Insulin: The journey continues

In the history of medicine, the discovery of insulin marked a turning point. At first, the only form of insulin that could be administered to humans was this secretion from animal pancreas. Since its conception, technologies for purifying and altering insulin have been developed, although they are still a long way from simulating pancreatic-cells' natural production. The precise structure of the insulin molecule had been uncovered by the late 1950s, and with the development of molecular biology and recombinant DNA techniques, it is now feasible to manipulate genes to produce recombinant human insulins. This opened the door for the creation of short-acting analogs to mimic postprandial insulin secretion and long-acting analogs to mimic basal or background insulin secretion. The patients can more closely mimic pancreatic insulin secretion thanks to the characteristics of the new basal and bolus analogs than they could with the earlier insulins. However, there are still issues with the absence of portal delivery, night-time dip, morning surge, and responsiveness to ambient blood glucose. There are a number of noninvasive methods being researched for the delivery of insulin, including transdermal, buccal, oral, and pulmonary routes. The hunt for insulin that precisely mirrors the physiological profile and has improved stability, less variability, and perhaps selective action, is still ongoing.