus group. The RPID and the Diskus inhaler met the predefined equivalence criteria (±15 L/min) in terms of mean change in morning PEF from baseline: 3.9 L/min (95% CI, -3.1 to 11.0). The 2 SFC 50/250 inhalers were well tolerated; the most frequently reported adverse event was bronchitis, reported by 12% of the patients in the RPID group and 9% of those in the Diskus group. The only serious adverse event, which occurred in the RPID group and was related to bronchial infection, was considered unrelated to treatment.Conclusions: In vitro particle size distribution data were potentially superimposable for the RPID and the Diskus inhaler. The 2 devices were considered to be clinically equivalent in terms of mean morning PEF but were not considered equivalent in terms of PK systemic exposure. The 2 SFC 50/250 inhalers were well tolerated and had comparable safety profiles; no serious adverse events were attributed to the study product.

Prospective, Randomized Cross-Over Trial to Assess the Ability of a Dry-Powder Inhaler to Reverse the Local Side Effects of Pressurized Metered-Dose Inhalers

Objectives. To determine whether a corticosteroid dry-powder inhaler could reverse the pharyngeal and laryngeal side effects produced by a corticosteroid pressurised metered-dose inhaler. Design. Prospective, randomized, controlled, cross-over, evaluator-blinded study. Setting. University Hospital Aintree, Liverpool, United Kingdom. Patients. Thirty-seven adults recruited over a 12-month period from Ear, Nose and Throat clinics at our University hospital. Patients were randomized into three groups using a computer-generated random number list and sealed opaque envelopes. Main outcome measures. Scores were achieved on respiratory symptom and vocal performance questionnaires. Acoustic analysis was performed followed by a standardized biopsy of the posterior pharyngeal wall. Histological markers of inflammation were correlated with pharyngitis. The data were tested for normality using the Kalmogorov-Smirnov test. The Kruskal-Wallis analysis of variance was used to investigate differences between medians and ranges. The data were further investigated for correlations using the Spearman test. Discriminant analysis was used to examine the effect of the three groups on each variable. Results. Discomfort scores (median and range) were significantly lower after dry-powder inhaler use than with either a spacer or water gargle (p < 0.01). These worsened after restoring pressurized metered-dose inhaler therapy. The reduction in pharyngitis in each of the three groups was not significant. Vocal performance scores improved with dry-powder inhaler use. Jitter, shimmer, and closed-phase quotient scores improved with dry-powder inhaler use (p < 0.01). Shimmer scores deteriorated once the pressurized metered-dose inhaler was restored (p < 0.01). There was no significant difference between the groups in most observed parameters of inflammation (p > 0.01). Conclusion. A dry-powder inhaler may alleviate the local side effects produced by a pressurized metered-dose inhaler. Laryngeal dysfunction appears to be particularly responsive to the absence of propellant. More observational and randomized controlled trials are necessary to examine existing inhalers and specifically, how and why they cause local side effects.

A Comparison of the Puncturing Properties of Gelatin and Hypromellose Capsules for Use in Dry Powder Inhalers

This study investigates capsule puncture in dry powder inhalers. Gelatin and hydroxypropylmethyl cellulose (HPMC) capsules (stored at 11 and 33% relative humidities) were punctured using a pin from a Foradil® inhaler, with insertion force measurement via an Instron tester. In HPMC capsules, the force after capsule puncture reduced by half and then increased to a second maximum as the pin shaft entered the hole. In gelatin capsules, the postpuncture force reduced to zero, indicating shell flaps losing contact with the pin. At lower moisture contents, both capsules were less flexible. This provides a tool to measure the shell properties of inhalation capsules.

Effect of incorrect use of dry powder inhalers on management of patients with asthma and COPD

Incorrect usage of inhaler devices might have a major influence on the clinical effectiveness of the delivered drug. This issue is poorly addressed in management guidelines. This article presents the results of a systematic literature review of studies evaluating incorrect use of established dry powder inhalers (DPIs) by patients with asthma or chronic obstructive pulmonary disease (COPD). Overall, we found that between 4% and 94% of patients, depending on the type of inhaler and method of assessment, do not use their inhalers correctly. The most common errors made included failure to exhale before actuation, failure to breath-hold after inhalation, incorrect positioning of the inhaler, incorrect rotation sequence, and failure to execute a forceful and deep inhalation. Inefficient DPI technique may lead to insufficient drug delivery and hence to insufficient lung deposition. As many as 25% of patients have never received verbal inhaler technique instruction, and for those that do, the quality and duration of instruction is not adequate and not reinforced by follow-up checks. This review demonstrates that incorrect DPI technique with established DPIs is common among patients with asthma and COPD, and suggests that poor inhalation technique has detrimental consequences for clinical efficacy. Regular assessment and reinforcement of correct inhalation technique are considered by health professionals and caregivers to be an essential component of successful asthma management. Improvement of asthma and COPD management could be achieved by new DPIs that are easy to use correctly and are forgiving of poor inhalation technique, thus ensuring more successful drug delivery.

