Factors Determining In Vitro Lung Deposition of Albuterol Aerosol Delivered by Ventolin Metered-Dose Inhaler

The impact of actuator nozzle and surroundings condition on drug delivery using pressurized-metered dose inhalers

The most commonly used method to deliver aerosolized drugs to the lung is with pressurized metered-dose inhalers (pMDIs). The spray actuator is a critical component of pMDI, since it controls the atomization process by forming aerosol plumes and determining droplet size distribution. Through computational fluid dynamics (CFD) simulations, this study investigated the effect of two different nozzle types (single conventional and twin nozzles) on drug deposition in the mouth-throat (MT) region. We also studied the behavior of aerosol plumes in both an open-air environment and the MT geometry. Our study revealed that spray aerosol generated in an unconfined, open-air environment with no airflow behaves distinctly from spray introduced into the MT geometry in the presence of airflow. In addition, the actuator structure significantly impacts the device's efficacy. In the real MT model, we found that the twin nozzle increases drug deposition in the MT region, and its higher aerosol velocity negatively affects its efficiency.

Lower Inspiratory Breathing Depth Enhances Pulmonary Delivery Efficiency of ProAir Sprays

Effective pulmonary drug delivery using a metered-dose inhaler (MDI) requires a match between the MDI sprays, the patient’s breathing, and respiratory physiology. Different inhalers generate aerosols with distinct aerosol sizes and speeds, which require specific breathing coordination to achieve optimized delivery efficiency. Inability to perform the instructed breathing maneuver is one of the frequently reported issues during MDI applications; however, their effects on MDI dosimetry are unclear. The objective of this study is to systemically evaluate the effects of breathing depths on regional deposition in the respiratory tract using a ProAir-HFA inhaler. An integrated inhaler mouth-throat-lung geometry model was developed that extends to the ninth bifurcation (G9). Large-eddy simulation (LES) was used to compute the airflow dynamics due to concurrent inhalation and orifice flows. The discrete-phase Lagrangian model was used to track droplet motions. Experimental measurements of ProAir spray droplet sizes and speeds were used as initial and boundary conditions to develop the computational model for ProAir-pulmonary drug delivery. The time-varying spray plume from a ProAir-HFA inhaler into the open air was visualized using a high-speed imaging system and was further used to validate the computational model. The inhalation dosimetry of ProAir spray droplets in the respiratory tract was compared among five breathing depths on a regional, sub-regional, and local basis. The results show remarkable differences in airflow dynamics within the MDI mouthpiece and the droplet deposition distribution in the oral cavity. The inhalation depth had a positive relationship with the deposition in the mouth and a negative relationship with the deposition in the five lobes beyond G9 (small airways). The highest delivery efficiency to small airways was highest at 15 L/min and declined with an increasing inhalation depth. The drug loss inside the MDI was maximal at 45–60 L/min. Comparisons to previous experimental and numerical studies revealed a high dosimetry sensitivity to the inhaler type and patient breathing condition. Considering the appropriate inhalation waveform, spray actuation time, and spray properties (size and velocity) is essential to accurately predict inhalation dosimetry from MDIs. The results highlight the importance of personalized inhalation therapy to match the patient’s breathing patterns for optimal delivery efficiencies. Further complimentary in vitro or in vivo experiments are needed to validate the enhanced pulmonary delivery at 15 L/min.

Bioequivalence assessment of pharmaceutical aerosol products through IVIVC

Many pharmaceutical developers of generic orally inhaled products (OIPs) are facing significant issues in passing the regulatory requirement to show pharmacokinetic (PK) bioequivalence (BE) to the originator product. The core of the issue is that no reliable in vitro-in vivo correlation (IVIVC) is available to guide their development. In this paper, several issues are identified and means to improve the data used for developing an IVIVC are discussed. The article also presents an "IVIVC-free" approach for developing a formulation matching the originator's PK performance.

Status of inhalable antimicrobial agents for lung infection: progress and prospects

Introduction: Available parenteral and oral administration of antimicrobial agents (AMAs) in respiratory infections often show less penetration into the lung parenchyma. Due to inappropriate dose availability, the rate of antibiotic resistance is increasing gradually. Inhaled antibiotics intensely improve the availability of drugs at the site of respiratory infections. This targeted delivery minimizes systemic exposure and associated toxicity.Area covers: This review was performed by searching in the scientific database like PubMed and several trusted government sites like fda.gov, cdc.gov, ClinicalTrials.gov, etc. For better understanding, AMAs are classified in different stages of approval. Mechanism and characterization of pulmonary drug deposition section helps to understand the effective delivery of AMAs to the respiratory tract. There is a need for proper adoption of delivery devices for inhalable AMAs. Thus, delivery devices are extensively explained. Inspiratory flow has a remarkable impact on the delivery device that has been explained in detail.Expert opinion: Pulmonary delivery restricts the bulk administration of drugs in comparison with other routes. Therefore, novel AMAs with higher bactericidal activity at lower concentrations need to be synthesized. Extensive research is indeed in developing innovative delivery devices that would able to deliver higher doses of AMAs through the pulmonary route.

