Relationship between Amount of Drug Delivered to Lungs and Amount Released from Diskhaler by Inhalation with Tapping

Abstract

It is well known that drug residue remains in a fluticasone propionate Diskhaler (FP-DH) following a single inhalation. Thus, the inspiratory ability of the patient has an influence on the effects of the drug. In a previous study, we reported that the amount of drug remaining in an FP-DH was decreased by tapping the device after the first inhalation. In the present study, we investigated the relationship between the amount of drug delivered to the lungs and amount of drug released from the FP-DH by inhalation along with tapping using an in vitro model. We measured the amounts delivered to the throat, stage 1, and stage 2 of a twin impinger device by HPLC-UV, following inhalation and tapping of 100 m mg of FP-DH at various inspiratory flow rates, which ranged from 11.5 to 73.6 l/min for 2 s. A positive linear correlation between the amount of drug released from the FP-DH and that deposited in stage 2 was observed. Amounts deposited in stage 2 following tapping were estimated to be 6.0 m mg at an inspiratory flow rate of 20 l/min and 10.6 m mg at 60 l/min, while those without tapping were 2.0 m mg and 10.2 m mg, respectively. Notably, at an inspiratory flow rate of 20 l/min, the amount of drug deposited in stage 2 by tapping was increased about 3-fold in comparison to that without tapping. Our results indicate that the amount of drug deposited in stage 2, i.e., the lung in our model, is increased by tapping of the device, which would be particularly helpful for patients with a lower level of inspiratory ability.

Prospective Evaluation of Exacerbations Associated with Suboptimal Peak Inspiratory Flow Among Stable Outpatients with COPD

“… 6 A minimal IF of 30 liters/minute is generally recommended to actuate most DPIs, 6 whereas studies show that higher IFs create smaller drug particle sizes for greater deposition of the medication into the lower respiratory tract. 7 , 8 For low to medium high resistance DPIs, a peak IF (PIF) of at least 60 liters/minute is recommended. 9 Two studies have demonstrated greater improvements in lung function with nebulized therapy compared with DPI in patients with a suboptimal PIF.…”