General
Preferred name
THIMEROSAL
Synonyms
Merzonin ()
Thiomersalate ()
Sodium ethylmercurithiosalicylate ()
Merthiolate ()
Ethylmercury sodium salt ()
Mertorgan ()
Thimerosal ()
Merfamin ()
Mercurothiolate ()
P&D ID
PD001732
CAS
54-64-8
11004-81-2
Tags
drug
contains metal
Drug Status
approved
Structure
Probe scores
P&D probe-likeness score
[[ v.score ]]%
Structure formats
[[ format ]]
[[ compound[format === 'MOL' ? 'molblock' : format.toLowerCase()] ]]
Description
(extracted from source data)
TOXICITY Ld50 Oral: 75 mg/kg (mouse), 91 mg/kg (mouse) [L1694]; ; Although methylmercury (meHg) is considered a hazardous substance that is to be avoided even at small levels when consumed in foods such as seafood and rice (in Asia), the World Health Organization considers small doses of thimerosal safe regardless of multiple/repetitive exposures to vaccines that are predominantly taken during pregnancy or infancy [L1685, L1686, L1689].; ;
HALF-LIFE A study was done to study the pharmacokinetics of Thimerosal in mice. Estimated half-lives (in days) were 8.8 for blood, 10.7 for brain, 7.8 for heart, 7.7 for liver and 45.2 for kidney [L1685].; ; The the long half-life of ethylmercury (~50 days on average in humans) results in accumulation that may be harmful to the developing fetal brain, as it is more susceptible to organomercurial compounds than the adult brain [L1687].;
PHARMACODYNAMICS Thimerosal is an organomercurial compound and derivative of thiosalicyclic acid with antibacterial and antifungal properties [L1672]. Thimerosal, which consists of approximately 50% mercury by weight, has been one of the most widely used preservatives in vaccines. It is metabolized/degraded to ethylmercury and thiosalicylate. Ethylmercury is an organomercurial that must be carefully distinguished from methylmercury, a closely related substance that has been the focus of many studies. Methylmercury is the type of mercury found in various species of fish [L1688]. Experimental data demonstrates that the toxicokinetics of thimerosal (ethylmercury) is vastly different from that of methyl-mercury. Thus, methyl-mercury is not a suitable reference for assessing the risk from exposure to thimerosal-derived mercury [L1692].; ; Prior to the recent initiative to reduce or eliminate thimerosal from childhood vaccines, the maximum cumulative exposure to mercury via routine childhood vaccinations during the first 6 months of life was 187.5 micrograms. In the most recently formulated vaccines, the maximum cumulative exposure during the first 6 months of life should now be less than 3 micrograms of mercury. Currently, thimerosal may still be used in the early stages of manufacturing of certain childhood vaccines, however, only a trace remains after a chemical purification process. Note that the dose above is indicated for children 1-6 months of age is applicable only in the United States, and other countries may have varying indications [L1687].
MOA Although its mechanism of action is not fully understood, thimerosal inhibits sulfhydryl-containing active site of various enzymes and binds to sulfhydryl compounds, including glutathione, cysteine, and sulfhydryl groups of proteins. In addition, thimerosal activates the InsP3 calcium channel on the endoplasmic reticular membrane, thereby triggering the release of intracellular calcium resulting in a calcium-induced calcium-influx of extracellular calcium. Therefore, thimerosal may induce or inhibit various cellular functions that are dependent on the signaling of calcium [L1674].; ; Ethylmercury is metabolized to inorganic mercury more rapidly than methylmercury. This difference in metabolism may account for kidney pathology that can result from toxic quantities. Also, whereas the increase in oxidative stress and induction of apoptosis observed in vitro with large doses (405 μg/L to 101 mg/L) of thimerosal may explain its damaging neurological effects. The effects of low-dose ethylmercury are not completely understood to date. It is known, however, that the shorter half-life of ethylmercury (the metabolite of thimerosal) allows for very limited opportunities of ethylmercury derived from thimerosal in vaccines [L1674].; ; Ethylmercury is a lipophilic cation that is capable of crossing the blood-brain barrier. The octanol/water partition coefficients of methyl and ethylmercury are 1.4 to 1.8, at intracellular pH and [Cl−], therefore, both organomercury compounds will primarily exist as intracellular lipophilic cations. It has been demonstrated that lipophilic cations accumulate inside mitochondria, in a Nernstian fashion, driven by the steady state membrane potential. As the typical mitochondrial membrane potential of astrocytes and neurons is between 140–170 mV, one would expect the concentration of these organomercury compounds within mitochondria to be approximately 1000 times greater than the cytosolic concentration [L1689].; ; ; ; ; ;
Compound Sets
3
DrugBank
DB11590
DrugBank Approved Drugs
DB11590
The Spectrum Collection
External IDs
28
Properties
(calculated by RDKit )
Molecular Weight
405.99
Hydrogen Bond Acceptors
3
Hydrogen Bond Donors
0
Rotatable Bonds
4
Ring Count
1
Aromatic Ring Count
1
cLogP
-1.42
TPSA
40.13
Fraction CSP3
0.22
Chiral centers
0.0
Largest ring
6.0
QED
0.58
Structural alerts
0
No structural alerts detected
Custom attributes
(extracted from source data)
Source data