Recrystallization method for improving the purity of finasteride
A finasteride and recrystallization technology, which is applied in the field of recrystallization to improve the purity of finasteride, can solve problems such as relatively difficult removal, and achieve the effects of increasing product competitiveness, high yield, and mild reaction conditions
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Embodiment 1
[0018] The specific operation of the recrystallization method for improving the purity of finasteride provided in this example is as follows.
[0019] (1) To prepare the crude product solution, take the crude product of finasteride prepared by the prior art (provided by Tianfang Pharmaceutical Co., Ltd., 0.4% single impurity, 0.9% total impurity, impurity І (N-tert-butyl-3-oxo- 4-aza5α-androstane-17β-amide) 0.4%), weighed 50g, placed in a 500mL three-neck flask, added 250mL of water-soluble solvent methanol 5 times the crude product of finasteride, and kept at room temperature ( 25°C) and stir until fully dissolved, add 1.5g of activated carbon (3% by weight of the crude product of finasteride), heat to about 55°C and continue stirring for 10 minutes, filter while hot, rinse with a small amount of methanol, combine the filtrates, and set aside.
[0020] (2) Prepare a crystallization solution, the crystallization solution is phosphoric acid-disodium hydrogen phosphate buffer so...
Embodiment 2
[0025] The specific operation process of the recrystallization method for improving the purity of finasteride provided in this example is the same as in Example 1, and only some parameters are adjusted as follows:
[0026] In step (1), ethanol is used as the water-soluble solvent.
[0027] After testing according to the existing pharmacopoeia testing method, the obtained white crystalline powder of finasteride had a yield of 94.2% and a purity of 99.63%, of which the total impurity was 0.37%, the largest single impurity was 0.10%, and the impurity І was 0.06%.
Embodiment 3
[0029] The specific operation process of the recrystallization method for improving the purity of finasteride provided in this example is the same as in Example 1, and only some parameters are adjusted as follows:
[0030] In step (1), acetone is used as the water-soluble solvent.
[0031] After testing according to the existing pharmacopoeia detection method, the obtained white crystalline powder of finasteride had a yield of 92.9% and a purity of 99.47%, of which the total impurity was 0.53%, the largest single impurity was 0.15%, and the impurity І was 0.09%.
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