Human Insulin

Human Insulin, also known as Regular Insulin, is a short-acting form of insulin used for the treatment of hyperglycemia caused by Type 1 and Type 2 Diabetes. Human insulin is produced by recombinant DNA technology and is identical to endogenously produced insulin. Typically prescribed for the management of diabetes mellitus, insulin is a peptide hormone produced by beta cells of the pancreas that promotes glucose metabolism. Insulin is released from the pancreas following a meal to promote the uptake of glucose from the blood into internal organs and tissues such as the liver, fat cells, and skeletal muscle. Absorption of glucose into cells allows for its transformation into glycogen or fat for storage. Insulin also inhibits hepatic glucose production, enhances protein synthesis, and inhibits lipolysis and proteolysis among many other functions. Insulin is an important treatment in the management of Type 1 Diabetes (T1D) which is caused by an autoimmune reaction that destroys the beta cells of the pancreas, resulting in the body not being able to produce or synthesize the insulin needed to manage circulating blood sugar levels. As a result, people with T1D rely primarily on exogenous forms of insulin to lower glucose levels in the blood. Insulin is also used in the treatment of Type 2 Diabetes (T2D), another form of diabetes mellitus that is a slowly progressing metabolic disorder caused by a combination of genetic and lifestyle factors that promote chronically elevated blood sugar levels. Without treatment or improvement in non-pharmacological measures such as diet and exercise to lower blood glucose, high blood sugar eventually causes cellular resistance to endogenous insulin, and in the long term, damage to pancreatic islet cells. Insulin is typically prescribed later in the course of T2D, after trying several oral medications such as [DB00331], [DB01120], or [DB01261] have been tried, when sufficient damage has been caused to pancreatic cells that the body is no longer able to produce insulin on its own. Marketed as the brand name product Humulin R or Novolin R, human insulin begins to exert its effects within 30 minutes of subcutaneous administration, while peak levels occur 3-4 hours after administration. Due to its quick onset of action, human insulin is considered “bolus insulin” as it provides high levels of insulin in a short period of time to mimic the release of endogenous insulin from the pancreas after meals. Bolus insulin is often combined with once daily, long-acting “basal insulin” such as [DB01307], [DB09564], and [DB00047] to provide low concentrations of background insulin that can keep blood sugar stable between meals or overnight. Use of basal and bolus insulin together is intended to mimic the pancreas’ production of endogenous insulin, with a goal of avoiding any periods of hypoglycemia. Human insulin is also available in an inhalable form, intended to be used as a bolus meal-time insulin. Exubera was the first inhaled insulin available on the market and was developed by Inhale Therapeutics (later named Nektar Therapeutics). Unfortunately, limited uptake by physicians and patients, poor sales, bulky packaging, and concerns over the possible impact on lung cancer development resulted in Exubera products being withdrawn from the US markets. Exubera was followed by Afrezza, a monomeric inhaled insulin developed by Mannkind Corporation, which received FDA approval in 2016. While still available in the US, Afrezza has had similar concerns associated with its use, and had an FDA “black box” warning added to it to warn about use in patients with chronic lung disease. Afrezza does not currently have Health Canada or European Medicines Agency approval for marketing in Canada or the EU. Human Insulin is a 51 residue peptide hormone produced by recombinant DNA technology by inserting the human insulin gene into Escherichia coli bacteria or Saccharomyces cerevisiae. The structure is identical to native human insulin, with two amino acid chains covalently linked by disulfide bonds. Human insulin is also available in an intermediate-acting form as NPH (Neutral Protamine Hagedorn) as the marketed products Novolin N and Humulin N. NPH insulin is provided as a crystalline suspension of insulin with protamine and zinc, resulting in an onset of action in 1 to 3 hours, duration of action up to 24 hours, and peak action from 6 to 8 hours. Due to the added crystals, NPH insulin is typically cloudy when compared to other forms of insulin and has a neutral pH. Without an adequate supply of insulin to promote absorption of glucose from the bloodstream, blood sugar levels can climb to dangerously high levels and can result in symptoms such as fatigue, headache, blurred vision, and increased thirst. If left untreated, the body starts to break down fat, instead of glucose, for energy which results in a build-up of ketone acids in the blood and a syndrome called ketoacidosis, which is a life-threatening medical emergency. In the long term, elevated blood sugar levels increase the risk of heart attack, stroke, and diabetic neuropathy.