Appropriate use of a dry powder inhaler based on inhalation flow pattern

Assessing the effectiveness of inhalation therapy in patients with chronic airway diseases: A new digital measurement

BACKGROUND

This study aimed to evaluate the effectiveness of inhalation therapy in patients with chronic airway diseases via the use of a new multiparametric inhalation assessment device.

METHODS

A multiparametric inhalation evaluation device (PF810, UBREATH, Zhejiang, China) that could simulate common inhalation devices with 6 different levels (0-V) of resistance was used in this study. The device was considered suitable if the three parameters of peak inspiratory flow rate (PIFR), effective inspiratory time (EIT), and breath-hold time (BHT) after inspiration met the minimum requirements.

RESULTS

A total of 4,559 tests were performed. The qualification rates of 0-V resistance gear from low to high were 3.38 % (I), 8.42 % (0), 15.31 % (II), 16.71 % (III), 20.27 % (IV), and 46.91 % (V). The COPD patients in the 3 experimental groups had the lowest percentages of isolates classified as resistant 0, III, and V, which were 5.65 %, 11.93 %, and 40.43 %, respectively. The lowest percentage was 39.67 % (V) for insufficient EIT and 18.40 % (V) for BHT less than 5 s after inspiration. The results of 149 subjects who had used the inhalation device showed that the VIE and EIT at 0 levels were significantly greater than those before training (Z= -5.651, -5.646, P < 0.001). The VIE and EIT at I-III and V significantly increased after training (all P < 0.05).

CONCLUSIONS

Patients using portable inhaler devices do not always inhale with adequate flow patterns. The multiparametric inhalation assessment device may be useful in outpatient settings.

Exploration of quality criteria for the detection of peak inspiratory flow under different resistance conditions

BACKGROUND

At present, robust quality criteria and methods for the assessment of Peak inspiratory flow meter performance are lacking.

OBJECTIVE

A standard flow-volume simulator for quality control analyses of an inhalation assessment device was utilized with different simulated resistance levels in order to propose a quality testing method and associated standard for this device type.

METHODS

A standard flow-volume simulator was utilized to assess the performance of an In-Check DIAL® (Device I) and an intelligent inhalation assessment device (Device P) at a fixed volume and flow rate. Indices used to evaluate these two instruments included repeatability, accuracy, linearity, and impedance.

RESULTS

Both devices exhibited good repeatability (<± 3 L/min). The difference between test results and standard simulator values for Device P was less than ± 5 L/min at resistance level R1 but higher than ± 5 L/min at resistance levels R2-5, while Device I were greater than 5 L/min at all resistance levels. The relative error for Device P was <± 10% at resistance levels R1, R2, and R4, but > 10% at resistance levels R3 and R5. The relative error values for Device I at all five resistance levels were > 10%. Device P passed the linearity test at the R2 resistance level, while Device I partially passed the linearity test at all five resistance levels.

CONCLUSION

Standard monitoring methods and standards provide a valuable approach to the more reliable clinical assessment and application of these instruments.

In Vitro Comparison of Two Blister-Type Inhalers

BACKGROUND

Ellipta is a respiratory device that is a successor of the Diskus. A major difference between the devices is that Ellipta, especially the 2-strip type, includes a pair of blisters rather than a single blister as contained in Diskus. This study aimed to compare the particle-release properties and mechanical features of both devices.

METHODS

A pump was used to evacuate air from each dry powder inhaler (DPI) with either a ramp-up or triangular pattern. The particle release volume and peak inspiratory flow of the DPIs were compared. Then the resistance of each component was measured.

RESULTS

Both DPIs required specific threshold flows for particle release. Inspiratory flows exceeding the threshold values (Ellipta 11.3 ± 4.0 L/min and Diskus 29.7 ± 4.7 L/min using ramp-up inhalations; Ellipta 10.6 ± 2.1 L/min and Diskus 28.4 ± 5.2 L/min using triangular ones) did not further increase particle release volumes. The inspiratory flows required for Ellipta were significantly less than those for Diskus. The particle release volume exceeding threshold flow for Ellipta was approximately 2.62 (ramp-up) and 2.01 (triangular) times those of Diskus. The resistance of one blister was similar (0.44 cm H2O/L/min vs 0.42 cm H2O/L/min for Ellipta and Diskus, respectively). As Ellipta includes 2 parallel blisters, similar resistances suggest that Ellipta requires twice the flow of Diskus. The flow distributions for particle release in Ellipta and Diskus were 35.3 and 5.2% of the total inspiratory flow, respectively.

CONCLUSIONS

The Ellipta required lower inspiratory flow than Diskus, which arises from a higher distribution to blister flow. Ellipta may be preferable to Diskus for patients with impaired pulmonary function.

Formulation, Device, and Clinical Factors Influencing the Targeted Delivery of COVID-19 Vaccines to the Lungs

