Diabetes mellitus, an endocrine disorder affecting glucose metabolism, has been crippling mankind for the past
two centuries. Despite the advancements in the understanding pertaining to its pathogenesis and treatment, the currently
available therapeutic options are far from satisfactory. The growing diabetic population increases the gravity of the situation.
The shortcomings of the conventional drug delivery systems necessitate the need to delve into other routes. On account
of its merits over other routes, the transdermal approach has drawn the interest of the researchers around the world.
The transdermal drug delivery systems are aimed to achieve therapeutic concentrations of the drug through skin. These
systems are designed so that the drug can be delivered at a pre-determined and controlled rate. This makes it particularly
conducive to treat chronic disorders like diabetes. Correspondingly, the adverse effects and inconvenience concomitant
with oral and parentral route are circumvented. This article attempts to outline the development of transdermal drug delivery
systems to optimize diabetes pharmacotherapy. It not only covers the transdermal approaches adopted to fine-tune insulin
delivery, but also, discusses various transdermal drug delivery systems fabricated to improve the therapeutic performance
of oral hypoglycaemic agents. Such formulations include the advanced drug delivery systems, namely, transferosomal
gels, microemulsions, self-dissolving micropiles, nanoparticles, insulin pumps, biphasic lipid systems, calcium
carbonate nanoparticles, lecithin nanoparticles; physical techniques such as iontophoresis and microneedles and, drugs
formulated as transdermal patches. In addition to this, the authors have also shed light on the future prospects and patented
and commercial formulations of antidiabetic agents.