Apparatus and a concomitant method for electrostatically depositing select doses of medicament powder at select locations on a substrate. Specifically, the apparatus contains a charged particle emitter for generating charged particles that charge a predefined region of a substrate and a charge accumulation control circuit for computing the amount of charge accumulated upon the substrate and deactivating the emitter when a selected quantity of charge has accumulated. Additionally, a triboelectric charging apparatus charges the medicament powder and forms a charged medicament cloud proximate the charged region of the substrate. The medicament particles within the medicament cloud electrostatically adhere to the charged region. The quantity of charge accumulated on the substrate at the predefined region and the charge-to-mass ratio of the medicament powder in the cloud control the amount (dose) of medicament deposited and retained by the substrate. Consequently, this apparatus accurately controls both medicament dosage and deposition location. Furthermore, since the substrate can be of any dielectric material that retains an electrostatic charge, the apparatus can be used to deposit medicament on substrates that are presently used in oral medicament consumption, e.g., substrates that are used to fabricate suppositories, inhalants, tablets, capsules and the like.
A method and a device involving an electric iris diaphragm/shutter are disclosed for controlling particle transfer of electrically charged medication powder particles from a source to a defined target area, of a substrate. Spatial distribution of particles onto the target area is achieved by an electro-dynamic field technique (320) applied to the distribution and deposition of particles in a dose forming process. An electric iris diaphragm/shutter (130) is located between a particle generator (110) and the substrate (140) such that all particles must pass the iris diaphragm for being transferred to the substrate. By adjusting amplitude and frequency of a superimposed AC potential (136) charged particles will oscillate in the created AC field such that only small light particles will emerge from the iris diaphragm/shutter for further transfer in the dose forming process.
An electro-dose constitutes a metered medical powder and is formed from an electro-powder constituting an active powder substance or a dry powder medical formulation being transferred onto a device member forming a dose carrier. The electro-dose prepared from an electro-powder presents a fine particle fraction (FPF) having of the order 50% or more of its content with a particle size between 0.5-5 .mu.m. The electro-powder of such a metered electro-dose further provides electrostatic properties regarding absolute specific charge per mass after charging of the order 0.1 to 25 .mu.C/g and presents a charge decay rate constant Q.sub.50 of more than 0.1 sec with a tap density of less than 0.8 g/ml and a water activity a.sub.w of less than 0.5. The electro-dose porosity is adjusted to obtain an optimized porosity value in percent of 75 to 99.9 calculated as 100-100.times.(Density.sub.electro-dose /Density.sub.electro-powder).
Provided is, among other things, a conductive inlay film comprising: a layer of dielectric film having a pattern of holes suitable to define selected regions to which particles will be deposited by electrostatic deposition; and a conductive element comprising polymer, which element comprises (a) a conductive film laminated against the dielectric film or (b) a conductive film embedded within the holes, the portion of the conductive element appearing within the holes comprising conductive inlays, wherein the conductive element is adapted to contact one or more electrode pads and provide electrical potentials at the selected regions, and wherein the dielectric film electrically isolates the selected regions.
Provided is a method of moving a charged particle from a first position at which it is retained by a first electrode to a second position at which it is retained by a second electrode, the method comprising: applying a potential to the second electrode to attract the particle; and applying a potential to a guide electrode offset from the particle at the first position, wherein the applied potential is effective to reduce the attraction of the particle to the first position sufficiently to allow the potential applied at the second electrode to be effective to move the particle from the first position to the second position.
A dry powder inhaler has a dispersion chamber containing beads. A dose of dry powder is released into the chamber, or into an inlet tangentially joining into the chamber. As the patient inhales on a nosepiece or mouthpiece, air moves circularly through the dispersion chamber to drive the beads. The beads roll, bounce, and collide repeatedly with the drug particles on the chamber surfaces or on the beads. The smaller active drug particles are separated from the larger carrier particles and from each other, and a powder aerosol is created and inhaled by the patient. The beads are preferably lightweight, so that they can be rapidly accelerated and moved, even with nominal inspiration. The flow resistance of the inhaler is also reduced via the beads, allowing greater air flow and powder dispersion, without any increased effort by the patient.
