Controloc,Byk Gulden ,Germany
An antiulcerative. Gastric pump inhibitor.
ChEBI: Pantoprazole sodium is an organic sodium salt. It has a role as an EC 3.6.3.10 (H(+)/K(+)-exchanging ATPase) inhibitor and an anti-ulcer drug. It contains a pantoprazole(1-).
2-Chloromethyl-4,5-dimethoxy-3-methylpyridinium chloride (about 1.5 g) are added to a solution of 5-difluoromethoxy-1H-benzimidazole-2-thiol in 10 ml of ethanol and 10 ml of 1 N sodium hydroxide solution. The yellow reaction mixture is stirred at 20°C for 1 hour, a further 10 ml of water are added,
whereupon a colorless solid precipitates out, the mixture is stirred for a further 5 hours and filtered and the residue is rinsed with 1 N sodium hydroxide solution and water and dried to constant weight. The 5difluoromethoxy-2-[(4,5-dimethoxy-2-pyridyl)methylthio]-1H-benzimidazole is obtained as an oil.
5-Difluoromethoxy-2-[(4,5-dimethoxy-2-pyridyl)methylthio]-1H-benzimidazole (about 1 g) are dissolved in 10 ml of dioxane and 2 ml of 1 N sodium hydroxide solution. An equimolar amount of a titrated aqueous sodium hypochlorite solution, to which 1 mole per liter of sodium hydroxide solution has been added, is first added dropwise, while cooling with ice. After one hour a further equivalent and after 3 hours half the equimolar amount of sodium hypochlorite are added, to achieve complete reaction. After a reaction time of 4 hours, 5 ml of 5% strength sodium thiosulfate solution and another 25 ml of dioxane are added and the upper dioxane phase is separated off, washed once with 5 ml of sodium thiosulfate solution and concentrated on a rotary evaporator. The oily residue is dissolved in 20 ml of water and 10 ml of ethyl acetate and the solution is brought to pH 7 with about 100 ml of a buffer solution of pH 6.8. The solid which has precipitated out is filtered off with suction over a suction filter, washed with water, extracted by stirring at 0C with acetone and dried. 5-Difluoromethoxy-2-[(4,5-dimethoxy-2pyridyl)methanesulfinyl]-1H-benzimidazole is prepared; yield about 85%.
Pantoprazole sodium, racemicsodium5-(difluoromethoxy)-2-[[3,4-dimethoxy-2-pyridinyl)methyl]sulfinyl]-1H-benzimidazole sesquihydrate is a white tooff-white crystalline powder that is freely soluble in water,very slightly soluble in phosphate buffer at pH 7.4, and practicallyinsoluble in n-hexane. The benzimidazole of this drughas a weakly basic nitrogen (pyridine N, pKa 3.83) and an benzimidazoleproton (pKa 0.11), facilitating formulation as asodium salt. The stability of the compound in aqueous solutionis pH dependent; the rate of degradation increases with decreasingpH. At ambient temperature, the degradation half-lifeis approximately 2.8 hours at pH 5.0 and approximately 220hours at pH 7.8.
The absorption of pantoprazole is rapid (Cmax of2.5μg/mL, Tmax 2.5 hours) after single or multiple oral40-mg doses. Pantoprazole is well absorbed (77% bioavailability).Administration with food may delay its absorptionbut does not alter pantoprazole bioavailability. Pantoprazoleis distributed mainly in extracellular fluid. The serum proteinbinding of pantoprazole is about 98%, primarily to albumin.Pantoprazole is extensively metabolized in the liver throughthe CYP system, including O-demethylation (CYP2C19),with subsequent sulfation. Other metabolic pathways includesulfur oxidation by CYP3A4. There is no evidencethat any of the pantoprazole metabolites have significantpharmacological activity. Approximately 71% of a dose of pantoprazole is excreted in the urine, with 18% excretedin the feces through biliary excretion.
