Intradermal insulin delivery: a promising future for diabetes management

Abstract

The incidence of insulinopenic diabetes mellitus is constantly increasing, and in addition, approximately a third of all hyperinsulinemic diabetic patients develop insulinopenia. Optimal glycemic control is essential to minimize the risk for diabetes-induced complications, but the majority of diabetic patients fail to achieve proper long-term glucose levels even in clinical trials, and even more so in clinical practice. Compliance with a treatment regimen is likely to be higher if the procedure is simple, painless, and discreet. Thus, insulin has been suggested for nasal, gastrointestinal, and inhalation therapy, but so far with considerable downsides in effect, side effects, or patient acceptance. The stratum corneum is the main barrier preventing convenient drug administration without the drawbacks of subcutaneous injections. Recently, devices with miniaturized needles have been developed that combine the simplicity and discretion of patch-based treatments, but with the potential of peptide and protein administration. As this review describes, initial comparisons with subcutaneous administration now suggest microneedle patches for active insulin delivery are efficient in maintaining glycemic control. Hollow microneedle technology could also prove to be efficient in systemic as well as local delivery of other macromolecular drugs, such as vaccines.

Keywords: diabetes; hollow; insulin; intradermal; microneedles; transdermal.

Figure 1.

Schematic illustration depicting a cross section of the skin, with epidermis, dermis, and subcutaneous tissue.

Figure 2.

Scanning electron microscopy picture showing a complete microneedle device displayed next to 2 standard 20 G and 27 G syringes.

Figure 3.

Photomicrograph showing a pattern in the skin of a human subject after dye injection through the patch-like microneedle device.

Figure 4.

Schematic overview of a Micro-Electro-Mechanical System (MEMS) device.