World Library  
Flag as Inappropriate
Email this Article

Thiomersal

 

Thiomersal

Thiomersal
Thiomersal
Names
IUPAC name
Ethyl(2-mercaptobenzoato-(2-)-O,S) mercurate(1-) sodium
Other names
Mercury((o-carboxyphenyl)thio)ethyl sodium salt
Identifiers
 Y
ATC code D08
ChEBI  Y
ChEMBL  Y
ChemSpider  Y
EC number 200-210-4
Jmol-3D images Image
PubChem
RTECS number OV8400000
UNII  Y
Properties
C9H9HgNaO2S
Molar mass 404.81 g/mol
Appearance White or slightly yellow powder
Density 2.508 g/cm3[1]
Melting point 232 to 233 °C (450 to 451 °F; 505 to 506 K)
1000 g/l (20 °C)
Hazards
Safety data sheet External MSDS
Very toxic (T+)
Dangerous for the environment (N)
Repr. Cat. 1
R-phrases R50/53 R60 R61
S-phrases S13 S28 S36 S45 S53 S60 S61
NFPA 704
1
3
1
Flash point 250 °C (482 °F; 523 K)
Lethal dose or concentration (LD, LC):
LD50 (Median dose)
75 mg/kg (oral, rat)[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 Y  (: Y/N?)

Thiomersal (antiseptic and antifungal agent.

The pharmaceutical corporation Eli Lilly and Company gave thiomersal the trade name Merthiolate. It has been used as a preservative in vaccines, immunoglobulin preparations, skin test antigens, antivenins, ophthalmic and nasal products, and tattoo inks.[3] Its use as a vaccine preservative was controversial, and it was phased out from routine childhood vaccines in the European Union, and a few other countries in response to popular fears.[4] The current scientific consensus is that no convincing scientific evidence supports these fears.[5][6]

In the U.S., Thiomersal has been removed from or reduced to trace amounts in all vaccines routinely recommended for children 6 years of age and younger with the exception of inactivated influenza vaccine. Vaccines with trace amounts of thiomersal contain 1 microgram or less of mercury per dose, less than 2.5% of the intake of mercury considered tolerable per day by the WHO.[7][8]

Contents

  • Structure 1
  • Use 2
  • Toxicology 3
    • Allergies 3.1
    • Autism 3.2
  • History 4
  • See also 5
  • References 6

Structure

Thiomersal features

  1. ^ a b Melnick, J. G.; Yurkerwich, K.; Buccella, D.; Sattler, W.; Parkin, G. (2008). "Molecular Structures of Thimerosal (Merthiolate) and Other Arylthiolate Mercury Alkyl Compounds".  
  2. ^ http://chem.sis.nlm.nih.gov/chemidplus/rn/54-64-8
  3. ^ Sharpe, M. A.; Livingston, A. D.; Baskin, D. S. (2012). "Thimerosal-Derived Ethylmercury is a Mitochondrial Toxin in Human Astrocytes: Possible Role of Fenton Chemistry in the Oxidation and Breakage of mtDNA". Journal of Toxicology 2012: 1.  
  4. ^ 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.  
  5. ^ Immunization Safety Review Committee, Board on Health Promotion and Disease Prevention, Institute of Medicine (2004). Immunization Safety Review: Vaccines and Autism. Washington, DC: The National Academies Press.  
  6. ^ Doja, Asif; Roberts, Wendy (November 2006). "Immunizations and autism: a review of the literature".  
  7. ^ http://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/VaccineSafety/UCM096228
  8. ^ Bose-O'Reilly; et al. "Mercury Exposure and Children’s Health". Curr Probl Pediatr Adolesc Health Care. Retrieved 4 July 2015. 
  9. ^ a b c d "Thimerosal in vaccines". Center for Biologics Evaluation and Research, U.S. Food and Drug Administration. 2008-06-03. Retrieved 2008-07-25. 
  10. ^ a b c d e f Baker JP (2008). "Mercury, Vaccines, and Autism: One Controversy, Three Histories". Am J Public Health 98 (2): 244–53.  
  11. ^ "Thimerosal in Vaccines: Frequently Asked Questions".  
  12. ^ Coordinating Center for Infectious Diseases (2007-10-26). "Thimerosal in seasonal influenza vaccine". Centers for Disease Control and Prevention. Archived from the original on 2008-04-11. Retrieved 2008-04-02. 
  13. ^ "Mercury in plasma-derived products". U.S. Food and Drug Administration. 2004-09-09. Archived from the original on 2007-09-29. Retrieved 2007-10-01. 
  14. ^ Global Advisory Committee on Vaccine Safety (2006-07-14). "Thiomersal and vaccines". World Health Organization. Retrieved 2007-11-20. 
  15. ^ Hamilton, Jon (17 December 2012). "Doctors Argue Against Proposed Ban on Vaccine Preservative".  
  16. ^ Bryant, Alison (24 January 2013). "U.N. excludes vaccine preservative from mercury treaty". fiercevaccine.com. Retrieved 25 February 2013. 
  17. ^ "Safety data sheet, Thiomersal Ph Eur, BP, USP" (PDF). Merck. 2005-06-12. Retrieved 2010-01-01. 
  18. ^ Clarkson TW (2002). "The three modern faces of mercury". Environ Health Perspect 110 (S1): 11–23.  
  19. ^ a b c Clarkson TW, Magos L (2006). "The toxicology of mercury and its chemical compounds". Crit Rev Toxicol 36 (8): 609–62.  
  20. ^ Clarkson TW, Vyas JB, Ballatori N (2007). "Mechanisms of mercury disposition in the body". Am J Ind Med 50 (10): 757–64.  
  21. ^ Dórea JG (2011). "Integrating experimental (in vitro and in vivo) neurotoxicity studies of low-dose thimerosal relevant to vaccines". Neurochem Res 36 (6): 972–38.  
  22. ^ 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.  
  23. ^ 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.  
  24. ^ Aberer W (1991). "Vaccination despite thimerosal sensitivity". Contact Dermatitis 24 (1): 6–10.  
  25. ^ 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.  
  26. ^ Czarnobilska E, Obtulowicz K, Dyga W, Spiewak R (2011). "The most important contact sensitizers in Polish children and adolescents with atopy and chronic recurrent eczema as detected with the extended European Baseline Series". Pediatr Allergy Immunol 22 (2): 252–6.  
  27. ^ "Thimerosal in vaccines: frequently asked questions (FAQs)". Center for Biologics Evaluation and Research, U.S. Food and Drug Administration. 2007-06-07. Retrieved 2008-07-22. 
  28. ^ DeStefano F (2007). "Vaccines and autism: evidence does not support a causal association". Clin Pharmacol Ther 82 (6): 756–9.  
  29. ^ Doja A, Roberts W (2006). "Immunizations and autism: a review of the literature". Can J Neurol Sci 33 (4): 341–6.  
  30. ^ a b Immunization Safety Review Committee, Board on Health Promotion and Disease Prevention,  
  31. ^ World Health Organization (2006). "Thiomersal and vaccines: questions and answers". Retrieved 2009-05-19. 
  32. ^ Centers for Disease Control (2008-02-08). "Mercury and vaccines (thimerosal)". Retrieved 2009-05-19. 
  33. ^ Sugarman SD (2007). "Cases in vaccine court—legal battles over vaccines and autism". N Engl J Med 357 (13): 1275–7.  
  34. ^ Harris G, O'Connor A (2005-06-25). "On autism's cause, it's parents vs. research". New York Times. Retrieved 2010-07-02. 
  35. ^  
  36. ^ Autism cases in vaccine court:
    • Sugarman SD (2007). "Cases in vaccine court—legal battles over vaccines and autism". N Engl J Med 357 (13): 1275–7.  
    •  
  37. ^ U.S. Patent 1,672,615 "Alkyl mercuric sulphur compound and process of producing it".

