Inspiratory Flow Rates through a Novel Dry Powder Inhaler (Clickhaler) in Pediatric Patients with Asthma

Nantel, Normand P.; Newhouse, Michael T.

doi:10.1089/jam.1999.12.55

Cited by 13 publications

(6 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Engel's group was unable to predict PIF based on any of the measures of expiratory flow. Nantel and Newhouse 13 did not find any correlation between PIF and age or FEV 1 % predicted in their study of stable asthmatic children aged 7−16 years. This lack of association may have been due to the small sample ( n = 17) or because the added resistance of the Turbuhaler alters the association in a non‐linear fashion.…”

Section: Discussionmentioning

confidence: 75%

Peak inspiratory flows in children with cystic fibrosis

Gauld

Briggs

Robinson

2003

J Paediatrics Child Health

View full text Add to dashboard Cite

In children with significant cystic fibrosis lung disease, peak inspiratory flow is likely to be > 0.5 L/s, which is required to activate dry powder inhalers. If the forced vital capacity is < 2.5 L, the peak inspiratory flow may be < 2.0 L/s, and a metered dose inhaler and spacer should be considered. Further studies that investigate the relationship between expiratory flow and peak inspiratory flow against an internal resistance are needed.

show abstract

Section: Discussionmentioning

confidence: 75%

Peak inspiratory flows in children with cystic fibrosis

Gauld

Briggs

Robinson

2003

J Paediatrics Child Health

View full text Add to dashboard Cite

show abstract

“…This method requires precise dose delivery to the lung during normal patient use of their inhalation delivery system. Dry powder inhalers (DPIs) are one of several inhalation aerosol delivery systems that have been investigated for this role (3)(4)(5)(6). The majority of commercially available DPIs consist of micronized drug powder mixed with an inert carrier, usually lactose or pure drug processed to improve its bulk flow properties.…”

Section: Introductionmentioning

confidence: 99%

Effect of rise in simulated inspiratory flow rate and carrier particle size on powder emptying from dry powder inhalers

Chavan

Dalby

2000

AAPS PharmSci

View full text Add to dashboard Cite

The purpose of this study was to evaluate the effect of carrier particle size and simulated inspiratory flow increase rate on emptying from dry powder inhalers (DPIs). Several flow rate ramps were created using a computer-generated voltage signal linked to an electronic proportioning valve with a fast response time. Different linear ramps were programmed to reach 30, 60, 90, and 120 L/minute over 1, 2, or 3 seconds. At the lower flow rates, 100-ms and 500-ms ramps were also investigated. Three DPIs, Spinhaler, Rotahaler, and Turbuhaler, were used to test the effect of flow rate ramp on powder emptying. To test the effect of carrier particle size, anhydrous lactose was sieved into 3 particle sizes, and 20 mg of each was introduced into #2 and #3 hard gelatin capsules for Spinhaler and Rotahaler, respectively. Emptying tests were also carried out using the on/off solenoid valve described in the United States Pharmacopeia (USP) (resulting in no ramp generation). Powder emptying increased from 9% to 46% for Rotahaler and 69% to 86% for Spinhaler from the shallowest (3 seconds to reach peak flow) to the 100-ms ramp for the 53- to 75 microm lactose size range at 30 L/minute. Similar trends were observed for larger particle size fractions at the same flow rate. However, at higher airflow rates (60, 90, and 120 L/minute), there was no significant increase in percentage of emptying within the ramps for a particular particle size range. Trends observed were similar for placebo-filled Turbuhaler and commercially available Rotacaps used with Rotahaler, with the steepest ramp demonstrating more complete emptying. Percentage of powder emptying determined by the USP solenoid valve overestimated the emitted dose compared with the ramp method at 30 L/minute for all 3 devices. Results indicate that there is a significant difference in powder emptying at 30 L/minute from the shallowest to the steepest ramp within a particular size range. Within a particular particle size range, the USP method produced more complete emptying than even the steepest ramp, especially at the lower flow rates. Thus, when the USP device is used to estimate DPI emptying at lower flow rates, the results are likely to overestimate DPI performance significantly.

show abstract

“…Children aged 7-16 years with mild to moderate stable asthma have been shown to generate inspiratory rates of 60 l/min or more when using this device. 38 The Clickhaler delivers salbutamol (a short-acting β 2 -agonist bronchodilator) or beclometasone dipropionate (an anti-inflammatory corticosteroid).…”

Section: Clickhalermentioning

confidence: 99%