Diffusion Cell Clamping and Assembly Tools

Abstract

A diffusion/permeation cell, commonly referred to as a Franz cell, is provided for topical or transdermal drug delivery research and development in the pharmaceutical industry. The cell comprises a receptor container, a donor chamber, a quick clamping apparatus, and/or an assembly tool. Systems and methods provide a cost-effective diffusion cell, especially for use with an automatic diffusion release testing system.

Claims

1. A diffusion cell, comprising: a receptor container, a donor chamber, and a quick clamping apparatus, comprising: a clamping nut, a donor cap, and a pressing screw, wherein the diffusion cell is directed to at least one of topical and transdermal drug diffusion testing.

2. The diffusion cell of claim 1, wherein the clamping nut has a U-shape bottom plate and the threads on its upper body.

3. The clamping nut of claim 1, wherein the preferred material for the clamping nut is plastics and made by 3D printing or injection model fabrication.

4. The clamping nut of claim 1, wherein the donor cap is made from inert material comprising at least one of glass and teflon.

5. The diffusion cell of claim 1, wherein the pressing screw has an opening at its center and the threads on its body, wherein a preferred material is plastics and made by 3D printing or injection model fabrication.

6. A diffusion cell assembly tool, comprising: a body; its top surface; a recess; raised pallets; and baffle plates.

7. The diffusion cell assembly tool of claim 6, wherein the top surface has a contour profile of the U-shape bottom plate of the clamping nut.

8. The diffusion cell assembly tool of claim 6, wherein the recess has a contour profile of the receptor container of the diffusion cell.

9. The diffusion cell assembly tool of claim 6, wherein a height of the raised pallets is equal to a height of the U-shape bottom plate of the clamping nut.

10. The diffusion cell assembly tool of claim 6, wherein the baffle plates are higher than the thickness of the annular flange of the receptor container.

11. The diffusion cell assembly tool of claim 6, wherein the body of the tool is made from 3D printing or plastic injection model.

12. A method of assembling a diffusion cell, comprising: placing a donor plate with a center opening atop a membrane to form a donor chamber; filling the donor chamber with donor material; placing the donor plate, the membrane, and the donor material on a top surface of a receptor fluid container; inserting the donor plate, the membrane, the donor material, and the top surface through a side opening of a clamping nut; placing a donor cap on a top of the donor plate through a threaded opening of the clamping nut; and screwing a pressing screw down to the clamping nut.

13. The method of claim 12, wherein the screwing action results in pressure on the donor cap.

14. The method of claim 12, wherein the donor cap, the donor plate, and the membrane are fastened to the top flat surface of the receptor container through a quick clamping apparatus.

15. The method of claim 12, wherein the donor material is in contact with an upper surface of the membrane.

16. The method of claim 12, wherein a lower surface of the membrane is in continuous contact with the receptor liquid in the receptor fluid chamber.

17. The method of claim 16, wherein the continuous contact promotes testing of penetration by active ingredients of the donor material through the membrane into the receptor fluid chamber.

18. The method of claim 17, wherein the testing is conducted through sampling the receptor liquid.

19. The method of claim 12, further comprising the donor cap is made from inert material comprising at least one of glass and teflon.

20. The method of claim 12, further comprising the pressing screw has an opening at its center and the threads on its body, wherein the screw is formed via plastic injection molding methods.

Description

BRIEF DESCRIPTION OF THE FIGS.

[0019] 15. FIG. 1 is an exploded perspective view of an embodiment of a diffusion cell together with a receptor container, a donor chamber, and a quick clamping apparatus;

[0020] 16. FIG. 2 is a perspective view of the clamping part 40 depicted in FIG. 1;

[0021] 17. FIG. 3 is a perspective view of the pressing part 30 depicted in FIG. 1;

[0022] 18. FIG. 4 is a perspective view of an assembled diffusion cell with the clamping system provided herein with a membrane and a drug solution holder;

[0023] 19. FIG. 5 is an A-A sectional view of the assembled diffusion cell with a membrane and a drug solution holder depicted in FIG. 4;

[0024] 20. FIG. 6 is a perspective view of an embodiment of an assembly tool for the diffusion cell shown in FIGS. 1-5;

[0025] 21. FIG. 7 illustrates an assembly procedure of the diffusion cell with the assembly tool in FIG. 6.

