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Thiomersal
Thiomersal
IUPAC nameEthyl(2-mercaptobenzoato-(2-)-O,S)
mercurate(1-) sodium
Other namesMercury((o-carboxyphenyl)thio)ethyl sodium salt
Identifiers
CAS number[54-64-8]
EINECS number200-210-4
RTECS numberOV8400000
Properties
Molecular formulaC9H9HgNaO2S
Molar mass404. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to The EINECS number (for European Inventory of Existing Chemical Substances) is a registry number given to each Chemical substance commercially available in the Registry of Toxic Effects of Chemical Substances ( RTECS) is a Database of Toxicity information compiled from the open scientific literature without reference A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Mercury (ˈmɜrkjʊri also called quicksilver or hydrargyrum, is a Chemical element with the symbol Hg ( Latinized hydrargyrum Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 81 g/mol
AppearanceWhite or slightly yellow powder
Density500 kg/m³
Melting point

232–233°C (decomposition)

Solubility in water1000 g/l (20°C)
Hazards
MSDSExternal MSDS
NFPA 704
1
3
1
 
R-phrasesR26/27/28R33R50/53
S-phrasesS13S28S36S45S60S61
Flash point250°C
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Thiomersal (INN) (C9H9HgNaO2S), commonly known in the United States as thimerosal, is an organomercury compound (approximately 49% mercury by weight) used as an antiseptic and antifungal agent. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different The melting point of a solid is the temperature range at which it changes state from solid to Liquid. Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. Water is a common Chemical substance that is essential for the survival of all known forms of Life. A material safety data sheet ( MSDS) is a form containing data regarding the properties of a particular substance Symbolism The four divisions are typically color-coded with blue indicating level of Health Hazard, red indicating R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. The flash point of a flammable liquid is the lowest Temperature at which it can form an ignitable mixture in air In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly An International Nonproprietary Name ( INN; also known as rINN, for recommended International Nonproprietary Name or pINN for proposed Organomercury refers to the group of organometallic compounds that contain mercury. Antiseptics (from Greek αντί - anti, '"against" + σηπτικός - septikos, "putrefactive" are antimicrobial An antifungal drug is Medication used to treat fungal Infections such as Athlete's foot, Ringworm, Candidiasis (thrush

It was developed and registered under the trade name Merthiolate in 1928 by the pharmaceutical corporation Eli Lilly and Company and has been used as a preservative in vaccines, immunoglobulin preparations, skin test antigens, antivenins, ophthalmic and nasal products, and tattoo inks. Eli Lilly and Company ( is a global Pharmaceutical company and one of the world's largest corporations A preservative is a natural or synthetic chemical that is added to products such as foods pharmaceuticals paints biological samples wood etc A vaccine is a biological preparation which is used to establish or improve immunity to a particular disease Antibodies (also known as immunoglobulins, abbreviated Ig) are Gamma globulin Proteins that are found in Blood or other Bodily Allergy is a disorder of the Immune system often also referred to as Atopy. Antivenin (or antivenom or antivenene) is a biological product used in the treatment of venomous bites or stings Ophthalmology is the branch of Medicine which deals with the diseases and surgery of the visual pathways including the Eye, Brain A tattoo is a permanent marking made by inserting ink into the layers of Skin to change the pigment for decorative or other reasons

In the U. S. , the European Union, and a few other affluent countries, the compound is being phased out from vaccines routinely given to children. The European Union ( EU) is a political and economic union of twenty-seven member states, located primarily in [1] Packaging the vaccines in single-dose vials eliminates the need for bacteriostatics such as thiomersal. Bacteriostatic Antibiotics limit the growth of bacteria by interfering with bacterial Protein production DNA replication or other aspects of [2]

Contents

Use

Thiomersal's main use is as an antiseptic and antifungal agent. In multidose injectable drug delivery systems, it prevents serious adverse effects such as the Staphylococcus infection that, in one 1928 incident, killed 12 of 21 children inoculated with a diphtheria vaccine that lacked a preservative. Staphylococcus (in Greek σταφυλη staphyle means bunch of grapes and κοκκος coccos means granule is a genus of Gram-positive Inoculation is the placement of something to where it will grow or reproduce and is most commonly used in respect of the introduction of a serum Vaccine, or antigenic substance Diphtheria ( Greek διφθερα ( diphthera)—“pair of leather scrolls" is an upper respiratory tract illness characterized by sore [3] Unlike other vaccine preservatives used at the time, thiomersal does not reduce the potency of the vaccines that it protects. [4] Thiomersal is not needed in more-expensive single-dose injectables.

