Drug delivery to the lungs from dry powder inhalers

Correlation between Hand Grip Strength and Peak Inspiratory Flow Rate in Patients with Stable Chronic Obstructive Pulmonary Disease

Optimal peak inspiratory flow rate (PIFR) is required for effective drug delivery to distal airways when using dry powder inhalers (DPIs). This study aimed to examine the association between PIFR and hand grip strength (HGS) in stable COPD patients. A cross-sectional study was conducted. PIFR was measured using the In-check DIAL to assess for Accuhaler and Turbuhaler DPIs. HGS was measured using a handheld dynamometer. A PIFR of <60 L/min was considered suboptimal PIFR. Demographics, clinical data, and spirometric data were collected and compared. Eighty-one patients (86% men) were included. Mean age was 73.3 ± 8.9 years. FEV1 was 65.3 ± 23.7%. The prevalence of suboptimal PIFR was 38% and 59% for Accuhaler and Turbuhaler, respectively. HGS in the suboptimal PIFR group was lower than in the optimal PIFR group for Accuhaler (22.8 ± 4.7 vs. 33.2 ± 6.9 kg, p < 0.001) and for Turbuhaler (25.3 ± 6.4 vs. 35.1 ± 6.3 kg, p < 0.001). The equation for predicted Accuhaler PIFR (L/min) was −30.340 + (0.274 × hand grip strength) − (0.206 × age) + (0.219 × height) + (1.019 × FVC). The equation for predicted Turbuhaler PIFR (L/min) was 56.196 + (0.321 × hand grip strength) − (0.196 × female) − (0.224 × age) + (0.304 × FVC). The best cutoff values of HGS for predicting optimal PIFR in Accuhaler and Turbuhaler were 26.8 kg (with 82% sensitivity and 84% specificity) and 31.9 kg (with 79% sensitivity and 90% specificity), respectively. In conclusion, HGS correlated with PIFR in patients with clinically stable COPD, especially in the group with pronounced symptoms without frequent exacerbations. HGS threshold values associated with suboptimal PIFR were identified. HGS may be used as an alternative tool to assess an optimal inspiratory force for DPIs.

Optimizing inhalation therapy in the aspect of peak inhalation flow rate in patients with chronic obstructive pulmonary disease or asthma

BACKGROUND

Pressurized metered dose inhalers (pMDIs) and dry powder inhalers (DPIs) are commonly used drug-delivering devices for patients with chronic airway diseases. Appropriate peak inhalation flow rate (PIFR) and inhaler technique is essential for effective therapy. We aimed at optimizing inhalation therapy through the analysis of PIFRs in patients with chronic obstructive pulmonary disease (COPD) or asthma as well as the effect of technique training using In-Check DIAL® to help patients to achieve their optimal inspiratory flow rates.

METHODS

The study continuously enrolled patients who were diagnosed as COPD or asthma from respiratory clinics. PIFRs were described and analyzed between the newly-diagnosed and follow-up patients, and the stable and acute exacerbation patients, respectively. Every participant was trained inhaler technique using In-Check DIAL®. PIFRs before and after training was compared by self-control analysis.

RESULTS

Among a total of 209 patients, the average age was 56.9 years. For DPIs users, 10.8% patients had a PIFR < 30 L/min and 44.1% patients had a PIFR ≥ 60 L/min before technique training. After technique training, scarcely patient (1.5%) had a PIFR < 30 L/min, and 60.5% patients had a PIFR ≥ 60 L/min. The patient's average PIFR increased by 5.6L/min after training. The increase in PIFR before and after training was significant (p < 0.001) for most patients, but no significant variation was found in patients with acute exacerbation (p = 0.822).

CONCLUSIONS

A considerable number of patients with COPD or asthma were not able to achieve the minimum or optimal PIFR for DPIs. Inhaler training can increase patients' PIFRs and improve their ability to use DPIs. Trail registration The study has registered in chictr.org.cn (ChiCTR1900024707) and been approved by the Ethics Committee of Zhongshan Hospital of Fudan University (B2019-142).

Humidified and Heated Cascade Impactor for Aerosol Sizing

Aerosol sizing is generally measured at ambient air but human airways have different temperature (37°C) and relative humidity (100%) which can affect particle size in airways and consequently deposition prediction. This work aimed to develop and evaluate a new method using cascade impactor to measure particle size at human physiological temperature and humidity (HPTH) taking into account ambient air conditions. A heated and humidified trachea was built and a cascade impactor was heated to 37°C and humidified inside. Four medical aerosols [jet nebulizer, mesh nebulizer, Presurized Metered Dose Inhaler (pMDI), and Dry Powder Inhaler (DPI)] under ambient conditions and at HPTH were tested. MMAD was lower at HPTH for the two nebulizers; it was similar at ambient conditions and HPTH for pMDI, and the mass of particles smaller than 5 μm decreased for DPI at HPTH (51.9 vs. 82.8 μg/puff). In conclusion, we developed a new method to measure particle size at HPTH affecting deposition prediction with relevance. In vivo studies are required to evaluate the interest of this new model to improve the precision of deposition prediction.

