Apparatus and method for manufacturing microneedles

#Apparatus and methods are disclosed for manufacturing a microneedle array consisting of spaced-apart microneedles integral with and extending above a base sheet. A channel is formed extending from the tip of the microneedle through the base allowing fluids to pass completely through the microneedles in the array.

#Prior art patents document the uses to which such microneedles are intended to be put and demonstrate known efforts to manufacture microneedles. In particular, U.S. Pat. Nos. 6,471,903, 6,451,240, 6,379,324, 6,312,612 and 6,256,533, all assigned to the Procter & Gamble Company describe in great detail the characteristics and uses of such microneedle arrays. To date, the manufacturing processes detailed in these references have proven less than satisfactory on a commercial scale.

#Preferably, the microneedle array is made from a polymer with flow characteristics that will take on the shape of the mold form and allow channels to be formed through the needles. Polymers such as urethanes, polysulfone, nylon, polycarbonates, acrylic and formulated radiation curable products may be used. The polymer may be applied in liquid form at a thickness of about 125 to 250 microns (0.005 to 0.010 inches thick) and may be heat cured, or room temperature cured, ultraviolet cured or cured by other radiation wavelengths. An alternative method is to apply the polymer as a film sheet then heat the polymer to a liquid state and cool back to a solid state once it has been formed with the gas channels.

#These and further objects of the present invention will become apparent upon consideration of the drawings in which:

#FIG. 1 is a perspective view of an apparatus for the manufacture of microneedle arrays showing the upper and lower manifold attached one to the other;

#FIG. 2 is a perspective view of the lower manifold separated from the upper manifold;

#Referring now to FIG. 1, the numeral 10 indicates generally a mold assembly having a lower manifold 12 and an upper manifold 14. Attached fluid tightly to lower manifold 12 is a gas inlet coupling 16 and in like fashion, a gas outlet coupling 18 is attached fluid tightly to upper manifold 14.

#Referring now to FIG. 2, lower manifold 12 is seen separated from upper manifold 14. Lower manifold 12 has a top surface 20 through which a pair of gas ports 22, 24 are drilled communicating with an inner, hollow inlet bore 26 shown schematically in FIG. 8. Bore 26 extends to communicate with a gas inlet 28 to which coupling 16 is attached.

#Referring now to FIG. 3, a gasket material 30 is placed on top surface 20 of lower manifold 12. In the embodiment shown in FIG. 3, pad 30 is formed from silicone rubber and has pad openings 32, 34 sized and positioned to align with ports 22 and 24.