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Pyrimethamine

Pyrimethamine Structure
CAS No.
58-14-0
Chemical Name:
Pyrimethamine
Synonyms
Daraprim;Fansidar;Chloridine;PYRIMETHAMIN;Pirimetamina;Pyremethamine;wr2978;bw50-63;RP 4753;WR 2978
CBNumber:
CB8461315
Molecular Formula:
C12H13ClN4
Molecular Weight:
248.71
MOL File:
58-14-0.mol
MSDS File:
SDS
Modify Date:
2024/9/20 10:46:38

Pyrimethamine Properties

Melting point 233-234°C
Boiling point 393.35°C (rough estimate)
Density 1.2171 (rough estimate)
refractive index 1.6110 (estimate)
storage temp. Keep in dark place,Inert atmosphere,Room temperature
solubility Prepare the solution immediately before use. Dissolve 0.25 g in a mixture of 1 volume of methanol R and 3 volumes of methylene chloride R and dilute to 10 mL with the same mixture of solvents. The solution is clear (2.2.1) and not more intensely coloured than reference solution BY6 (2.2.2, Method II).
pka pKa 7(t=20.0) (Uncertain)
form Solid
color White to Off-White
Water Solubility <0.01 g/100 mL at 21 ºC
λmax 276nm(lit.)
Merck 14,7985
BRN 219864
BCS Class 2 (CLogP), 4 (LogP),3
Stability Stable, but light sensitive. Combustible. Incompatible with strong oxidizing agents.
CAS DataBase Reference 58-14-0(CAS DataBase Reference)
IARC 3 (Vol. 13, Sup 7) 1987
NIST Chemistry Reference Pyrimethamine(58-14-0)
EPA Substance Registry System Pyrimethamine (58-14-0)

SAFETY

Risk and Safety Statements

Symbol(GHS) 
GHS07
Signal word  Warning
Hazard statements  H302
Precautionary statements  P264-P270-P301+P312-P501
Hazard Codes  Xn
Risk Statements  22-36
Safety Statements  26
RIDADR  3249
WGK Germany  3
RTECS  UV8140000
HazardClass  6.1(b)
PackingGroup  III
HS Code  29335990
Toxicity LD50 oral in rat: 440mg/kg
NFPA 704
0
2 0

Pyrimethamine price More Price(3)

Manufacturer Product number Product description CAS number Packaging Price Updated Buy
Sigma-Aldrich(India) 46706 Pyrimethamine VETRANAL?, analytical standard 58-14-0 250MG ₹5477.45 2022-06-14 Buy
TCI Chemicals (India) P2037 Pyrimethamine 58-14-0 1G ₹4400 2022-05-26 Buy
TCI Chemicals (India) P2037 Pyrimethamine 58-14-0 5G ₹12000 2022-05-26 Buy
Product number Packaging Price Buy
46706 250MG ₹5477.45 Buy
P2037 1G ₹4400 Buy
P2037 5G ₹12000 Buy

Pyrimethamine Chemical Properties,Uses,Production

Chemical Properties

White Solid

Uses

For the treatment of toxoplasmosis and acute malaria; For the prevention of malaria in areas non-resistant to pyrimethamine.
Pyrimethamine is a dihydrofolate reductase inhibitor, like the biguanides, and is structurally related to trimethoprim. It is seldom used alone. Pyrimethamine in fixed combinations with dapsone or sulfadoxine is used for treatment and prophylaxis of chloroquine-resistant falciparum malaria. The synergistic activities of pyrimethamine and sulfonamides are similar to those of trimethoprim/sulfonamide combinations. Resistant strains of Plasmodium falciparum have appeared world wide. Prophylaxis against falciparum malaria with pyrimethamine alone is therefore not recommended. Most strains of Plasmodium vivax have remained sensitive. Pyrimethamine is also used in combination with a sulfonamide for the treatment of Toxoplasmosis. It is slowly absorbed from the gastrointestinal tract with peak plasma levels 4–6 hours after dosing. Pyrimethamine is bound to plasma proteins and is extensively metabolized before excretion. Its elimination half-life is 3–5 days.

