Lugol's iodine

Lugol's iodine, also known as Lugol's solution, first made in 1829, is a solution of iodine named after the French physician J.G.A. Lugol. Lugol's iodine solution is often used as an antiseptic and disinfectant, a starch indicator, to replenish iodine deficiency, to protect the thyroid gland from radioactive materials (e.g. "fallout"), and for emergency disinfection of drinking water.^[1]

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Lugol's was often used in the treatment of gout and was used as a first line treatment for hypothyroidism in adults.

It consists of 5% iodine (I₂) and 10% potassium iodide (KI) in 85% distilled water with a total iodine content of 130 mg/mL. Potassium iodide makes the iodine water soluble through the formation of the I₃^- ion. It is obtained from chemists and pharmacists who are licensed to prepare and dispense the solution.

This solution is also used as an indicator to test for the presence of starches in organic compounds, with which it reacts by turning a dark-blue/black. IKI will stain starches due to its interaction with the coil structure of the polysaccharide. IKI solution will not detect simple sugars such as glucose or fructose. In the pathologic condition amyloidosis, amyloid deposits can be so abundant that affected organs will also stain grossly positive for the Lugol reaction for starch. Other names for Lugol's solution are IKI (Iodine Potassium-Iodide); Iodine, Strong solution (Systemic); Aqueous Iodine Solution BP.

It can be used as a cell stain, making the cell nuclei more visible and for preserving phytoplankton samples.

During colposcopy, Lugol's iodine is applied to the vagina and cervix. Normal tissue stains brown, while tissue suspicious for cancer does not stain, and appears pale compared to the surrounding tissue. Biopsy of suspicious tissue can then be performed. This is called Schiller's test.

Applications

Historically, Lugol's iodine solution has been widely available and used for a number of health problems with some precautions.^[2] Lugol's is sometimes prescribed in a variety of alternative medical treatments.^[3][4]

In the United States of America, Lugol's solution was previously unregulated and available over the counter as a general reagent, an antiseptic, a preservative,^[5] or as a medicament for human or veterinary application. However, effective August 1, 2007, the DEA now regulates Lugol's solution (and, in fact, all iodine solutions containing greater than 2.2% iodine) as a List I precursor because it may potentially be used in the illicit production of methamphetamine.^[6] By contrast, Lugol's iodine solution is available over the counter in Canada and Mexico, for example.

Following the Chernobyl nuclear reactor disaster in April, 1986, Lugol's iodine solution was administered to 10.5 million children and 7 million adults in Poland^[7] as a prophylactic measure against accumulation of radioactive iodine-131 in the thyroid.

Lugol's solution can also be used in various experiments to observe how a cell membrane uses osmosis and diffusion.

References

1. ^ [1] Higdon, J., "Micronutrient Information Center: Iodine," Linux Pauling Institute/Oregon State University; April, 2003 (revised by Drake, V.J., July, 2007).
2. ^ [2] Drugs.com, "Lugol's Solution."
3. ^ [3] Optimox.com, "Iodine."
4. ^ [4] Jcrows.com, "Iodine."
5. ^ [5] Hawkins et al., "Change in cyanobacterial biovolume due to preservation by Lugol's Iodine," Harmful Algae, Volume 4, Issue 6, pp. 1033-1043; November, 2005.
6. ^ [6] US DEA, "Final Rule: Changes in the Regulation of Iodine Crystals and Chemical Mixtures Containing Over 2.2 Percent Iodine," Federal Register, Volume 72, Number 126; July 2, 2007 (FR Doc E7-12736).
7. ^ [7] US FDA, "Potassium Iodide as a Thyroid Blocking Agent in Radiation Emergencies," U.S. Department of Health and Human Services Food and Drug Administration Center for Drug Evaluation and Research (CDER); December, 2001.

See also

• Tincture of iodine
• Betadine

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