ATTACHED, DETACHED and WITHOUT inhaler technique coaching tools to optimize pMDI use competence, asthma control and quality-of-life in asthmatic adults

Background

Poor pressurized metered dose inhaler (pMDI) technique is prevalent, which will diminish treatment gains. In a two-visit study, two novel pMDI training devices with feedback mechanisms; Trainhaler (THR) and Flo-Tone CR (FTCR), were evaluated alongside the traditional verbal inhaler training (VT) in asthma outpatients.

Methods

On visit 1, 18-60 year-old asthmatics with incorrect pMDI use [including peak inhalation flow (PIF) >60 L/min] signed consent and baseline pMDI technique, lung function, asthma control and quality-of-life were measured. Participants were randomized to receive pMDI technique training using VT, THR or FTCR. One hour post-training, the pMDI coordination and PIF were re-assessed. The THR and FTCR patients were given their assigned tools to take home to facilitate regular training. All outcomes were re-evaluated 6-8 weeks later (visit 2).

Results

Ninety-two asthmatics completed visit 1 (46 attended visit 2). Pre-training, 61.3% (VT), 61.5% (THR) and 65.0% (FTCR) patients similarly made ≥2 pMDI errors with mean PIFs 175.2, 187.1 and 158.9 L/min, respectively. pMDI use was significantly improved 1 h post-training. The subjects that completed visit 2 had significantly, yet equally, maintained the improved inhaler use; only 28.0% (VT), 26.2% (THR) and 21.7% (FTCR) patients made ≥2 pMDI errors with PIF improvements; 115.3, 94.6 and 96.1 L/min, respectively. Clinical outcomes remained comparable.

Conclusions

VT improves the overall pMDI technique, however patients gradually forget their VT. The THR and FTCR devices are retained by the patients as their self-monitoring, all-time personal trainers that boost and maintain their VT between routine clinic visits.

Wrong inhalation technique is associated to poor asthma clinical outcomes. Is there room for improvement?

PURPOSE OF REVIEW

The long-term goals of asthma management are to control symptoms and to reduce the risk of exacerbations. Inhaled medication is the cornerstone of pharmacological treatment for asthma; therefore, good inhalation technique is the key for asthma management. However, up to 70% of asthma patients do not use their inhalers correctly. There is evidence on how poor inhalation technique is associated to poor asthma control. The purpose of this review is to present the most recent research in this field to help clinicians understand the importance of proper inhalers use and the possible interventions to optimize patients' inhalation technique.

RECENT FINDINGS

New evidence on how poor inhaler technique and specific critical errors are significantly associated to poor asthma control and exacerbations and how this negative impact could be improved by optimizing device selection, enhancing shared decision-making and giving more importance to education, both for patients and healthcare professionals. New devices and additional tools might help patients to achieve the correct inhaler technique and could form the basis of simplified educational interventions.

SUMMARY

There is an urgent need for specific interventions including new educational strategies to minimize the negative effects of wrong inhalation technique in asthma clinical outcomes.

The role of inspiratory flow in selection and use of inhaled therapy for patients with chronic obstructive pulmonary disease

Inhalation therapy is the mainstay of chronic obstructive pulmonary disease management, and inhaler selection can have a profound impact on drug delivery and medication adherence, as well as on treatment outcomes. Although multiple delivery systems, such as pressurized metered-dose inhalers, dry powder inhalers, slow-mist inhalers, and nebulizers, are available, clinical benefits achieved by patients rely on effective delivery of the inhaled medication to the airways. Among several factors influencing drug deposition, inspiratory flow is one of the most important. Inspiratory flow impacts drug delivery and subsequent clinical efficacy, making it necessary to adequately train patients to ensure correct inhaler use. Peak inspiratory flow is the maximal airflow generated during a forced inspiratory maneuver. Health care professionals need to select the appropriate delivery system after carefully considering patient characteristics, including lung function, optimal inspiratory flow, manual dexterity, and cognitive function. Herein, the role of inspiratory flow in the selection and use of inhaled therapy in patients with COPD is reviewed.

Delivered Lung Dose and Aerodynamic Particle Size Distribution of Salbutamol Pressurized Metered Dose Inhaler After Living Under Patients' Realistic Retention Environments

Background: The impact of inhalers' postdispensing, real-life temperature and relative humidity (RH) environments on their delivered dose (DD) and aerodynamic particle size distribution (APSD) is usually overlooked. This work evaluated the salbutamol DD and APSD of Ventolin^® Evohaler^® (V) inhalers already been used and stored by respiratory patients. Methods: Adult patients, prescribed V for ≥3 months before study enrollment, were dispensed both new V to use and portable, handheld electronic temperature and RH data loggers to keep close to the given V before returning them both after 2-3 weeks. Patients' enrollment took place during summer (VS) and winter (VW) seasons. The returned V was then in vitro evaluated using the Next Generation Impactor, and compared with control V (VC) counterparts stored under 21°C and 46% RH. Results: The VS survived in fluctuating habitats of 21.2°C-40.4°C and 16.2%-63.2% RH, which significantly (p < 0.05) decreased the salbutamol DD from 80.4 to 70.5 μg compared with VC. This 12.3% DD reduction was accompanied with a decrease in the fine particle dose from 26.2 to 20.4 μg (p < 0.05), and an increase in the mass median aerodynamic diameter from 2.3 to 2.5 μm (p < 0.05). The VW and VC had equivalent DD and APSD. Conclusion: Patients using V are expected to receive smaller lung doses during the hot summer season compared with intentionally well-kept VC. To have equivalent lung deposition, V users should be advised to retain their inhalers around 20°C with minimal daily environmental fluctuations during summer times.