Use of dry powder inhalers in COPD

This was a study of 30 chronic obstructive pulmonary disease (COPD) patients to assess the ease of use and preference of four dry powder inhalers -- accuhaler, aerolizer, handihaler, turbohaler -- the accuhaler and turbohaler are multidose devices, whereas the aerolizer and handihaler are single dose devices. None of the subjects had previous experience of dry powder inhalers. The correct technique for each inhaler was divided into 12 steps including one critical step that if not performed would result in no drug delivery. Subjects were shown the correct technique for each inhaler in a random order and were assessed immediately and 1 h later. Each subject was asked to rank the four devices for preference and ease of use, as well as to assess how comfortable it felt to inhale through the device using a visual analogue scale. The numbers of perfect scores were not significantly different between devices, but the number of fatal errors that would result in no drug delivery was significantly more common in single dose devices (p < 0.01). There were significant differences in the rankings of each device (Friedman test, p < 0.005) with the turbohaler being ranked first most often and the handihaler last. The turbohaler scored highest for comfort of inhalation and the accuhaler lowest, but differences were small. In COPD patients starting on dry powder inhalers, multidose devices appear to be preferred, have fewer problems and are easier to use effectively.

Zmienność szczytowego przepływu wdechowego (PIF) na zastawkach imitujących opory inhalatorów proszkowych w zaostrzeniu astmy i POChP

Drugs used in asthma or COPD exacerbation are delivered to the lungs by inhalation. This is facilitated, among other factors, by the use of dry powder inhalers (DPIs). Lung deposition from DPI depends predominantly on peak inspiratory flow (PIF). The aim of the study was to asses the variability of PIF generated by patients using different types of DPI inhalers during asthma or COPD exacerbation and to trace possible relationships between PIF value and some spirometric values. There were 28 patient fulfilling inclusion criteria, among them 17 (4 women) were suffering from COPD and 11 (8 women) from asthma. Spirometry, PEF and PIF measurements were performed in the first and the last day of hospitalisation. Peek inspiratory flow was obtained using In-Check DIAL - a device which simulated airflow resistances equivalent to Turbuhaler, Diskus and Aeroliser respectively. The significant improvement in PIF was observed only in patients with COPD. There were no statistically significant correlations between PIF and both FEV1 and PEF except those in the first day of hospitalization in COPD patients (r = 0.66-0.81). Optimal PIF was achieved in all patients only with Diskus. Measurements of peek inspiratory flow are useful in choosing the most suitable DPI for patients with COPD and asthma exacerbations. We conclude that in those patients, PIF measurement should complement a standard spirometry.

The Diskus: a review of its position among dry powder inhaler devices.

The use of dry powder inhalers (DPIs) to administer treatments for respiratory diseases has increased significantly in recent years. There is now a wide range of DPIs available that vary considerably in design, required operational techniques, output characteristics and drug delivery across a range of inhalation patterns. Different patient populations may find individual types of DPI easier to use correctly than others and selecting the right DPI for particular patient requirements will improve compliance with therapy. For example, some DPIs offer a greater resistance against inspirational flow rate than others which affects the total emitted dose and also fine particle mass of the aerosol released. An individual patient may therefore receive different amounts of drug when inhaling from different DPIs. Therefore, it is important that the prescriber is fully aware of the characteristics of the different types of DPI, so that he or she can prescribe the device that is most appropriate to an individual patient's needs. This review explores the characteristics of currently available DPIs and evaluates their efficacy and patient acceptability. The differences in output characteristics, ease of use and patient preferences between available devices is shown to affect treatment efficacy and patient compliance with therapy. Changing the DPI prescribed to a patient to a cheaper or generic device may therefore adversely affect disease control and thereby increase the cost of treatment.