Method of depositing particles with an electrostatic chuck

• US 6,440,486 B2
• Filed: 12/19/2000
• Issued: 08/27/2002
• Est. Priority Date: 04/09/1996
• Status: Expired due to Fees

• Current Assignee: Delsys Pharmaceutical Corporation (Perrigo Company PLC)
• Original Assignee: Delsys Pharmaceutical Corporation (Perrigo Company PLC)
• Inventors: Pletcher, Timothy Allen, Sun, Hoi Cheong Steve
• Primary Examiner(s): Parker, Fred J.
• Application Number:
  US09/740,123
• Publication Number:
  US 20010018098A1
• Time in Patent Office: 616 Days
• Field of Search: 427/2.14, 427/466, 427/469, 427/475, 427/485
• US Class Current: 427/2.14
• CPC Class Codes: A61K 9/2086 Layered tablets, e.g. bilayer tablets; Tablets of the type inert core-active coat active cores with a complete drug-free outer coat A61K9/28
• CPC Class Codes: A61K 9/2893 Tablet coating processes mechanical aspects A61J3/06
• CPC Class Codes: B01J 2219/00468 by manipulation of individual beads
• CPC Class Codes: B05B 5/08 Plant for applying liquids or other fluent materials to objects
• CPC Class Codes: B05B 5/082 characterised by means for supporting, holding or conveying the objects
• CPC Class Codes: B05B 5/087 Arrangements of electrodes, e.g. of charging, shielding, collecting electrodes B05B5/12, B05B5/14 take precedence; arrangements of electrodes on the discharge apparatus B05B5/0533
• CPC Class Codes: H02N 13/00 Clutches or holding devices using electrostatic attraction, e.g. using Johnson-Rahbek effect
• CPC Class Codes: Y10T 428/2991 Coated

Abstract

The present invention is directed to electrostatic chucks, methods for their use, the electrostatic deposition of objects, such as particles in a dry powder, onto recipient substrates, and the recipient substrates themselves that have been subjected to electrostatic deposition. In one aspect, the present invention provides an electrostatic chuck for electrostatically attracting an object or objects wherein the object is used in chemical or pharmaceutical assaying or manufacturing. The objects can be pharmaceutical substrates, for example, such as a pharmaceutical tablet. Additional embodiments of the invention provide chucks and their use to electrostatically attract particles, such as a pharmaceutically active ingredient, to a substrate, such as a tablet. In one aspect, the electrostatic chuck comprises a floating electrode, and is used to selectively attract particles to a substrate above the floating electrode, thereby providing for charge imaging for the deposition of particles in a selected image. Additionally, the invention provides comprising a sensing electrode, optionally for use with an electrostatic chuck, for sensing the number of particles attracted to the objects on the chuck or other substrate, thereby providing for deposition of an accurate amount of particles. Furthermore, the present invention provides objects having selected areas in which particles are applied to the object via electrostatic means.

Claims

1. A method of manufacturing a pharmaceutical composition comprising:

(a) adhering a pharmaceutical substrate to an electrostatic chuck; and

(b) applying particles to the pharmaceutical substrate which is adhered to the electrostatic chuck, and electrostatically adhering the particles to the substrate.

2. The method according to claim 1, wherein the electrostatic chuck comprises a floating electrode and the particles are substantially adhered on an area of the pharmaceutical substrate corresponding to an area overlaying the floating electrode.

3. The method according to claim 2, further comprising:

(c) selecting a bias potential for application to the electrostatic chuck to establish the amount of the applied particles that will adhere to the pharmaceutical substrate; and

(d) applying the bias potential to the electrostatic chuck.

4. The method according to claim 1, further comprising:

(e) measuring the amount of the particles deposited on the pharmaceutical substrate by measuring ion currents induced by the particles deposited on a sensing electrode during the application of the particles to the pharmaceutical substrate.

5. The method according to claim 4, further comprising:

(f) when the measured amount of deposited particles reaches a target amount, terminating the application of the particles.

6. The method according to claim 1, wherein the pharmaceutical substrate is selected from the group consisting of an edible polymeric substrate and inhaler substrate.

7. The method according to claim 1, wherein the pharmaceutical substrate is selected from the group consisting of a tablet, film, capsule, caplet, suppository, dressing, bandage and a patch.

8. The method of claim 1, comprising

(g) triboelectrically charging the particles to promote their electrostatic adherence to the pharmaceutical substrate.

9. A method of manufacturing a coated substrate comprising:

(a) adhering a substrate to an electrostatic chuck that comprises a floating electrode; and

(b) applying particles to the substrate applied to the electrostatic chuck and electrostatically adhering particles to coat the substrate, wherein the particles are substantially adhered on an area of the substrate corresponding to an area overlaying the floating electrode.

10. The method according to claim 9, further comprising:

(e) measuring the amount of the particles deposited on the substrate by measuring ion currents induced by the particles deposited on a sensing electrode during the application of particles to the substrate.

11. The method according to claim 10, further comprising:

(f) when the measured amount of deposited particles reaches a target amount, terminating the application of particles.

12. The method according to claim 9, wherein the substrate is selected from the group consisting of an edible polymeric substrate and inhaler substrate.

13. The method according to claim 9, wherein the substrate is selected from the group consisting of a tablet, film, capsule, caplet, suppository, dressing, bandage and a patch.

14. A method of manufacturing a coated substrate comprising:

(a) adhering a substrate to an electrostatic chuck,

(b) applying particles to the substrate applied to the electrostatic chuck and electrostatically adhering the particles to the substrate;

(c) selecting a bias potential for application to the electrostatic chuck to establish the amount of the applied particles that will adhere to the substrate; and

(d) applying the bias potential to the electrostatic chuck.