Apparatus and method for determination of the fine particle dose of a powder inhalation formulation
Inventors
Assignees
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Publication Number
US-10724928-B2
Publication Date
2020-07-28
Expiration Date
Abstract
In an apparatus for collecting aerosolised respirable particles of an inhalable medicinal formulation, aerosolised formulation is drawn pneumatically through a dose collection section comprising an inlet orifice (201) and an air-permeable filter (206), the filter being positioned opposed to said orifice, and extending across the pathway (4) for filtering the pneumatic flow so as to retain particulate material therein on the filter, and the orifice (201) being so dimensioned and configured that it has an unimpeded area that is no less than 75% of the area of the filter (201) on which the dose will be collected. In a method using the apparatus, particles (209, 210) collected on the filter may optionally be subjected to a dissolution test. A good correlation is obtainable between in vitro and in vivo doses with improved independence of loading.
Core Innovation
The invention relates to an apparatus and associated methods for collecting aerosolised respirable particles of an inhalable medicinal formulation. An inlet receives an aerosolised dose and a suction source generates a pneumatic flow through a channel extending to a dose collection section. The dose collection section includes an inlet orifice and a filter unit with an air-permeable filter positioned opposed to the inlet orifice so that the filter retains particulate material on the filter.
The inlet orifice is dimensioned and configured to have an unimpeded area no less than 75% of the area of the filter on which the dose is collected. The filter support is configured to support a central region of the air-permeable filter using one or more support members extending across the pathway on the surface of the air-permeable filter opposed to the inlet orifice, and the filter support defines from two to six apertures and obstructs no more than 80% of the surface area of said opposed surface.
In the method aspects, the invention includes determining dissolution characteristics of an inhalable medicinal formulation by generating an aerosolised dose containing respirable and non-respirable particles. Non-respirable particles are removed by inertial separation and a pneumatic flow carrying respirable particles is delivered along a substantially unimpeded pathway to a filter unit, where filtration retains the particles on the filter and the filter carrying the collected particles is subjected to a dissolution test.
Claims Coverage
The provided portion contains three independent claims that share a common apparatus or method core centered on suction-driven pneumatic delivery of a respirable aerosol fraction to an air-permeable filter using an unimpeded inlet and a defined, minimally obstructive filter support.
Unimpeded inlet orifice opposed air-permeable filter with minimally obstructive filter support
An apparatus for collecting aerosolised respirable particles, comprising an inlet receiving an aerosolised dose, a suction source generating pneumatic flow through a channel, and a dose collection section with an inlet orifice and a filter unit including an air-permeable filter opposed to the inlet orifice and extending across the pathway to retain particulate material, wherein the inlet orifice has an unimpeded area no less than 75% of the area of the filter on which the dose will be collected, with suction communicating with the pathway downstream of the filter unit and a filter support having one or more support members extending across the pathway on the surface of the air-permeable filter opposed to the inlet orifice for supporting a central region of the air-permeable filter, the filter support defining from two to six apertures and obstructing no more than 80% of the surface area of said opposed surface.
Inertial separation of non-respirable particles and unimpeded pneumatic delivery to a defined filter unit
A method for collecting an aerosolised respirable fraction, comprising generating an aerosolised dose containing respirable and non-respirable particles, removing particles of a non-respirable size by inertial separation, delivering a pneumatic flow carrying respirable particles along an unimpeded pathway to a filter unit comprising a filter and a filter support, and effecting filtration to retain particles on the filter, wherein the filter support comprises one or more support members extending across the pathway on the surface of the filter for supporting a central region of the filter, defining from two to six apertures and obstructing no more than 80% of the surface area of said filter.
Aerosolisation, inertial separation, filtration retention on a defined filter support, and dissolution testing
A method for determining the dissolution characteristics of an inhalable medicinal formulation, comprising generating an aerosolised dose containing respirable and non-respirable particles, removing non-respirable particles by inertial separation, delivering a pneumatic flow carrying the respirable particles along a substantially unimpeded pathway to a filter unit comprising a filter and a filter support, effecting filtration such that particles are retained on the filter, and subjecting the filter carrying said collected particles to a dissolution test, wherein the filter support comprises one or more support members extending across the pathway on the surface of the filter for supporting a central region of the filter, defining from two to six apertures and obstructing no more than 80% of the surface area of said filter.
Across the independent claims, the inventive concept is the combined use of an unimpeded or substantially unimpeded pneumatic pathway to an air-permeable filter, inertial separation to remove non-respirable fractions in the method claims, and a filter support geometry that supports a central region while defining two to six apertures and obstructing no more than 80% of the filter surface area opposed to the inlet orifice.
Stated Advantages
Improved reproducibility of dissolution characteristics versus dependence on number of actuations.
Reduced dependence on number of actuations.
Improved in vitro–in vivo correlation (IVIVC).
Validated correlation of collected dose versus standard NGI impactor stage mass (ISM).
More even deposition on the filter compared with conventional multi-nozzle impactors.
Documented Applications
Determining dissolution characteristics of an inhalable medicinal formulation by collecting aerosolised respirable particles on a filter and performing a dissolution test on the collected particles.
Collecting aerosolised respirable fractions of inhalable medicinal formulations including respirable and non-respirable particle size fractions using inertial separation and filter retention.
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