Association between peak inspiratory flow rate and hand grip muscle strength in hospitalized patients with acute exacerbation of chronic obstructive pulmonary disease

RATIONALE

Ineffective peak inspiratory flow rate (PIFR) generation in patients using inhalers results in insufficient drug delivery to the lungs and poor clinical outcomes. Low inspiratory muscle strength is associated with suboptimal PIFR.

OBJECTIVE

To examine in a prospective study the relationship between PIFR and skeletal muscle strength using hand grip strength (HGS) as a surrogate.

METHODS

Adult patients admitted with acute exacerbation of chronic obstructive pulmonary disease (COPD) were enrolled. PIFR was measured within 48 hours before discharge. PIFR below 60L/min was considered suboptimal. HGS was measured using a handheld dynamometer. Any readmissions and emergency department visit data were collected. The associations between PIFR, HGS, 30 and 90-day COPD and all-cause readmissions were examined, without and with adjustment for age, race and gender.

RESULTS

Of the 75 enrolled patients, 56% had suboptimal PIFR; they were older (63.9±9.7 vs. 58.2±7.7 years) and had significantly lower HGS (24.2±11.1 vs. 30.9±10.9 Kg) compared to those with optimal PIFR. There were no significant differences between the two PIFR groups by gender, race, history of coronary artery disease, congestive heart failure, hypertension or functional scores. Each kilogram increase in HGS was associated with 0.50 (95%CI 0.18-0.89, p = 0.003) L/min increase in PIFR. We did not observe an association between PIFR and 30 or 90-day readmission rates.

CONCLUSION

We found a significant association between HGS and PIFR in hospitalized patients with acute exacerbations of COPD. Whether interventions aimed at increasing skeletal muscle strength also result in improvement in PIFR remains unclear and need further study.

Prevalence of Low Peak Inspiratory Flow Rate at Discharge in Patients Hospitalized for COPD Exacerbation

Background: Low peak inspiratory flow rate (PIFR) (<60 L/min) among patients with chronic obstructive pulmonary disease (COPD) may result in ineffective medication inhalation, leading to poor bronchodilation. Objective: The objectives of this analysis were to evaluate the prevalence of low PIFR at the time of discharge from a COPD-related hospitalization and to examine the real-world treatment patterns and rehospitalizations by PIFR. Methods: Patients at 7 sites in the United States were screened for enrollment at hospital discharge. PIFR was measured using the InCheck^TM DIAL to simulate resistance of the DISKUS® dry powder inhaler (DPI). An equal number of patients were enrolled into low PIFR (<60 L/min) or normal PIFR (≥60 L/min) cohorts. Demographics, COPD-related clinical characteristics, health status, treatment and rehospitalization data were collected. Results: Mean PIFR was 71±22.12 L/min among 268 screened patients; 31.7% (n=85) of patients had low PIFR. Among all enrolled patients (n=170), the low PIFR cohort was older (66.2±10.04 years versus 62.1±9.41 years, p=0.006) and more likely to be female (61.2% versus 42.4%, p=0.014). There was an increase in DPI use at discharge, compared with admission, in the low PIFR cohort (62.4% versus 70.6%, p=0.020). The incidences of all-cause rehospitalization up to 180 days were similar between the low and normal PIFR cohorts. Conclusions: At discharge following hospitalization for an exacerbation of COPD, approximately one-third of patients had a PIFR <60 L/min. More patients with a low PIFR were discharged with a DPI medication compared with use at admission. There was no difference in the rehospitalization rates by PIFR.

Pure insulin nanoparticle agglomerates for pulmonary delivery

Diabetes is a set of diseases characterized by defects in insulin utilization, either through autoimmune destruction of insulin-producing cells (Type I) or insulin resistance (Type II). Treatment options can include regular injections of insulin, which can be painful and inconvenient, often leading to low patient compliance. To overcome this problem, novel formulations of insulin are being investigated, such as inhaled aerosols. Sufficient deposition of powder in the peripheral lung to maximize systemic absorption requires precise control over particle size and density, with particles between 1 and 5 microm in aerodynamic diameter being within the respirable range. Insulin nanoparticles were produced by titrating insulin dissolved at low pH up to the pI of the native protein, and were then further processed into microparticles using solvent displacement. Particle size, crystallinity, dissolution properties, structural stability, and bulk powder density were characterized. We have demonstrated that pure drug insulin microparticles can be produced from nanosuspensions with minimal processing steps without excipients, and with suitable properties for deposition in the peripheral lung.

