Lugol's iodine

Lugol's Iodine, also known as Lugol's Solution, first made in 1829, is a solution of elemental iodine and potassium iodide in water, named after the French physician J.G.A. Lugol. Lugol's iodine solution is often used as an antiseptic and disinfectant, for emergency disinfection of drinking water, and as a reagent for starch detection in routine laboratory and medical tests. These uses are possible since the solution is a source of effectively free elemental iodine, which is readily generated from the equilibrium between elemental iodine molecules and triiodide ion in the solution.[1]

Lugol's Solution has been used traditionally to replenish iodine deficiency.[2] Likewise, in the Chernobyl disaster some Lugol's solution was used as an emergency source of iodide to block radioactive iodine uptake, simply because it was widely available as a drinking water decontaminant, and pure potassium iodide without iodine (the preferred agent) was not available.

Since the 1970s Lugol's Solution has been available in tablet form, generally buffered. However, compounding chemists (pharmacists) had probably been creating tablets containing Lugol's Solution since the early 1900s. The tablet form is generally known as Iodoral.

Applications

Historical applications

Lugol's was often used in the treatment of gout.

It was also used at one time as a first line treatment for hyperthyroidism, as the administration of pharmacologic amounts of iodine leads to temporary inhibition of iodine organification in the thyroid gland, a phenomenon called the Wolff-Chaikoff effect. However it is not used to treat certain autoimmune causes of thyroid disease as iodine-induced blockade of iodine organification may result in hypothyroidism. They are not considered as a first line therapy because of possible induction of resistant hyperthyroidism but may be considered as an adjuvant therapy when used together with other hyperthyroidism medications.

Because of its wide availability as a drinking-water decontaminant, and high content of potassium iodide, emergency use of it was at first recommended to the Polish government in 1986, after the Chernobyl disaster to replace and block any intake of radioactive 131
I
, even though it was known to be a non-optimal agent, due to its somewhat toxic free-iodine content.[6] Other sources state that pure potassium iodide solution in water (SSKI) was eventually used for most of the thyroid protection after this accident.[7] There is "strong scientific evidence" for potassium iodide thyroid protection to help prevent thyroid cancer. Potassium iodide does not provide immediate protection but can be a component of a general strategy in a radiation emergency.[8]

Historically, Lugol's iodine solution has been widely available and used for a number of health problems with some precautions.[9] Lugol's is sometimes prescribed in a variety of alternative medical treatments.[10][11] Only since the end of the Cold War has the compound become subject to national regulation in the Anglosphere.

National regulation

Until 2007, in the United States, Lugol's solution was unregulated and available over the counter as a general reagent, an antiseptic, a preservative,[12] or as a medicament for human or veterinary application.

Since August 1, 2007, the DEA regulates Lugol's solution (and 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.[13] Transactions of up to one fluid ounce (30 ml) of Lugol's solution are exempt from this regulation.

Toxicity

Because it contains free iodine, Lugol's solution at 2% or 5% concentration without dilution is irritating and destructive to mucosa, such as the lining of the esophagus and stomach.

Doses of 10 mL of undiluted 5% solution have been reported to cause gastric lesions when used in endoscopy.[14] The LD50 for Iodine is 14,000 mg/kg [Rat] and 22,000 mg/kg [Mouse].[15]

Most guidelines accept that anything with an LD50 >2 g/kg (or 3-5 g/kg in some countries) can be classed as having a low acute toxicity which classifies Iodine as having low toxicity. Potassium Iodide is not considered hazardous.[16]

See also

General topic

Forms of Iodine

Reagents

References

  1. Turner, Douglas; Flynn, George; Sutin, Norman; Beitz, James (March 1972). "Laser Raman temperature-jump study of the kinetics of the triiodide equilibrium. Relaxation times in the 10-8 -10-7 second range". J. Am. Chem. Soc. 94 (5): 1554–1559. doi:10.1021/ja00760a020. Retrieved 16 November 2015.
  2. Higdon, J. (April, 2003) "Micronutrient Information Center: Iodine," Linus Pauling Institute/Oregon State University (revised by Drake, V.J., July, 2007).
  3. Han, J. Changes in Gingival Dimensions Following Connective Tissue Grafts for Root Coverage: Comparison of Two Procedures. J Perio 2008;79:1346-1354.
  4. Erbil Y, Ozluk Y, Giriş M, et al. (June 2007). "Effect of lugol solution on thyroid gland blood flow and microvessel density in the patients with Graves' disease". J. Clin. Endocrinol. Metab. 92 (6): 2182–9. doi:10.1210/jc.2007-0229. PMID 17389702.
  5. Kaur S, Parr JH, Ramsay ID, Hennebry TM, Jarvis KJ, Lester E (May 1988). "Effect of preoperative iodine in patients with Graves' disease controlled with antithyroid drugs and thyroxine". Ann R Coll Surg Engl 70 (3): 123–7. PMC 2498739. PMID 2457351.
  6. Rotkiewicz, Marcin; Henryk Suchar; Ryszard Kamiñski (14 January 2001). "Chernobyl: the Biggest BLUFF of the 20th Century". Polish weekly Wprost. pp. no 2. Retrieved 2008-06-18.
  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.
  8. "Iodine." MedlinePlus.
  9. Drugs.com, "Lugol's Solution"
  10. Optimox.com, "Iodine"
  11. Jcrows.com, "Iodine"
  12. Hawkins; et al. (2005). "Change in cyanobacterial biovolume due to preservation by Lugol's Iodine". Harmful Algae 4 (6): 1033–1043. doi:10.1016/j.hal.2005.03.001.
  13. US DEA, "Final Rule: Changes in the Regulation of Iodine Crystals and Chemical Mixtures Containing Over 2.2 Percent Iodine" (July 2, 2007) Federal Register, Volume 72, Number 126 (FR Doc E7-12736)
  14. Sreedharan et al. (June 2005). "Acute toxic gastric mucosal damage induced by Lugol’s iodine spray during chromoendoscopy". Gut 54 (6): 886–887. doi:10.1136/gut.2004.061739. PMC 1774547. PMID 15888800.
  15. Sciencelab.com
  16. Esciencelabs.com
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