Thimerosal

Part of speech: noun

Definitions

1. A mercury-containing agent that serves to preserve vaccines and medical products A substance that prevents microbial contamination in specific medicinal formulations by utilizing a mercury derivative An ethylmercury-based compound used for ensuring the stability and effectiveness of certain pharmaceuticals
2. A compound containing mercury used to prevent bacterial growth in vaccines and other medicinal products
3. A substance including ethylmercury that helps maintain the sterility of specific pharmaceutical items

Etymology: Thimerosal was developed in the 1920s by the Lilly company, which needed a mercury-based preservative that could be dissolved in water and kept sterile vials free of bacteria. Its name is a patchwork of pharmaceutical building blocks rather than a single word with a long history: "thio-" refers to sulfur, which is present in the molecule, "-mer-" marks a mercury-containing drug, and "-sal" points to a salicylic acid derivative, a family of compounds traditionally linked to the chemistry of aspirin-like drugs. The American spelling "thimerosal" is the standard form in the United States, while the older "thiomersal" remains the usual spelling in Britain and elsewhere. The two spellings name the same compound, so the difference is one of regional convention rather than meaning.