Patch production

• US 8,883,015 B2
• Filed: 02/05/2009
• Issued: 11/11/2014
• Est. Priority Date: 02/07/2008
• Status: Active Grant

• Current Assignee: Vaxxas Pty Ltd.
• Original Assignee: The University of Queensland
• Inventors: Kendall, Mark Anthony Fernance, Jenkins, Derek William Kenneth
• Primary Examiner(s): FRASER, STEWART A
• Application Number:
  US12/866,717
• Publication Number:
  US 20110223542A1
• Time in Patent Office: 2,105 Days
• Field of Search: 430/320, 430/323, 438/689, 438/694, 216/2, 216/11, 216/27, 216/33
• US Class Current: 216/11
• CPC Class Codes: A61K 9/0021 Intradermal administration, e.g. through microneedle arrays, needleless injectors mechanical aspects A61M
• CPC Class Codes: A61K 9/0097 Micromachined devices; Microelectromechanical systems [MEMS]; Devices obtained by lithographic treatment of silicon; Devices comprising chips intradermal microneedle arrays A61K9/0021; MEMS in general B81B7/02
• CPC Class Codes: A61M 2037/0023 Drug applicators using microneedles
• CPC Class Codes: A61M 2037/0046 Solid microneedles
• CPC Class Codes: A61M 2037/0053 Methods for producing microneedles
• CPC Class Codes: A61M 37/0015 by using microneedles
• CPC Class Codes: B81B 2201/055 Microneedles
• CPC Class Codes: B81C 1/00111 Tips, pillars, i.e. raised structures microneedles A61M37/0015
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32009 Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources plasma generation in general H05H1/24
• CPC Class Codes: H01J 37/3244 Gas supply means

Abstract

A method of producing projections on a patch including providing a mask on a substrate and etching the substrate using an etchant and a passivant to thereby control the etching process and form the projections, wherein the passivant does not include oxygen.

Claims

1. A method of producing projections on a patch, the method including:

a) providing a mask on a substrate; and

,

b) etching the substrate using a mixture of an etchant and a passivant to thereby control the etching process and form the projections, wherein the etching process is controlled by varying a ratio of the etchant to the passivant in the mixture, wherein the ratio is in the range of 0.25 to 0.60, and wherein the passivant does not include oxygen.

2. A method according to claim 1, wherein the mask includes an organic photo-resist.

3. A method according to claim 1, wherein the passivant is a gas including:

a) at least one of;

i) carbon; and

,

ii) silicon; and

,

b) at least one of;

i) chlorine; and

,

ii) fluorine.

4. A method according to claim 1, wherein the passivant is at least one of:

a) a per-fluoride hydrocarbon;

b) a fluorinated olefine;

c) Octafluorocyclobutane;

d) Perfluoroisobutene; and

,

e) C₄F₈.

5. A method according to claim 1, wherein the etchant is a gas or plasma.

6. A method according to claim 1, wherein the etchant is sulfur hexa-fluoride.

7. A method according to claim 1, wherein the method includes, controlling the etching process by varying etching parameters including at least one of:

a) a gas flow for at least one of the etchant and the passivant; and

,

b) a pressure for at least one of the etchant and the passivant.

8. A method according to claim 7, wherein the pressure of at least one of the etchant and the passivant is in the range of 0 to 26.7 Pa.

9. A method according to claim 7, wherein the pressure of at least one of the etchant and the passivant is in the range of 0.67 to 8.0 Pa.

10. A method according to claim 7, wherein the etchant is supplied at a flow rate in the range of 0 to 200 sccm.

11. A method according to claim 1, wherein the passivant is supplied at a flow rate in the range of 0 to 200 sccm.

12. A method according to claim 1, wherein the method includes:

a) applying a mask material to the substrate; and

,

b) selectively exposing the mask material to radiation to thereby form the mask.

13. A method according to claim 12, wherein the mask material is at least one of:

a) an organic photo-resist;

b) a polymer mask; and

,

c) a crosslinked epoxy resin.

14. A method according to claim 12, wherein the mask material is Su-8.

15. A method according to claim 1, wherein the method includes, performing post-etch processing.

16. A method according to claim 15, wherein the method includes, chemically sharpening the projections.

17. A method according to claim 15, wherein the method includes, sharpening the projections by:

a) forming a silicon dioxide layer on the projections; and

,

b) removing the silicon dioxide layer.

18. A method according to claim 17, wherein the method includes forming a silicon dioxide layer on the projections by heating the projections in an oxygen rich environment.

19. A method according to claim 18, wherein the method includes heating the projections to a temperature of greater than 1000°

C.

20. A method according to claim 17, wherein the method includes removing the silicon dioxide using 10% HF.

21. A method according to claim 1, wherein the method includes, applying a coating to the projections.

22. A method according to claim 21, wherein the coating is a metallic coating.

23. A method according to claim 21, wherein the method includes using sputter deposition to deposit:

a) an adhesion layer; and

,

b) a metallic layer on the adhesion layer.

24. A method according to claim 23, wherein the adhesion layer includes chromium.

25. A method according to claim 22, wherein the metallic coating includes gold.

26. A method according to claim 1, wherein the method further includes coating the projections with a material.

27. A method according to claim 26, wherein the material is a therapeutic agent.

28. A method according to claim 1, wherein the patch has a surface area of approximately 0.4 cm².

29. A method according to claim 1, wherein the projections have a density of between 1,000-30,000 projections/cm².

30. A method according to claim 1, wherein the projections have a density of 20,000 projections/cm².

31. A method according to claim 1, wherein the projections have a length of between 10 to 200 μ

m.

32. A method according to claim 1, wherein the projections have a length of 90 μ

m.

33. A method according to claim 1, wherein the projections have a radius of curvature of greater than 1 μ

m.

34. A method according to claim 1, wherein the projections have a radius of curvature greater than 5 μ

m.

35. A method according to claim 1, wherein the projections include a support section and a targeting section.

36. A method according to claim 35, wherein the targeting section has a diameter of less than 1 μ

m.

37. A method according to claim 35, wherein a length for the targeting section is less than 2.0 μ

m.

38. A method according to claim 35, wherein a length for the support section is at least one of:

a) for epidermal delivery <

200 μ

m;

b) for dermal cell delivery <

1000 μ

m;

c) for delivery to basal cells in the epithelium of the mucosa 600-800 μ

m; and

,

d) for lung delivery of the order of 100 μ

m an in this case.