Indications

Pyrimethamine (Daraprim) is the best of a number of 2,4- diaminopyrimidines that were synthesized as potential antimalarial and antibacterial compounds. Trimethoprim (Proloprim) is a closely related compound.
Pyrimethamine is well absorbed after oral administration, with peak plasma levels occurring within 3 to 7 hours. An initial loading dose to saturate nonspecific binding sites is not required, as it is with chloroquine. However, the drug binds to tissues, and therefore, its rate of renal excretion is slow. Pyrimethamine has a half-life of about 4 days. Although the drug does undergo some metabolic alterations, the metabolites formed have not been totally identified.

Definition

ChEBI: An aminopyrimidine that is pyrimidine-2,4-diamine which is substituted at position 5 by a p-chlorophenyl group and at position 6 by an ethyl group. It is a folic acid antagonist used as an antimalarial or with a sulfonamide to treat toxoplasmo is.

General Description

Odorless white crystalline powder. Tasteless. An antimalarial drug.

Air & Water Reactions

Pyrimethamine is a diaminopyrimidine which is structurally related to trimethoprim. It is effective against erythrocytic stage of Plasmodium (P) falciparum and less so against P. vivax, P. ovale and P. malariae. Pyrimethamine also inhibits the sporogony in the mosquito, resulting in a decrease of transmission of the infection within the community[1].
The mechanism of action of pyrimethamine is related to its inhibition of dihydrofolic reductase necessary for the folic acid synthesis in the parasite. Pyrimethamine acts slowly and is not recommended as monotherapy for acute malaria attacks. Resistance to pyrimethamine developed soon when the drug was used on a large scale as monoprophylaxis [1]. In resistant strains, the enzyme dihydrofolic reductase binds to pyrimethamine several hundred times less than in sensitive strains [2]. This high grade resistance is probably a onestep mutation and cannot be overcome by increasing the dose. However, when combined with long-acting sulphonomides (sulphadoxine), the effect of pyrimethamine is potentiated and the risk of developing resistant strains is far less.

Reactivity Profile

Pyrimethamine together with sulphadoxine (Fansidar) is used in the treatment of P. falciparum malaria (cf. Sulphadoxine: Indications). Pyrimethamine is also valuable in the treatment of toxoplasmosis.

Fire Hazard

Pyrimethamine in combination with sulphadoxine (Fansidar) can cause severe cutaneous adverse reactions (cf. Sulphadoxine: Side effects). Agranulocytosis occurs quite frequently (1/2000) and fatalities have been reported when pyrimethamine is combined with dapsone [3]. When given alone, life-threatening adverse reactions are very rare and the drug is generally well tolerated. Megaloblastic anaemia may, however, occur during long-term treatment with high doses (i.e. for toxoplasmosis) and can be prevented by folinic acid supplementation [4].

Biological Activity

During long-term treatment with high doses, folinic acid supplement is usually given.

Mechanism of action

The combination of pyrimethamine with a long-acting sulfonamide, sulfadoxine, which blocks dihydrofolate synthesis by blocking incorporation of PABA into the dihydrofolate, is called Fansidar, which produces sequential blockage of tetrahydrofolate synthesis similar to that reported for treatment of bacterial infections. Plasmodium enzymes catalyzing folic acid synthesis differ from those enzymes found in other organisms. A single bifunctional protein present in Plasmodium sp. catalyzes the phosphorylation of 6-hydroxymethyl-7,8-hydropterin (a pyrophosphokinase) and the incorporation of PABA into dihydropteroic acid. A second bifunctional enzyme catalyzes the reduction of dihydropteroic acid and thymidylic acid synthesis. As a result, the drug combination (Fansidar) appears to have improved drug-mediated disruption of folic acid in Plasmodium sp.. This combination has been used with quinine for the treatment and prevention of chloroquine-resistant malaria (Plasmodium falciparum, Plasmodium ovale, Plasmodium vivax, and Plasmodium malaria). The combination therapy (Fansidar) has the added advantage of being inexpensive, which is essential for successful therapy in developing countries. When used on its own, pyrimethamine is a blood schizonticide without effects on the tissue stage of the disease.

