Metabolism / Metabolites
Trimethadione has known human metabolites that include Dimethadione.

Toxicity Summary
Dione anticonvulsants reduce T-type calcium currents in thalamic neurons, including thalamic relay neurons. It does so via the inhibition of voltage dependent T-type calcium channels. This raises the threshold for repetitive activity in the thalamus, and inhibits corticothalamic transmission. Thus, the abnormal thalamocortical rhythmicity, which is thought to underlie the 3-Hz spike-and-wave discharge seen on electroencephalogram(EEG) with absence seizures, is dampened.

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Protein Binding
90%

[1]. Synthesis and anticonvulsant activity of bioisosteres of trimethadione, N-derivative-1,2,3-oxathiazolidine-4-one-2,2-dioxides from α-hydroxyamides. Bioorg Med Chem. 2013 Feb 15;21(4):841-6.

[2]. The antihyperalgesic effects of the T-type calcium channel blockers ethosuximide, trimethadione, and mibefradil. Eur J Pharmacol. 2005 Oct 3;521(1-3):79-85.

Trimethadione can cause developmental toxicity according to state or federal government labeling requirements.
Trimethadione is an oxazolidinone that is 1,3-oxazolidine-2,4-dione substituted by methyl groups at positions 3, 5 and 5. It is an antiepileptic agent. It has a role as a geroprotector and an anticonvulsant.
An anticonvulsant effective in absence seizures, but generally reserved for refractory cases because of its toxicity. (From AMA Drug Evaluations Annual, 1994, p378)
Trimethadione is an Anti-epileptic Agent. The physiologic effect of trimethadione is by means of Decreased Central Nervous System Disorganized Electrical Activity.
Trimethadione is a dione-type anticonvulsant with antiepileptic activity. Trimethadione reduces T-type calcium currents in thalamic neurons, thereby stabilizing neuronal membranes, raising the threshold for repetitive activities in the thalamus and inhibiting corticothalamic transmission. This decreases the abnormal thalamocortical rhythmicity, which is thought to underlie the paroxysmal three-cycle-per-second spike-and-wave pattern seen with absence (petit mal) seizures.
Trimethadione is only found in individuals that have used or taken this drug. It is an anticonvulsant effective in absence seizures, but generally reserved for refractory cases because of its toxicity. (From AMA Drug Evaluations Annual, 1994, p378) Trimethadione reduces T-type calcium currents in thalamic neurons, including thalamic relay neurons. It does so via the inhibition of voltage dependent T-type calcium channels. This raises the threshold for repetitive activity in the thalamus, and inhibits corticothalamic transmission. Thus, the abnormal thalamocortical rhythmicity, which is thought to underlie the 3-Hz spike-and-wave discharge seen on electroencephalogram(EEG) with absence seizures, is dampened.
An anticonvulsant effective in absence seizures, but generally reserved for refractory cases because of its toxicity. (From AMA Drug Evaluations Annual, 1994, p378)

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Drug Indication
Used in the control of absence (petit mal) seizures that are refractory to treatment with other medications.

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Mechanism of Action
Dione anticonvulsants reduce T-type calcium currents in thalamic neurons, including thalamic relay neurons. It does so via the inhibition of voltage dependent T-type calcium channels. This raises the threshold for repetitive activity in the thalamus, and inhibits corticothalamic transmission. Thus, the abnormal thalamocortical rhythmicity, which is thought to underlie the 3-Hz spike-and-wave discharge seen on electroencephalogram(EEG) with absence seizures, is dampened.

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Pharmacodynamics
Paramethadione and trimethadione are anticonvulsants indicated in the control of absence (petit mal) seizures that are refractory to treatment with other medications. Dione anticonvulsants are used in the treatment of epilepsy. They act on the central nervous system (CNS) to reduce the number of seizures.

C6H9NO3

143.142

143.058

127-48-0

5576

White to off-white solid powder

1.171g/cm3

78-80°C 5mm

45-46°C

78-80°C/5mm

2.98mmHg at 25°C

1.457

0.311

0

3

0

10

197

0

IRYJRGCIQBGHIV-UHFFFAOYSA-N

InChI=1S/C6H9NO3/c1-6(2)4(8)7(3)5(9)10-6/h1-3H3

3,5,5-trimethyl-1,3-oxazolidine-2,4-dione

Trimetin; Trimethadione; Tridione

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ≥ 40 mg/mL (~279.45 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (17.47 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (17.47 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (17.47 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)