In the U. S. , the European Union, and a few other affluent countries, thiomersal is no longer used as a preservative in routine childhood vaccination schedules. A vaccination schedule is a recommended series of Vaccinations including the suggested timing of all doses [1] In the U. S. , the only exceptions among vaccines routinely recommended for children are some formulations of the inactivated influenza vaccine for children older than two years. [5] Several vaccines that are not routinely recommended for young children do contain thiomersal, including DT (diphtheria and tetanus), Td (tetanus and diphtheria), and TT (tetanus toxoid); other vaccines may contain a trace of thiomersal from steps in manufacture. Diphtheria ( Greek διφθερα ( diphthera)—“pair of leather scrolls" is an upper respiratory tract illness characterized by sore Tetanus is a medical condition that is characterized by a prolonged contraction of Skeletal muscle fibres [3] Also, four rarely used treatments for pit viper, coral snake, and black widow venom still contain thiomersal. [6] Outside North America and Europe, many vaccines contain thiomersal; the World Health Organization has concluded that there is no evidence of toxicity from thiomersal in vaccines and no reason on safety grounds to change to more-expensive single-dose administration. [7]

Toxicology

Thiomersal is very toxic by inhalation, ingestion, and in contact with skin (EC hazard symbol T+), with a danger of cumulative effects. Hazard symbols are easily recognizable symbols designed to warn about hazardous materials or locations It is also very toxic to aquatic organisms and may cause long-term adverse effects in aquatic environments (EC hazard symbol N). [8] In the body, it is metabolized or degraded to ethylmercury (C2H5Hg+) and thiosalicylate. Ethylmercury (sometimes ethyl mercury) is a Cation composed of an Ethyl group and a mercury atom its chemical formula is C 2 [3]

Few studies of the toxicity of thiomersal in humans have been performed. Animal experiments suggest that thiomersal rapidly dissociates to release ethylmercury after injection; that the disposition patterns of mercury are similar to those after exposure to equivalent doses of ethylmercury chloride; and that the central nervous system and the kidneys are targets, with lack of motor coordination being a common sign. Similar signs and symptoms have been observed in accidental human poisonings. The mechanisms of toxic action are unknown. Fecal excretion accounts for most of the elimination from the body. Ethylmercury clears from blood with a half-time of about 18 days, and from the brain in about 14 days. Inorganic mercury metabolized from ethylmercury has a much longer clearance, at least 120 days; it appears to be much less toxic than the inorganic mercury produced from mercury vapor, for reasons that are not understood. [9]

Risk assessment for effects on the nervous system have been made by extrapolating from dose-response relationships for methylmercury, which is why thiomersal was removed from U. Methylmercury (sometimes methyl mercury) is an Organometallic Cation with the formula + S. childhood vaccines, starting in 1999. However, since then, it has been found that ethylmercury is cleared from the body and the brain significantly faster than methylmercury, so the late-1990s risk assessments turned out to be overly conservative. [9] A 2008 study found that the half-life of blood mercury after vaccination averages 3. 7 days for newborns and infants, much shorter than the 44 days for methylmercury. [10]

Allergies

Thiomersal is used in patch testing for people who have dermatitis, conjunctivitis, and other potentially allergic reactions. A 2007 study in Norway found that 1. 9% of adults had a positive patch test reaction to thiomersal;[11] a higher prevalence of contact allergy (up to 6. 6%) was observed in German populations. [12] Thiomersal-sensitive individuals can receive intramuscular rather than subcutaneous immunization,[13] so contact allergy is usually clinically irrelevant. Intramuscular injection is the injection of a substance directly into a Muscle. The subcutaneous tissue or subcutis is the layer of Loose connective tissue directly underlying the Dermis. [12] Thiomersal allergy has decreased in Denmark, probably because of its exclusion from vaccines there. [14]