[0026] 22. FIG. 8 illustrates the assembled diffusion cell releasing from the top of the assembly tool.

DETAILED DESCRIPTION

[0027] 23. Referring the figures, a diffusion cell 10 is provided. The diffusion cell 10 includes a thin walled receptor container 50, which is normally constructed of glass with a receptor fluid chamber 52, an annular flange 51, and a fluid sampling and refilling tube 53. The receptor fluid chamber 52 has a closed bottom and an open top.

[0028] 24. The annular flange 51 at the upper portion of the receptor container 50 is expanded to be of a greater diameter than the lower portion of the chamber 52. A flat surface 54 is at the top of the annular flange 51. The receptor fluid chamber 52 is filled with receptor fluid that may be water, saline or other liquids.

[0029] 25. The receptor fluid may be sampled and refilled by means of the sampling and refilling tube 53. Normally, a syringe pump with a long needle is used to perform the sampling and refilling the receptor fluid. The long needle with smaller diameter than the tube size of the sampling and refilling tube 53 is inserted into the receptor fluid chamber 52. The opening of the tube 53 is higher than the flat surface 54 of the receptor fluid chamber 52.

[0030] 26. A membrane 61 is placed on the flat surface 54. The function of the membrane 61 is to essentially simulate human skin or animal skin and form the closed receptor fluid chamber 52 that is the body under the skin. The membrane 61 could be a cadaver skin or could be a synthetic material that essentially simulates human skin. On the membrane 61 is located a donor plate 62.

[0031] 27. The donor plate 62 is in the shape of a washer of a certain thickness with a center opening that is as same as the opening of the receptor fluid chamber 52 in diameter. Typically, the donor plate 62 is constructed of silicone rubber, but other materials such as glass, teflon, or plastic can be used. The opening of the donor plate 62 together with the membrane 61 forms a donor chamber 63. A donor material that is in the form of an ointment, a cream, or a semi-solid material such as a gel, is filled the donor chamber 63.

[0032] 28. On the top of the donor plate 62, a donor cap 30 is located. The donor cap 30 comprises an annular flange 31, a central opening 33, and a tubular structure 32. The annular flange 31 is as same as the annular flange 51 on the receptor fluid chamber 52 in outer side diameter. The center opening is also as same as the center opening of the donor plate 62 in diameter. The tubular structure 32 is designed for observation of donor material in the donor chamber and refilling of donor material. The donor cap 30 is made of inert material such glass or teflon.

[0033] 29. It may be desirable and necessary for the donor plate 62 and the membrane 61 to be tightly restrained in position between the annular flange 31 of the donor cap 30 and the annular flange 51 of the receptor fluid container 50. To achieve this, a quick clamping apparatus is used, which is constructed by a clamping nut 40 and a pressing screw 20.

[0034] 30. The clamping nut 40 comprises a body 41, a U-shaped bottom plate 42, a side opening 45 and 47, and threads 43 at its upper body. The U-shaped bottom plate 42 has the lower opening 45 with the dimension equal to the diameter of the lower portion of the receptor fluid container 50, and upper opening 47 with the dimension equal to the diameter of the annular flange 51.

[0035] 31. The annular flange 51 of the receptor fluid container 50 can be inserted into the clamping nut 40 through the side opening 45 and 47. The bottom surface of the annular flange 51 attached to the top surface 46 of the U-shaped bottom plate 42.

[0036] 32. The pressing screw 20 comprises an opening 21 and threads 22. The opening 21 allows the tubular structure 32 of the donor cap 30 to be put through. The threads 22 is same as the threads 43 on the clamping nut 40.

[0037] 33. For assembly of the diffusion cell, as the first embodiment of this invention, the following steps are involved: [0038] 1) The donor plate 62 is placed on the top of the membrane 61. [0039] 2) The donor material in a form of an ointment, a cream, or a semi-solid, is filled the donor chamber 63. [0040] 3) The donor plate 62, the membrane 61, and the donor material filled in the donor chamber are placed on the top surface 54 of the receptor fluid container 50. Together they are inserted into the clamping nut 40 through its side opening 45 and 47. The bottom surface of the annular flange 51 is attached to the top surface 46 of the U-shaped bottom plate 42. [0041] 4) The donor cap 30 is placed on the top of the donor plate 62 through the threads 43 opening of the clamping nut 40. [0042] 5) The pressing screw 20 is screwed down to the clamping nut 40, which presses on the donor cap 30, so that the diffusion cell is assembled.

