Applicator for applying a fluid to a surface

1. An applicator for applying a fluid to a surface, the applicator comprising:

1) a support comprising an upper outer surface and a lower holding surface;

2) a flexible membrane comprising:

a central opening,

an inner wall comprising a lower end and an upper end,

an outer wall at least partially surrounding the upper outer surface of the support, the outer wall comprising a lower end and an upper end, and

an upper folded wall connecting the upper ends of the inner wall and outer wall; and

3) a membrane holder for fixedly securing the lower end of the inner wall of the flexible membrane to the upper outer surface of the support;

wherein the upper surface of the membrane holder and the inner wall of the flexible membrane define a reservoir for holding a fluid, and

wherein the lower end of the outer wall of the flexible membrane is free to move axially relative to the upper outer surface of the support when pressure is applied to the upper folded wall of the flexible membrane.

2. An applicator according to claim 1 , wherein the support is open at a lower end thereof adapted to removably mount on a dispenser bottle containing a fluid.

3. An applicator according to claim 1 , wherein the support is adapted to engage a cap to cover the flexible membrane.

4. An applicator according to claim 1 , wherein the membrane holder covers and closes the central opening of the flexible membrane.

5. An applicator according to claim 1 , wherein the upper folder wall of the flexible membrane deforms relatively uniformly around its perimeter along an axis that is transverse to central opening when pressure is applied to the upper folder wall.

6. An applicator according to claim 5 , wherein a vacuum seal is formed when pressure is applied to the upper folder wall against a solid or semi-solid surface.

7. An applicator according to claim 1 , further comprising a skirt secured to the lower end of the outer wall of the flexible membrane, the skirt having dimensions larger than outer dimensions of the upper outer surface of the support for freely moving axially relative to the upper outer surface of the support when pressure is applied to the upper folded wall of the flexible membrane.

8. An applicator according to claim 1 , wherein the membrane holder is fixedly secured to the lower end of the inner wall of the flexible membrane by a securement member such that the flexible membrane is secured to the upper outer surface of the support in a fluid sealing manner.

9. An applicator according to claim 2 , wherein the membrane holder is fixedly secured to the lower end of the inner wall of the flexible membrane by an adhesive.

10. A kit comprising an applicator according to claim 1 , a dispenser bottle containing a fluid, and a cap adapted to engage the support and cover the flexible membrane of the applicator.

11. A kit comprising an applicator according to claim 2 , a dispenser bottle containing a fluid, and a cap adapted to engage the support and cover the flexible membrane of the applicator.

12. A kit according to claim 10 , wherein the dispenser bottle contains a topical or transdermal testosterone composition.

13. A kit according to claim 11 , wherein the dispenser bottle contains a topical or transdermal testosterone composition.

14. A method of applying a topical or transdermal testosterone composition to the skin of a human in need thereof, the method comprising providing an applicator according to claim 1 , placing the topical or transdermal testosterone composition in the reservoir of the applicator, and applying the topical or transdermal testosterone composition from the reservoir to the skin.

15. A method according to claim 14 , wherein the human is a male.

16. A method according to claim 15 , wherein the male is suffering from primary hypogonadism or hypogonadotropic hypogonadism.

17. A method according to claim 16 , wherein the topical or transdermal testosterone composition is applied to one or more axilla of the male.

18. A method according to claim 16 , wherein a serum testosterone concentration of approximately 300 ng/dL to about 1050 ng/dL is achieved following one or more applications of the topical or transdermal testosterone composition.

19. An applicator for applying a fluid to a surface, the applicator comprising:

1) a support comprising an upper outer surface and a lower holding surface;

2) a flexible membrane comprising:

a central opening,

an inner wall comprising a lower end and an upper end,

an outer wall at least partially surrounding the upper outer surface of the support, the outer wall comprising a lower end and an upper end, and

an upper folded wall connecting the upper ends of the inner wall and outer wall;

3) a membrane holder for fixedly securing the lower end of the inner wall of the flexible membrane to the upper outer surface of the support; and

4) a skirt secured to the lower end of the outer wall of the flexible membrane, the skirt having dimensions larger than outer dimensions of the upper outer surface of the support,

wherein the upper surface of the membrane holder and the inner wall of the flexible membrane define a reservoir for holding a fluid,

wherein the lower end of the outer wall of the flexible membrane and the skirt are free to move axially relative to the upper outer surface of the support when pressure is applied to the upper folded wall of the flexible membrane, and for freely moving axially relative to the upper outer surface of the support when pressure is applied to the upper folded wall of the flexible membrane.