References

See also

Morris Kharasch, a chemist at the University of Maryland, filed a patent application for thiomersal in 1927;[37] Eli Lilly later marketed the compound under the trade name Merthiolate.[10] In vitro tests conducted by Lilly investigators H. M. Powell and W. A. Jamieson found that it was forty to fifty times as effective as phenol against Staphylococcus aureus.[10] 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. By 1938, Lilly's assistant director of research listed thiomersal as one of the five most important drugs ever developed by the company.[10]

History

[36] to seek damages from alleged toxicity from vaccines, including those purportedly caused by thiomersal.U.S. federal court Thousands of lawsuits have been filed in a [35].cause of autism and diverting resources away from research into more promising areas for the [34] This controversy has caused harm due to parents attempting to treat their autistic children with unproven and possibly dangerous treatments, discouraging parents from vaccinating their children due to fears about thiomersal toxicity,[33] reject any role for thiomersal in autism or other neurodevelopmental disorders.[32] and the CDC[9]Food and Drug Administration as well as governmental agencies such as the [31] Following a review of mercury-containing food and drugs mandated in 1999, the

Autism

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;[22] a higher prevalence of contact allergy (up to 6.6%) was observed in German populations.[23] Thiomersal-sensitive individuals can receive intramuscular rather than subcutaneous immunization,[24] though there have been no large sample sized studies regarding this matter to date. In real-world practice on vaccination of adult populations, contact allergy does not seem to elicit clinical reaction.[23] Thiomersal allergy has decreased in Denmark, probably because of its exclusion from vaccines there.[25] In a recent study of Polish children and adolescents with chronic/recurrent eczema, positive reactions to thiomersal were found in 11.7% of children (7–8 y.o.) and 37.6% of adolescents (16–17 y.o.). This difference in the sensitization rates can be explained by changing exposure patterns: The adolescents have received six thiomersal-preserved vaccines during their life course, with the last immunization taking place 2–3 years before the mentioned study, younger children received only four thiomersal-preserved vaccines, with the last one applied 5 years before the study, while further immunizations were performed with new thiomersal-free vaccines.[26]

Allergies

[21] Thimerosal at concentrations relevant for infants' exposure (in vaccines) is toxic to cultured human-brain cells and to laboratory animals.[19] Cases have been reported of severe

[9].thiosalicylate) and +Hg5H2 (Cethylmercury In the body, it is metabolized or degraded to [17] Thiomersal is very toxic by inhalation, ingestion, and in contact with skin (EC

Toxicology

[16] Citing medical and scientific consensus that thiomersal in vaccines posed no safety issues, but that eliminating the preservative in multi-dose vaccines, primarily used in developing countries, will lead to high cost and a requirement for refrigeration which the developing countries can ill afford, the UN’s final decision is to exclude thiomersal from the treaty.[15] backed away from an earlier proposal of adding thiomersal in vaccines to the list of banned compounds in a treaty aimed at reducing exposure to mercury worldwide.United Nations Environment Program The [14] In the United States, countries in the European Union and a few other affluent countries, thiomersal is no longer used as a preservative in routine childhood

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 vaccinated with a diphtheria vaccine that lacked a preservative.[9] Unlike other vaccine preservatives used at the time, thiomersal does not reduce the potency of the vaccines that it protects.[10] Bacteriostatics like thiomersal are not needed in single-dose injectables.[11]

Use

[1]

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.