Distribution of technetium-99m-labelled QVAR™ delivered using an Autohaler™ device in children

Abstract

QVAR™, an extrafine hydrofluoroalkane/beclomethasone dipropionate formulation, has been shown to double lung deposition in adults. The aim of the present study was to assess the total body deposition and distribution of technetium-99m-labelled (99mTc QVAR™ in children after inhalation via an Autohaler™. Sixteen male asthmatic children (5-14 yrs) inhaled labelled drug (<4 MBq 99mTc; 100 μg beclomethasone dipropionate) via an Autohaler within 30 min after salbutamol (200 μg) administration. Simultaneous anterior and posterior planar scintigraphic scans (120 s acquisition time) were collected after inhalation of labelled drug. Mean±SD lung deposition of labelled drug (attenuation-corrected; percentage of ex-actuator dose) was 36.9±9.2, 46.5±11.6 and 54.110.7%) in children aged 5-7, 8-10 and 11-14 yrs, respectively. Combined oropharyngeal and gastrointestinal deposition was 59.7±8.2, 48.9±12.3 and 40.3±11.8%. Lung deposition positively correlated with the forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). Gastrointestinal dose negatively correlated with the FEV1, FVC, height and age. In older children (11-14 yrs), lung deposition was almost identical to that reported in adults using QVAR™. In children aged 5-10 yrs, lung deposition using QVAR™ was greater than the levels measured using other commercial aerosol delivery systems. Oropharygeal and gastrointestinal deposition was inversely related to age.