Transdermal delivery or delivery though the outer layer of skin, is a commonly used technique for administering a number of therapeutic substances. Nicotine and hormone replacement patches or simple topically applied lotions are widely used examples. The active pharmaceutical ingredient – or API – is held close to the skin and through natural or aided diffusion travels across the barrier deeper into the skin or even into the blood stream over time. In some cases this slow release is required but in a majority of possible applications this is a significant disadvantage often rendering treatments ineffective with successive applications over longer periods. Indeed, some API's are too big to be used in this way.
To greatly enhance the delivery, effectiveness and choice of commonly used API's a microneedle based solution can be employed. The surface of a substrate or material can be coated with very precise tiny "pin-like" structures which, when applied to the skin can puncture the dead outer layer(stratum corneum) creating a "pore" or "micro-channel" that allows rapid diffusion of the API. This is painless and depth of penetration carefully controlled.
Diagrammatic representation of the measurements of MN penetration into skin, namely the distance between the lower MN base plate or substrate and the stratum corneum (a), the depth of MN penetration into the skin (b) and the width of the pore created in the skin (c).
By manipulating our microneedle characteristics we can affect different delivery mechanisms on the dermis when applied. Multiplepotential needle structural variations are easily achieved through Innoture’s manufacturing technique. These can affect pore or micro-channel openings at the surface of the dermis along with permeation or absorbance profile of the API being delivered, making possible rapid solutions to existing or potential drug treatments.
To date a variety of materials have been investigated and used in our production process. The materials described below are either currently in use or have been tested and deemed appropriate for use. These materials have been identified as part of the ongoing R&D at Innoture and developed in-line with existing applications and clinical trials. Varying applications may require the use of different materials with alternate properties optimized to ensure the most effective system is created.
Whilst microneedles are limited by their ability to easily form and maintain a functional structure the substrates employed can be more widely varied, as long as the pillar forming material can adhere to the substrate and retain its functional structure. Again, we must highlight that desired application specific effects must be taken into consideration when choosing a substrate or using an identified substrate as part of an existing product or process. Innoture, in conjunction with a specialist manufacturer, has examined a range of substrates , developed with specific applications in mind, and compatible for human use.
Innoture’s technology is uniquely versatile in that it is capable of solving scaled application modalities easily permitting the formation of microneedles on any size substrate areas from finger tips to torso. Importantly the patented technology allows Innoture to gear any solution to large scale extremely low cost manufacturing.
To date, Innoture has carefully chosen its component materials to be as compliant with regulations as possible. For its own R&D Innoture has ensured the adoption of existing, approved and in-current-use materials by the medical industry including approvals by the MHRA and FDA. This was driven by the need to examine human orientated medical applications and the associated regulatory mechanism that governs this area. Sterility of the product can be controlled by manufacture in a clean environment and the materials previously outlined are suitable for irradiation.
Innoture welcome the opportunity to work with collaborators and other industry partners in the adaptation.