THERAPEUTIC HORMONES TOWARDS HUMAN SYSTEM

Insulin was first used as a medication in Canada by Charles Best and Frederick Banting in January 1922.

Insulin (medication) is the use of insulin and similar proteins as a medication to treat disease.

Insulin is used to treat a number of diseases including diabetes and its acute complications such as diabetic ketoacidosis and hyperosmolar hyperglycaemic states. It is also used along with glucose to treat high blood potassium levels.

Side effects may include: low blood sugar levels, skin reactions at the site of injection and low potassium levels among others.

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Types of Insulin

?Choosing insulin type and dosage/timing should be done by an experienced medical professional working closely with the diabetic patient. The commonly used types of insulin are:

Fast-acting: Includes the insulin analogues aspart, lispro, and glulisine. These begin to work within 5 to 15 minutes and are active for 3 to 4 hours.

Short-acting: Includes regular insulin which begins working within 30 minutes and is active about 5 to 8 hours.

Intermediate-acting: Includes NPH insulin which begins working in 1 to 3 hours and is active 16 to 24 hours.

Long acting: Includes the analogues glargine and detemir, each of which begins working within 1 to 2 hours and continue to be active, without major peaks or dips, for about 24 hours, although this varies in many individuals.

Ultra-long acting: Currently only includes the analogue degludec, which begins working within 30–90 minutes, and continues to be active for greater than 24 hours.

Combination insulin products : Includes a combination of either fast-acting or short-acting insulin with a longer acting insulin, typically an NPH insulin. The combination products begin to work with the shorter acting insulin (5–15 minutes for fast-acting, and 30 minutes for short acting), and remain active for 16 to 24 hours. There are several variations with different proportions of the mixed insulins.

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?Methods of administration

?Unlike many medicines, insulin cannot be taken orally at the present time. Like nearly all other proteins introduced into the gastrointestinal tract, it is reduced to fragments? whereupon all 'insulin activity' is lost.

i)???Subcutaneous- Insulin is usually taken as subcutaneous injections by single-use syringes with needles, an insulin pump, or by repeated-use insulin pens with needles. Patients who wish to reduce repeated skin puncture of insulin injections often use an injection port in conjunction with syringes.

?ii) Insulin pump- Insulin pumps are a reasonable solution for some. Advantages to the patient are better control over background or 'basal' insulin dosage, bolus doses calculated to fractions of a unit, and calculators in the pump that may help with determining 'bolus' infusion dosages. The limitations are cost, the potential for hypoglycemic and hyperglycaemic episodes, catheter problems, and no "closed loop" means of controlling insulin delivery based on current blood glucose levels. Insulin pumps may be like 'electrical injectors' attached to a temporarily implanted catheter or cannula.

??iii)?? Inhalable insulin- In 2006 the U.S. Food and Drug Administration approved the use of Exubera, the first inhalable insulin. It was withdrawn from the market by its maker as of third quarter 2007, due to lack of acceptance. Inhaled insulin claimed to have similar efficacy to injected insulin, both in terms of controlling glucose levels and blood half-life. Currently, inhaled insulin is short acting and is typically taken before meals; an injection of long-acting insulin at night is often still required. When patients were switched from injected to inhaled insulin, no significant difference was observed in HbA1c levels over three months. Accurate dosing was a particular problem, although patients showed no significant weight gain or pulmonary function decline over the length of the trial, when compared to the baseline.

?iv)??Transdermal- There are several methods for transdermal delivery of insulin. Pulsatile insulin uses microjets to pulse insulin into the patient, mimicking the physiological secretions of insulin by the pancreas. Jet injection had different insulin delivery peaks and durations as compared to needle injection. The insulin administration aspect remains experimental, but the blood glucose test aspect of "wrist appliances" is commercially available. Researchers have produced a watch-like device that tests for blood glucose levels through the skin and administers corrective doses of insulin through pores in the skin.

??v)?? Oral insulin- The basic appeal of oral hypoglycemic agents is that most people would prefer a pill to an injection. However, insulin is a protein, which is digested in the stomach and gut and in order to be effective at controlling blood sugar, cannot be taken orally in its current form. The potential market for an oral form of insulin is assumed to be enormous, thus many laboratories have attempted to devise ways of moving enough intact insulin from the gut to the portal vein to have a measurable effect on blood sugar.

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?Detection in biological fluids

?Insulin is often measured in serum, plasma or blood in order to monitor therapy in diabetic patients, confirm a diagnosis of poisoning in hospitalized persons or assist in a medicolegal investigation of suspicious death. Interpretation of the resulting insulin concentrations is complex, given the numerous types of insulin available, various routes of administration, the presence of anti-insulin antibodies in insulin-dependent diabetics and the ex vivo instability of the drug.

?Combination with another antidiabetic drug

?A combination therapy of insulin and other antidiabetic drugs appears to be most beneficial in diabetic patients who still have residual insulin secretory capacity. A combination of insulin therapy and sulphonyl urea is more effective than insulin alone in treating patients with type 2 diabetes after secondary failure to oral drugs, leading to better glucose profiles and/or decreased insulin needs.

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Allergy

?Allergy to Insulin products is rare with a prevalence of about 2%, of which most reactions are not due to the insulin itself but to preservatives added to insulin such as zinc, protamine, and meta-cresol. Most reactions are Type I hypersensitivity reactions and rarely cause anaphylaxis. A suspected allergy to insulin can be confirmed by skin prick testing, patch testing and occasionally skin biopsy. First line therapy against insulin hypersensitivity reactions includes symptomatic therapy with antihistamines.

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?Problems associated with insulin

?There are several problems with insulin as a clinical treatment for diabetes:

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? Mode of administration.

? Selecting the 'right' dose and timing.

? Selecting an appropriate insulin preparation

? Adjusting dosage and timing to fit food intake timing, amounts, and types.

Adjusting dosage and timing to fit exercise undertaken.

? Adjusting dosage, type, and timing to fit other conditions, for instance the increased stress of illness.

? It is simply a nuisance for patients to inject whenever they eat carbohydrate or have a high blood glucose reading

It is dangerous in case of mistake.

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Thanks and Regards,

Amita Rao

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