Poly(D,L-lactide-co-glycolide) nanoparticle agglomerates as carriers in dry powder aerosol formulation of proteins

A dry powder aerosol drug delivery system was designed with both nano- and microstructure to maximize the protein loading via surface adsorption and to facilitate delivery to the deep lung, respectively. Ovalbumin was employed as a model protein to adsorb to and controllably flocculate DOTAP-coated PLG nanoparticles into "nanoclusters" possessing low density microstructure. The mechanism of nanoparticle flocculation was probed by evaluating the effects of ionic strength, shear force, and protein concentration on the geometric and aerodynamic diameters of the nanoclusters as well as the protein adsorption efficiency. Salt ions were found to compete with ovalbumin adsorption to nanoparticles and facilitate flocculation; therefore, formulation of nanoclusters for inhaled drug delivery may require the lowest possible ionic strength to maximize protein adsorption. Additional factors, such as shear force and total protein-particle concentration can be altered to optimize nanocluster size, suggesting the possibility of regional lung delivery. Immediate release of ovalbumin was observed, and native protein structure upon release was confirmed by circular dichroism and fluorescence spectroscopy studies. Controlled flocculation of nanoparticles may provide a useful alternative to spray drying when formulating dry powders for pulmonary or nasal administration of protein therapeutics or antigens.

Advanced formulation design: improving drug therapies for the management of severe and chronic pain

Chronic pain is a condition affecting a vast patient population and resulting in billions of dollars in associated health care costs annually. Sufferers from severe chronic pain often require [correction of requite] twenty-four hour drug treatment through intrusive means and/or repeated oral dosing. Although the oral route of administration is most preferred, conventional immediate release oral dosage forms lead to inconvenient and suboptimal drug therapies for the treatment of chronic pain. Effective drug therapies for the management of chronic pain therefore require advanced formulation design to optimize the delivery of potent analgesic agents. Ideally, these advanced delivery systems provide efficacious pain therapy with minimal side effects via a simple and convenient dosing regime. In this article, currently commercialized and developing drug products for pain management are reviewed with respect to dosage form design as well as clinical efficacy. The drug delivery systems reviewed herein represent advanced formulation designs that are substantially improving analgesic drug therapies.

Variability of fine particle dose and lung deposition of budesonide delivered through two multidose dry powder inhalers

OBJECTIVE

To assess the reliability of dosing through two budesonide multidose dry powder inhalers (DPI) as derived from the in-vitro variability of the fine particle dose (FPD) and the in-vivo variability of the lung deposition at different flow rates.

METHODS

The same two DPIs [device N (Novolizer) and device T (Turbuhaler)] were compared in both studies. In the in-vitro study, the variability of the FPD, measured at flow rates of 30-100 L/min, was determined for equal flow rates and at comparable maximal inspiratory pressures (MIP). In the in-vivo study in healthy subjects (scintigraphic, randomised, crossover design) the variability of the lung deposition was determined at targeted flow rates of 45, 60 and 90 L/min for device N, and at 60 L/min for device T.

RESULTS

The variability of the FPD was lower with device N than with device T by 34%-86%. The differences were statistically significant for flow rates of 60, 70, 90 and 100 L/min (not significant for 40, 50 and 80 L/min) in the in-vitro study. Results for comparable MIPs showed analogous differences (79%, p = 0.004, at the clinically relevant MIP of 4.5 kPa). The variability of the lung deposition was clearly lower with the device N than with the device T. The difference was statistically significant (p = 0.029) at a comparable targeted flow rate of 60 L/min.

CONCLUSIONS

Thus, this study showed that device N is likely to improve the reliability of inhalation therapy by reducing both the variability of the delivered drug and that of the lung deposition. The reliability of inhalation therapy and consequently the quality of long-term control of asthma and the patient's compliance might improve when choosing the DPI with the better characteristics.

Novolizer: a multidose dry powder inhaler

Novolizer is a multidose breath-actuated dry powder inhaler (DPI) approved for use with salbutamol (albuterol) and budesonide. It has multiple patient feedback mechanisms and an inspiratory flow rate threshold designed to optimise dosage. In two studies, children aged 4-11 years with asthma correctly used Novolizer and generated mean peak inspiratory flow rates (PIFRs) through Novolizer of 76 and 92.7 L/min, well above the Novolizer threshold of 35-50 L/min. In healthy volunteers, median lung deposition of budesonide administered via Novolizer was 19.9-32.1% at mean PIFRs of 54-99 L/min. In a randomised, double-blind, single-dose study in patients with chronic obstructive pulmonary disease (COPD) and asthma, the 1-hour improvement from baseline in mean maximum forced expiratory volume in 1 second (FEV(1)) was 21.3% with inhalation of salbutamol through Novolizer, and 19.5% through Sultanol pressurised metered-dose inhaler (MDI). FEV(1) increased significantly in patients with asthma and COPD treated for 4 weeks in a randomised, open-label comparison of salbutamol through either Novolizer or Sultanol MDI. A randomised open-label study in adults with asthma treated with inhaled budesonide found equivalent improvements in FEV(1) and symptoms with Novolizer and Turbuhaler. Novolizer was well accepted overall. Most patients preferred it to previously used MDIs or DPIs. Only 4-5% found the taste feedback unacceptable. Physicians observed improved compliance over 4 weeks in 80% of patients with asthma using Novolizer.