We have
performed a first clinical investigation of the device which was
a gamma scintigraphy lung deposition study, using inhalation through
the mouth. This study was conducted at Pharmaceutical Profiles,
in UK, between January and March 2001.
The aim of this study was to assess the in vivo performance of the FlowCaps® dry
powder inhaler using an experimental radiolabelled budesonide engineered particles
formulation delivered with low inspiratory effort (30 L/min). Lung deposition
was the highest when compared to published results.
Methods
Seven healthy, non smoking volunteers (3M 4F) completed a single-leg gamma scintigraphic
study, assessing the lung and oropharyngeal deposition of radiolabelled budesonide
formulation.
A radiolabelling method was developed using the radionuclide 99mTc, which was
subsequently validated by testing with a multistage liquid impinger.
Before dosing, volunteers were trained to perform the inhalation maneuver using
a placebo capsule containing lactose. Volunteers were taught to inhale at 30
L/min followed by a 10 s breath holding pause and exhalation through a filter.
Immediately after inhalation of the radiolabelled formulation, gamma camera images
were taken, enabling both lung and oropharyngeal deposition to be quantified
as percentages of the metered (ex-capsule) dose. Data were corrected for attenuation
of gamma rays (Pitcairn and Newman 1997). The FlowCaps® DPI and capsule were
also imaged after dosing.
The lungs were divided into central, intermediate and peripheral zones, representing
mainly large, medium and small airways, respectively. The peripheral lung zone/central
lung zone deposition ratio (P/C ratio) was calculated as the index of regional
lung deposition.
An actual scintigraphic image of the study for one subject is illustrated
below. |
