FIELD

The present disclosure generally relates to microneedle arrays used to treat an area of the skin and/or to deliver an active agent to a patient and, more particularly, to equipment and methods of making such microneedle arrays.

BACKGROUND

Microneedle arrays are known in the art. Microneedle arrays have a plurality of very small microneedles that may be hollow or solid and may be coated in a material (e.g. active agent such as drug) that is to be delivered to a patient. Various shapes and arrangements of microneedles in the array are known, as well as various methods for making the microneedle arrays, such as by injection molding. In the case of coated microneedle arrays, various methods for coating a desired material onto the microneedles of a microneedle array are known. To assure proper functioning of the microneedle array in terms of penetration and delivery, it is important that the shape and any coating be as intended.

SUMMARY

It has been found that, despite known methods of manufacturing microneedle arrays and methods of effectively coating material onto a microneedle array, such arrays and coatings are susceptible to variance in the shape of the needles and amount and distribution of material coating on the individual microneedles, as well as variance between individual arrays. The present invention provides equipment and a process of making microneedle arrays wherein the process comprises providing a microneedle array having a plurality of microneedles of a desired shape, illuminating at least a portion of said microneedle array that comprises at least one microneedle, capturing an observed image of said at least one microneedle using an optical device, electronically processing said observed image and determining at least one shape parameter for said at least one microneedle, accepting said microneedle array if said at least one shape parameter is within an acceptable range, thereby providing a microneedle array that comprises a known shape of the plurality of microneedles.

The present invention is particularly useful in the difficult context of microneedle arrays coated with a material (e.g., an active agent) to be delivered from the needles. It is critical that the amount of material be as intended and the present invention provides a reliable, fast, and efficient method of determining the amount of material coating the plurality of microneedles from a single image. It also allows one to determine the distribution of material on the microneedle, which can also be important.

One aspect of the present invention can comprise a light source at a 40° angle to the surface of the coated microneedle array and an optical device above the microneedle array that is located such that a linear line from the microneedle array to the optical device is normal to the surface of the microneedle array. The light source projects light through the microneedles and the corresponding microneedle shadows are observed on the surface of the microneedle array. The image of the microneedle shadows is then processed to determine an amount of material coating the plurality of coated microneedles.

Another aspect of the present invention can comprise equipment for use in an apparatus for making a microneedle array, the apparatus comprising an optical device, a light source, and a microneedle array that comprises a plurality of microneedles with a material coating on at least one microneedle. In a preferred embodiment, the optical device is a 2D array camera. In another embodiment, the light source is a white LED with a collimated lens. The apparatus can optionally include more than one light source and/or optical device.

An additional aspect of the present invention further provides a process for inspecting microneedle arrays comprising illuminating at least a portion of a microneedle array that comprises at least one microneedle with a light source, capturing an observed image of said at least one microneedle using an optical device, electronically processing the observed image, and determining an amount of a material coating on said at least one microneedle.

