In vitro fine particle dose of drug formulation used in asthma & COPD

Abstract

Valved holding Chambers (VHCs) are used with pressurized metered dose inhalers (pMDIs) to counter issues patients have in coordinating pMDI actuation and inhalation. The fine particle dose (FPD <4.7μg) of aerosol from the pMDI & VHC should be similar to the FPD from the pMDI.

We reviewed in vitro test results of FPD from the VHC (OptiChamber Diamond; OCD) when used with 7 drugs commonly used for the treatment of asthma and COPD. The 7 pMDI drugs (Table 1) included 2 inhaled corticosteroids (Flovent and QVAR), 1 anticholinergic (Atrovent) and 4 bronchodilator formulations of salbutamol sulphate (SALB; Ventolin Evohaler sold in the UK, Ventolin HFA, Proventil and ProAir HFA sold in the USA). Two pMDI’s were used for each drug except Flovent, QVAR and Atrovent (1 pMDI), all were tested in duplicate. Six new, unwashed VHCs were used for all drugs except QVAR (6 washed VHCs). The FPD of aerosol emitted from either pMDI alone or pMDI with OCD VHC was assessed using a next generation impactor operated at 30 L/min, 10 pMDI actuations were used for each run.

FPD from the pMDI with VHC was equivalent or greater than pMDI alone. Although the 4 bronchodilator drug formulations delivered the same drug (SALB) the FPD differed by up to a factor of 2.