[0043] 34. The donor cap 30, the donor plate 62, and the membrane 61 are fastened to the top flat surface 54 of the receptor container 50 through the quick clamping apparatus. The donor material is in contact with the upper surface of the membrane 61. The lower surface of the membrane 61 is in continuous contact with the receptor liquid in the receptor fluid chamber 52. It can thus be tested how the active ingredients of the donor material penetrates the membrane 61 into the receptor fluid chamber 52, through sampling the receptor liquid.

[0044] 35. The disassembly of the diffusion cell may be accomplished as follows.

[0045] The pressing screw 20 is unscrewed from the clamping nut 40. The donor cap 30, the donor plate 62, and the membrane 61 are released from the top flat surface 54 of the receptor container 50. The receptor container 50 can be then slid out from the opening 45 and 47 of the clamping nut 40.

[0046] 36. The advantages of this embodiment of the diffusion cell with the quick clamping apparatus are: [0047] 1) the pressing screw 20, the donor cap 30, the donor plate 62, the receptor container 50 and the clamping nut 40 are concentric. When they are assembled together, the donor chamber 63 is aligned with the orifice of the receptor fluid chamber 52; [0048] 2) mechanism can be designed on the body of the clamping nut 40 or the donor cap 30 for holding the diffusion cell in place for automatic operation; [0049] 3) the quick clamping apparatus is compact such that after the assembly with the diffusion cell, any effects from shanking, moving, or tilting do not bear on the test results.

[0050] 37. For further improving the operation of the assembly of the diffusion cell 10, FIG. 6 to FIG. 8 show a further embodiment of this invention, an assembly tool 100. The assembly tool 100 consists of a body 101 with top surface 102 and recess 103, raised pallets 104, 105 and 106, and baffle plates 107 and 108. The recess 103 takes the contour profile of the receptor container 50, which accommodates the receptor container 50.

[0051] 38. The top surface 102 takes the U-shape contour profile of the clamping nut 40. The raised pallets 104, 105 and 106 support the annular flange 51 of the receptor container 50. On the bottom plate 42 of the clamping nut 40 there is a recess 48 to fit the raised pallet 104. The baffle plates 107 and 108 are used to prevent the shifting or incorrect positioning of the donor plate 62 and the membrane 61 during the assembly.

[0052] 39. To assemble the diffusion cell on the assembly tool, as the second embodiment of this invention, the following steps are involved: [0053] 1) The receptor container 50 is placed into the recess 103, its annular flange 51 is seated on the top of the raised pallets 104, 105 and 106. [0054] 2) The refilled the donor chamber 63 of the donor plate 62 together with the membrane 61 is put on the top surface 54 of the receptor fluid container 50 with the guidance of the baffle plates 107 and 108. [0055] 3) The clamping nut 40 is inserted onto the assembly tool with the receptor fluid container 50, through the U-Shape bottom plate 42 touching the top surface 102, and the top surface 46 of the U-shaped bottom plate 42 attaching the bottom surface of the annular flange 51. [0056] 4) The donor cap 30 is pressed down on the top of the donor plate 62 through the threads 43 opening of the clamping nut 40. [0057] 5) The pressing screw 20 is screwed down to the clamping nut 40, which presses on the donor cap 30. [0058] 6) The diffusion cell is and can be released from the top of the assembly tool 100, as shown in FIG. 8.

[0059] 40. The advantages of this embodiment of the diffusion cell assembly tool are: the assembly tool 100 helps the receptor container 50 in place and the diffusion cell 10 can be assembled together in a prompt fashion. The possible errors caused by incorrect positioning and shifting can be avoided.

[0060] 41. Although the present disclosure has been provided with reference to the particular embodiments described herein, it is to be understood that these embodiments are merely illustrative of certain principles and applications of the present invention. Numerous modifications may be made to the illustrative embodiments and other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the claims.