The COVID-19 pandemic has proven to be an unprecedented health crisis in the human history with more than 5 million deaths worldwide caused to the SARS-CoV-2 and its variants ( https://www.who.int/emergencies/diseases/novel-coronavirus-2019 ). The currently authorized lipid nanoparticle (LNP)-encapsulated mRNA vaccines have been shown to have more than 90% vaccine efficacy at preventing COVID-19 illness (Baden et al. New England J Med 384(5):403-416, 2021; Thomas et al., 2021). In addition to vaccines, other small molecules belonging to the class of anti-viral and anti-inflammatory compounds have also been prescribed to reduce the viral proliferation and the associated cytokine storm. These anti-viral and anti-inflammatory compounds have also been shown to be effective in reducing COVID-19 exacerbations especially in reducing the host inflammatory response to SARS-CoV-2. However, all of the currently FDA-authorized vaccines for COVID-19 are meant for intramuscular injection directly into the systemic circulation. Also, most of the small molecules investigated for their anti-COVID-19 efficacy have also been explored using the intravenous route with a few of them explored for the inhalation route (Ramakrishnan et al. Lancet Respir Med 9:763-772, 2021; Horby et al. N Engl J Med 384(8):693-704, 2021). The fact that the SARS-CoV-2 enters the human body mainly via the nasal and airway route resulting in the lungs being the primary organs of infection as characterized by acute respiratory distress syndrome (ARDS)-mediated cytokine storm in the alveolar region has made the inhalation route gain significant attention for the purposes of targeting both vaccines and small molecules to the lungs (Mitchell et al., J Aerosol Med Pulm Drug Deliv 33(4):235-8, 2020). While there have been many studies reporting the safety and efficacy of targeting various therapeutics to the lungs to treat COVID-19, there is still a need to match the choice of inhalation formulation and the delivery device platform itself with the patient-related factors like breathing pattern and respiratory rate as seen in a clinical setting. In that perspective, this review aims to describe the various formulation and patient-related clinical factors that can play an important role in the judicious choice of the inhalation delivery platforms or devices for the development of inhaled COVID-19 vaccines.

Optimal Inhalation Flow Pattern from Turbuhaler Predicted by Laser Photometry

Background: The emitted dose (ED) from most dry powder inhalers (DPIs) is almost independent of peak inspiratory flow (PIF) above a certain value, which is specific to the individual DPI. However, the ED of the Turbuhaler^® (TBH) increases linearly with PIF increments. This study investigated the powder clearance and clinical utility of TBH performance features by using the photo-reflection method (PRM), a type of laser photometry. Methods: Pulmicort^® (PLM) (containing budesonide only) and Symbicort^® (SMB) (drugs with lactose particles) were inspired with a ramp-up pattern of several PIF intensities using a vacuum pump. Time trajectories of particle release and PIF were then compared. Results: The particle-release trajectories from both types of DPIs were similar, consisting of a sharp increment phase (∼0.15 seconds) followed by exponential decay. Both onset to the peak of particle-release time and particle-release times were not affected by PIF changes when the PIF was >40 L/min. EDs from both TBHs were linearly related to PIFs, and the slope of the regression equation for SMB was 2.4-fold larger than that of PLM. The peak of the released particles (PK_IED) was also linearly related to PIF. A linear relationship was also observed between ED and PK_IED in both TBHs, and these regression lines overlapped. Conclusion: EDs from the TBH were dependent on PK_IED. Therefore, rapid, initially strong, and deep inhalation should be advised while using the TBH. PRM could measure the fine and small amount of particles released from the TBH.

Peak inspiratory flow in children and adolescents with asthma using dry powder inhalers: a cross-sectional study

Objective:

To measure peak inspiratory flow (PIF) and assess dynamic lung function in children and adolescents with asthma, as well as to determine the association of PIF with dynamic lung function and clinical variables.

Methods:

This was a cross-sectional study of children and adolescents with asthma using dry powder inhalers (DPIs) regularly. The control group included sex-, age-, weight-, and height-matched individuals without lung disease. Socioeconomic and clinical variables were collected. PIF and dynamic lung function variables were obtained with a specific device. Between-group comparisons were made with the Student’s t-test and ANOVA. Multiple linear regression analysis was performed, and Pearson’s correlation coefficients were calculated to assess associations between PIF and the other variables.

Results:

A total of 88 individuals (44 asthma patients and 44 controls) participated in the study. PIF and respiratory muscle strength (S-index) values were lower in the asthma patients than in the controls. PIF correlated positively with age, weight, height, and S-index in the asthma group. After controlling for height, we found an increase of 0.05 units in PIF associated with an increase of 1 unit in the S-index in the asthma group.

Conclusions:

PIF appears to be lower in children and adolescents with asthma than in those without asthma, correlating positively with age, height, weight, and respiratory muscle strength.

Correcting Photo Reflection Method Output and Its Application in the Dynamic Analysis of Particle Release from Dry Powder Inhalers

Background: The photo reflection method (PRM) is used to measure light reflected from particles released from dry powder inhalers (DPIs). This simple method depicts time trajectories of released drugs; however, it underestimates the number of particles at high peak inhalation flow rates (PIFs). In this study, we aimed to correct this underestimation and clarify whether long inhalation is necessary for capsule-type DPIs, using this unique method. Methods: To establish quantitative measurements using the PRM, several types of DPIs were inhaled with square-wave inhalations at different PIFs using an inhalation simulator, and the total emitted dose (TED) and the release time of the TED (T_TED) were measured. Next, capsule-type DPIs were inhaled using inhalation patterns of patients with chronic obstructive pulmonary disease (COPD), and particle release time trajectories were recorded. Results: For all DPIs, except for Turbuhaler^® (TBH), both TED and T_TED were hyperbolically decreased with an increase in the PIF of square-wave inhalations. TED correction using the T_TED showed flat TED changes at high PIF ranges. The patient inhalation analysis showed that the corrected TEDs of seven COPD inhalation patterns were not significantly different. The PRM further revealed that the inhaled flow rate and release time of all seven patterns were sufficient to release particles in the capsule. Conclusions: The inhaled flow rate and T_TED that exceeded specific conditions enabled complete particle release from the DPIs except for TBH. Therefore, an extremely long inhalation is not required for capsule-type DPIs. Our corrected time trajectory analysis using the PRM provides a new strategy for the particle release analysis of DPIs.