Autism

Main article: Thiomersal controversy

Many parents, and some scientists and doctors, believe there is a connection between thiomersal and autism. The thiomersal controversy is between claims that Thiomersal -containing Vaccines (TCVs cause or contribute to the development of Autism and other Language development. The terminology [15] More than 5,000 U. S. families have filed claims alleging autism was caused by vaccines, most implicating thiomersal; the majority of these claims are still being adjudicated, and no awards have been issued. [15] Although there is no convincing evidence that thiomersal is a factor in the onset of autism, parents may first become aware of autistic symptoms in their child around the time of a routine vaccination, and parental concern about vaccines has led to a decreasing uptake of childhood immunizations and an increasing likelihood of measles outbreaks. Evidence-based medicine (EBM aims to apply Evidence gained from the Scientific method to certain parts of medical practice Vaccination is the administration of Antigenic material (the Vaccine) to produce immunity to a disease A vaccination schedule is a recommended series of Vaccinations including the suggested timing of all doses Measles (rubeola is a Disease caused by a virus specifically a Paramyxovirus of the genus Morbillivirus. [16]

History

Morris S. Kharasch, a chemist at the University of Maryland, filed a patent application for thiomersal in 1927;[17] Eli Lilly was granted the patent for the compound under the trade name Merthiolate in 1928. Morris Selig Kharasch (1895-1957 was a pioneering organic chemist best known for his work with free radical additions and Polymerizations He defined the A chemist is a Scientist trained in the Science of Chemistry. The University of Maryland College Park (often referred to as The University of Maryland UMD, UMCP or simply Maryland) is a public research [4] In vitro tests conducted by Lilly investigators H. In vitro ( Latin: within the glass refers to the technique of performing a given experiment in a controlled environment outside of a living Organism M. Powell and W. A. Jamieson found that it was forty to fifty times as effective as phenol against Staphylococcus aureus. Phenol, is a toxic colourless Crystalline Solid with a sweet tarry odor commonly referred to as a "hospital smell" Staphylococcus aureus (ˌstæfɨləˈkɒkəs ˈɔriəs literally "Golden Cluster Seed" and also known as golden staph) is the most common cause of [4] It was used to kill bacteria and prevent contamination in antiseptic ointments, creams, jellies, and sprays used by consumers and in hospitals, including nasal sprays, eye drops, contact lens solutions, immunoglobulins, and vaccines. Thiomersal was used as a preservative (bactericide) so that multidose vials of vaccines could be used instead of single-dose vials, which are more expensive. A bactericide or bacteriocide is a substance that kills bacteria and preferably nothing else By 1938, Lilly's assistant director of research listed thiomersal as one of the five most important drugs ever developed by the company. [4]

Thiomersal's safety for its intended uses first came under question in the 1970s, when case reports demonstrated potential for neurotoxicity when given in large volumes as a topical antiseptic. At the time, the DPT vaccine was the only childhood vaccine that contained it; a 1976 FDA review concluded that this use of thiomersal was not dangerous. DPT, (sometimes DTP) is a mixture of three Vaccines to immunize against Diphtheria, Pertussis (whooping cough and Tetanus. [4] Concerns about mercury arising from Minamata disease and other cases of methylmercury poisoning led U. sometimes referred to as, is a neurological syndrome caused by severe Mercury poisoning. Methylmercury (sometimes methyl mercury) is an Organometallic Cation with the formula + S. authorities to lower reference doses for methylmercury in the 1990s, about the same time that autism diagnoses began rising sharply. In 1999, a new FDA analysis concluded that infants could receive as much as 187. 5 mg of ethylmercury during the first six months; lacking any standard for ethylmercury, it used methylmercury-based standards to recommend that thiomersal be removed from routine childhood vaccines in the U. S. , which was done by 2001. [4] Some parents of autistic children adopted thiomersal as an explanation for the increase in reported autism cases and sued vaccine makers; the mercury-autism hypothesis is accepted widely among parents of autistic children, despite scientific studies rejecting it. [4]

