Merbromin's best-known use is as a topical antiseptic to treat minor wounds, burns, and scratches. It is also used in the antisepsis of the umbilical cord and the antisepsis of wounds with inhibited scar formation, such as neuropathic ulcers and diabetic foot sores. When applied on a wound, it stains the skin a distinctive carmine red, which can persist up to two weeks through repeated washings. It is useful on infections of the finger or toe nails because of its permanence and lethality to bacteria. The U.S. Food and Drug Administration in 1998 classified merbromin as not generally recognized as safe due to a lack of recent studies and updated supporting information, not due to evidence of toxicity. In the United States, its use has been superseded by other agents. Merbromin is also used as a biological dye to mark tissue margins and as a metal dye in industrial dye penetrant inspection to detect metal fractures.
Synthesis
Merbromin is synthesized by combining dibromofluorescein with mercuric acetate and sodium hydroxide or alternatively, through action of the mercuric acetate upon sodium dibromofluorescein. Because of its anionic character, it is chemically incompatible with acids, the majority of alkaloid salts and most local anesthetics.
Mercurochrome
Merbromin is sold under the trade name Mercurochrome. The name is also commonly used for over-the-counter antiseptic solutions consisting of merbromin dissolved in either ethyl alcohol or water. Its antiseptic qualities were discovered in 1918 by Hugh H. Young, a physician at Johns Hopkins Hospital. The chemical soon became popular among parents and physicians for everyday antiseptic uses, including minor schoolyard injuries. It was commonly referred to as "monkey blood," referring to its deep red color. On, citing potential for mercury poisoning, the Food and Drug Administration reclassified merbromin from "generally recognized as safe" to "untested," effectively halting its distribution within the United States. Sales were subsequently halted in Brazil, Germany, and France. It is readily available in most other countries. Within the United States, products such as Humco Mercuroclear play on the brand recognition history of Mercurochrome but substitute other ingredients with similar properties. In Canada, Jean Coutu Group markets a chlorhexidinesolution under the name Mercurochrome.