Clinical Use

Pyrimethamine has been recommended for prophylactic use against all susceptible strains of plasmodia; however, it should not be used as the sole therapeutic agent for treating acute malarial attacks. As mentioned previously, sulfonamides should always be coadministered with pyrimethamine (or trimethoprim), since the combined antimalarial activity of the two drugs is significantly greater than when either drug is used alone. Also, resistance develops more slowly when they are used in combination. Sulfonamides exert little or no effect on the blood stages of P. vivax, and resistance to the dihydrofolate reductase inhibitors is widespread.
In addition to its antimalarial effects, pyrimethamine is indicated (in combination with a sulfonamide) for the treatment of toxoplasmosis.The dosage required is 10 to 20 times higher than that employed in malarial infections.

Side effects

Relatively few side effects are associated with the usual antimalarial dosages. However, signs of toxicity are evident at higher dosages, particularly those used in the management of toxoplasmosis. Many of these reactions reflect the interference of pyrimethamine with host folic acid metabolism, especially that occurring in rapidly dividing cells. Toxic symptoms include anorexia, vomiting, anemia, leukopenia, thrombocytopenia, and atrophic glossitis. CNS stimulation, including convulsions, may follow an acute overdose.The side effects associated with the pyrimethamine–sulfadoxine combination include those associated with the sulfonamide and pyrimethamine alone. In addition, there is evidence of a greater incidence of allergic reactions, particularly toxic epidermal necrolysis and Stevens-Johnson syndrome, with the combination. This carries an estimated mortality of 1:11,000 to 1:25,000 when used as a chemoprophylactic.

Safety Profile

Poison by ingestion, subcutaneous, and intraperitoneal routes. Experimental teratogenic and reproductive effects. Questionable carcinogen. Human mutation data reported. When heated to decomposition it emits very toxic fumes of Cland NOx. Used as an antimalarial drug for humans and to treat toxoplasmosis in hogs.

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Pyrimethamine Spectrum

2,4-Diamino-5-(4-chlorophenyl)-6-ethylpyrimidine [2-amino-5-(4-chlorophenyl)-6-ethyl-pyrimidin-4-yl]amine Pyrimethamine,5-(4-Chlorophenyl)-6-ethyl-2,4-pyrimidinediamine Pyrimethamine (200 mg) PyriMethaMine,darapriM 5-(p-chlorophenyl)-6-ethyl-4-pyrimidinediamine BW 50-63 bw50-63 Chloridin Chloridyn Darachlor Daraclor Darapram 5-(4’-chlorophenyl)-2,4-diamino-6-ethylpyrimidine 5-(4'-Chlorophenyl)-2,4-diamino-6-ethylpyrimidine 5-(4-Chlorophenyl)-2,4-diamino-6-ethylpyrimidine 5-(4-chlorophenyl)-6-ethylpyrimidine-2,4-diyldiamine 5-(P-Chlorophenyl)-6-ethyl-2,4-diaminopyrimidine Pyrimidine,2,4-diamino-5-(p-chlorophenyl)-6-ethyl- RP 4753 Tindurin Tinduring WR 2978 wr2978 PYRIMETHAMINE Daraprime Diaminopyritamin Erbaprelina Khloridin Malacid Malocid Malocide Maloprim NCI-C01683 nsc3061 NSC-3061 Pirimecidan Pirimetamin Primethamine pyrimethamine(INN) Pyrimidine, 2,4-diamino-5-(p-chlorophenyl)-6-ethyl- PYRIMETHAMINE BP 5-(4-CHLOROPHENYL)-6-ETHYL-2,4-PYRIMIDINEDIAMINE 5-(4-CHLOROPHENYL)-6-ETHYL-PYRIMIDINE-2,4-DIAMINE 2,4-diamino-5-(p-chlorophenyl)-6-ethylpyrimidine PYRIMETHAMINE HCL Pyrimeigamine Pyrimethamine BP98 USP23 PYRIMETHAMINE VETRANAL, 250 MG 5(4-Chloro Phenyl)-6-Ethyl-2,4-pyridine diamine PYRIMETHAMINE,USP PYRIMETHAMINEUM Pyrimethamine (base and/or unspecified salts) Pirimetmin 2,4-Diamino-5-chlorophenyl-6-ethylpyrimidine 2,4-Pyrimidinediamine, 5-(4-chlorophenyl)-6-ethyl- 2,4-Pyrimidinediamine, 5-(p-chlorophenyl)-6-ethyl- 2,4-Pyrimidinediamine,5-(4-chlorophenyl)-6-ethyl-