References

  1. ^ a b Bigham M, Copes R (2005). "Thiomersal in vaccines: balancing the risk of adverse effects with the risk of vaccine-preventable disease". Drug Saf 28 (2): 89–101. PMID 15691220.  
  2. ^ Thimerosal in Vaccines: Frequently Asked Questions, from the United States Food and Drug Administration. Accessed March 9, 2008. Events 590 - Bahram Chobin is crowned as king Barham VI of Persia. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common
  3. ^ a b c Thimerosal in vaccines. Center for Biologics Evaluation and Research, U. S. Food and Drug Administration (2007-09-06). Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 3114 BC - According to the Proleptic Julian calendar the current era in the Maya Long Count Calendar started Retrieved on 2007-10-01. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 331 BC - Alexander the Great defeats Darius III of Persia in the Battle of Gaugamela.
  4. ^ a b c d e f g Baker JP (2008). "Mercury, vaccines, and autism: one controversy, three histories". Am J Public Health 98 (2): 244–53. doi:10.2105/AJPH.2007.113159. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 18172138.  
  5. ^ Coordinating Center for Infectious Diseases (2007-10-26). Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 740 - An Earthquake strikes Constantinople, causing much damage and death Thimerosal in seasonal influenza vaccine. Centers for Disease Control and Prevention. Retrieved on 2008-04-02. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 68 - Galba, Governor of Hispania, names himself legatus senatus populique Romani, breaking the line of
  6. ^ Mercury in plasma-derived products. U. S. Food and Drug Administration (2004-09-09). "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Events 1000 - Battle of Svolder, Viking Age. 1379 - Treaty of Neuberg, splitting the Austrian Retrieved on 2007-10-01. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 331 BC - Alexander the Great defeats Darius III of Persia in the Battle of Gaugamela.
  7. ^ Global Advisory Committee on Vaccine Safety (2006-07-14). Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1223 - Louis VIII becomes King of France upon the death of his father Philip II of France. Thiomersal and vaccines. World Health Organization. Retrieved on 2007-11-20. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 284 - Diocletian was chosen as Roman Emperor. 762 - Bögü Khan of the Uyghurs,
  8. ^ Thiomersal Ph Eur, BP, USP material safety data sheet (PDF). Merck (2005-06-12). Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Events 1381 - Peasants' Revolt: in England, rebels arrive at Blackheath. Retrieved on 2007-10-01. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 331 BC - Alexander the Great defeats Darius III of Persia in the Battle of Gaugamela.
  9. ^ a b Toxicology of thiomersal:
  10. ^ Pichichero ME, Gentile A, Giglio N et al. (2008). "Mercury levels in newborns and infants after receipt of thimerosal-containing vaccines". Pediatrics 121 (2): e208–14. doi:10.1542/peds.2006-3363. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 18245396. Lay summary – University of Rochester Medical Center (2008-01-30). 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1648 - Eighty Years' War: The Treaty of Münster is signed ending the conflict between the Netherlands and Spain  
  11. ^ Dotterud LK, Smith-Sivertsen T (2007). "Allergic contact sensitization in the general adult population: a population-based study from Northern Norway". Contact Dermatitis 56 (1): 10–5. doi:10.1111/j.1600-0536.2007.00980.x. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 17177703.  
  12. ^ a b Uter W, Ludwig A, Balda BR (2004). "The prevalence of contact allergy differed between population-based and clinic-based data". J Clin Epidemiol 57 (6): 627–32. doi:10.1016/j.jclinepi.2003.04.002. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 15246132.  
  13. ^ Aberer W (1991). "Vaccination despite thimerosal sensitivity". Contact Dermatitis 24 (1): 6–10. doi:10.1111/j.1600-0536.1991.tb01621.x. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 2044374.  
  14. ^ Thyssen JP, Linneberg A, Menné T, Johansen JD (2007). "The epidemiology of contact allergy in the general population—prevalence and main findings". Contact Dermatitis 57 (5): 287–99. doi:10.1111/j.1600-0536.2007.01220.x. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 17937743.  
  15. ^ a b Sugarman SD (2007). "Cases in vaccine court—legal battles over vaccines and autism". N Engl J Med 357 (13): 1275–7. doi:10.1056/NEJMp078168. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 17898095.  
  16. ^ Vaccines and autism:
    • Thimerosal in vaccines. Center for Biologics Evaluation and Research, U. S. Food and Drug Administration (2008-03-14). 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1489 - The Queen of Cyprus, Catherine Cornaro, sells her kingdom to Venice. Retrieved on 2008-03-21. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 630 - Byzantine emperor Heraclius restores the True Cross to Jerusalem.
    • Doja A, Roberts W (2006). "Immunizations and autism: a review of the literature". Can J Neurol Sci 33 (4): 341–6. PMID 17168158.  
    • Taylor B (2006). "Vaccines and the changing epidemiology of autism". Child Care Health Dev 32 (5): 511–9. doi:10.1111/j.1365-2214.2006.00655.x. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 16919130.  
  17. ^ US patent 1672615
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