Characterization and comparison of Re-Du-Ning aerosol particles generated by different jet nebulizers

Inhalation therapy is the first-line therapy for the treatment of respiratory diseases. Re-Du-Ning inhalation solution (RIS) is an aerosol derivative from the Re-Du-Ning injection and has been clinically used to treat respiratory diseases like pneumonia for more than twenty years in China. However, the aerosolization and inhalation performances of RIS using different nebulizers have not been characterized, which may affect the therapeutic effects of RIS on respiratory diseases. We investigated the inhalation performances of RIS using five different nebulizers utilizing Spraytec, breath simulator of BRS 2000 and NGI techniques. We tested 5 different types of jet nebulizer, using RIS and an adult breathing pattern, to determine the difference in aerosol delivery over time. The particle size distribution of RIS was monitored by a Spraytec laser particle sizer. Fine particle fraction (FPF) and mass median aerodynamic diameter (MMAD) for RIS were measured using NGI. Aerosol deposited on the filter was analysed using HPLC. Nebulization time was much longer for the Pari Boy SX (red) nebulizer than for the other nebulizers, with the minimum delivery rate (DR) and the maximum total delivered dose (TDD) and total exhalation dose (TED). Nebulization time for Pari Boy SX (blue) was the lowest, with the highest DR and the lowest TDD and TED. Furthermore, the aerodynamic particle size of RIS was much larger for the Pari blue and Pari LC Plus than other nebulizers. Pari red produced the smallest aerodynamic particle size of RIS in these five nebulizers. In addition, a good linear relationship was found between MMAD and D₅₀ in these five nebulizers. The results demonstrated that Pari Boy SX (red) delivered most slowly and produced the smallest aerodynamic particle size of the RIS aerosols, which may be applied to manage lower respiratory diseases. Moreover, Pari LC Plus and Pari Boy SX (blue) emitted quickly and generated larger aerodynamic particle size of RIS aerosols, which could be used to treat upper respiratory diseases. A good linear relationship between MMAD and D₅₀ showed Spraytec could be a reliable technique for the development, evaluation and quality control of aerosol particles of inhalation solution preparations.

Delivery dose uniformity determination by BRS 2000 breath simulator and realtime particle size distribution monitoring by Spraytec.

Effect of delayed pMDI actuation on the lung deposition of a fixed-dose combination aerosol drug

Lack of coordination between the beginning of the inhalation and device triggering is one of the most frequent errors reported in connection with the use of pMDI devices. Earlier results suggested a significant loss in lung deposition as a consequence of late actuation. However, most of our knowledge on the effect of poor synchronization is based on earlier works on CFC devices emitting large particles with high initial velocities. The aim of this study was to apply numerical techniques to analyse the effect of late device actuation on the lung dose of a HFA pMDI drug emitting high fraction of extrafine particles used in current asthma and COPD therapy. A computational fluid and particle dynamics model was combined with stochastic whole lung model to quantify the amount of drug depositing in the extrathoracic airways and in the lungs. High speed camera measurements were also performed to characterize the emitted spray plume. Our results have shown that for the studied pMDI drug late actuation leads to reasonable loss in terms of lung dose, unless it happens in the second half of the inhalation period. Device actuation at the middle of the inhalation caused less than 25% lung dose reduction relative to the value characterizing perfect coordination, if the inhalation time was between 2 and 5 s and inhalation flow rate between 30 and 150 L/min. This dose loss is lower than the previously known values of CFC devices and further support the practice of triggering the device shortly after the beginning of the inhalation instead of forcing a perfect synchronization and risking mishandling and poor drug deposition.

Inhalation device options for the management of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by chronic respiratory symptoms and airflow limitation, resulting from abnormalities in the airway and/or damage to the alveoli. Primary care physicians manage the healthcare of a large proportion of patients with COPD. In addition to determining the most appropriate medication regimen, which usually includes inhaled bronchodilators with or without inhaled corticosteroids, physicians are charged with optimizing inhalation device selection to facilitate effective drug delivery and patient adherence. The large variety of inhalation devices currently available present numerous challenges for physicians that include: (1) gaining knowledge of and proficiency with operating different device classes; (2) identifying the most appropriate inhalation device for the patient; and (3) providing the necessary education and training for patients on device use. This review provides an overview of the inhalation device types currently available in the United States for delivery of COPD medications, including information on their successful operation and respective advantages and disadvantages, factors to consider in matching a device to an individual patient, the need for device training for patients and physicians, and guidance for improving treatment adherence. Finally, the review will discuss established and novel tools and technology that may aid physicians in improving education and promoting better adherence to therapy.