- Nov 23, 2017 -
Praziquantel is white or almost white crystalline powder; it is odorless with a slightly bitter taste. It also has hygroscopic effect. Solubility (g/100m1): 9.7 in ethanol, 56.7 in chloroform, and 0.04 in water. It is easily soluble in dimethyl sulfoxide (DMSO), but insoluble in ether. It has a melting point of 136~141 ℃. Acute toxicity LD50 in mice and rats (mg/kg): 2000~3000 oral administration,> 3,000 subcutaneously injection.
Chemical and Physical Properties
Chemical and Physical Properties
Freely soluble in ethanol or dichloromethane. Slightly soluble in water
white crystalline powder
Praziqurel and Schistosomiasis:
Schistosomiasis is parasitic disease with both human and animal being prone to get infected. Schistosome has a relative complicated life history. Adult parasites live in the mesenteric vein and portal vein blood of people, cattle, pigs and some other mammals, and therefore humans and these animals are called as the adult host or definitive host.
Praziquantel is a kind of common drugs for treatment of schistosomiasis with an extremely small animal toxicity. After its oral administration, it is rapidly absorbed in the digestive tract. The time of the plasma concentration for reaching peaks: 5 minutes for mice, 15~30 minutes for rat, 30 to 120 minutes for dogs, and 2 h for sheep. After its absorption this drug is widely distributed in all tissues and organs; it is even able to penetrate through the blood-brain barrier of rats and can also enter into the bile of dogs. It can induce of influx of the Ca 2+ located outside of the schistosome parasite muscle cell membrane, and thus causing muscle contractures and loss of ability of sucking parasite location. At the same time, it also causes deficiency in sugar metabolism and energy metabolism, disrupting the "With immunization" state and then working together with the host immune system for finally eliminating the parasites. Therefore, it has good killing efficacy in treating China branch schistosomiasis, tapeworm, lung fluke, cysticercosis and also immature parasites (cercariae and miracidia).
The common side effects of praziquantel:
1. During the first 1 hour of medication of the first time: dizziness, headache, nausea, abdominal pain, diarrhea, fatigue, aching limbs can occur, usually at a lesser extent and short duration, and does not affect the treatment without specific treatment.
2. In a few cases, there may be symptoms such as heart palpitations, chest tightness, and T wave change and primary contraction in ECG; supraventricular tachycardia and atrial fibrillation can sometimes also happen.
3. In a few cases there may be a transient increase in transaminases and toxic hepatitis.
4. It sometimes can induce mental disorders and gastrointestinal bleeding.
5. Hernia, allergic reactions (rash, asthma), etc. are also seen.
There are a variety of synthetic routes (isoquinoline route, piperazine route, and phenethylamine route). Isoquinoline has advantages such as wide sources of initial raw material and low cost. Isoquinoline can be converted to 1-benzoyl-2-cyano-1,2-dihydro-isoquinoline through Reissetr reaction. It is further converted to 1-benzoyl-aminomethyl-1, 2, 3, 4-tetrahydroisoquinoline through pressurized hydrogenation. Then followed by cyclization with chloroacetyl chloride to give 2-benzoyl-1,3, 4,6,7,11b-hexahydro-2H-pyrazino[2,1-b]isoquinolin-4-ketone. Finally, apply phosphoric acid hydrolysis and perform condensation reaction with cyclohexanecarboxylic acid chloride to obtain the final product.
There are a variety of synthetic routes for industrial production including isoquinoline route, piperazine route, and phenethylamine route, among which the isoquinoline route is the best. In this route, first perform adduct reaction between isoquinoline and benzoyl chloride as well as potassium cyanide, further go through catalytic hydrogenation and rearrangement to generate 1-benzoyl-methyl-amino-1,2,3,4-tetrahydroisoquinoline, and then sequentially go through chlorine acetylation, cyclization, hydrolysis under increased pressure, and cyclohexanone acylation to generate the final product.
Take phenethylamine as the raw material, after acylation through chloroacetyl chloride, further introduce the amino group after adding terephthalamide potassium for amination reaction, then have cyclization reaction in the action of phosphorus oxychloride to give 3,4-dihydroisoquinoline derivative; further go through hydrogenation and hydrolysis to obtain 1-aminomethyl-tetrahydroquinoline; successively use cyclohexane carboxylic acid chloride and chloroacetyl chloride for acylation and finally go through dehydrochlorination and cyclization to obtain praziquantel.
You can alternatively use isoquinoline as raw material; it first go through Reissert reaction to introduce a cyano group in l position and have nitrogen benzoylated, followed by hydrogenation while benzoyl group is transferred to the amino group of the side chain, further introduce a chlorine acetyl group to the amino group on the ring, then successively go through cyclization, hydrolysis, cyclohexanone formylation to obtain praziquantel.
Praziquantel is a good antiparasite drug for Schistosomiasis. If you want to know more information details, please contact us.
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