Method for purifying piroxicam

A purification method and technology of piroxicam, applied in the field of chemical medicine, can solve the problems of high solvent toxicity, large solvent consumption and high purification cost, and achieve the effects of high-purity purification and high recovery rate

Inactive Publication Date: 2019-02-22
CHONGQING SANSHENG IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the commonly used purification method of piroxicam is to use ethanol, methanol, isopropanol, xylene, ethyl acetate, isopropyl acetate, acetone, acetonitrile, tetrahydrofuran, etc. as solvents, and purify by recrystallization. When these solvents are used for recrystallization, the solvent consumption is relatively large, the purification cost is relatively high, and some solvents are highly toxic, which is not conducive to industrialized large-scale purification of piroxicam

Method used

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  • Method for purifying piroxicam

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Effect test

Embodiment 1

[0034] Get 10g of piroxicam crude product, HPLC purity 98.954%, main impurity 0.698%, join in the mixed solution of 50g dioxane and 50g xylene, heat up and reflux, until dissolving completely (solution becomes clear). Remove the insoluble matter by suction filtration while it is hot, and cool the filtrate to room temperature, a large amount of solids can be seen to precipitate, and then suction filtration, the obtained filter cake is dried under reduced pressure at 80°C to obtain the pure product of piroxicam. The yield is 77%, the HPLC purity is 99.456%, the main impurity is 0.442%, and the calculated impurity removal rate is 36.7%.

Embodiment 2

[0036] Get 10g of piroxicam crude product, HPLC purity 98.954%, main impurity 0.698%, join in the mixed solution of 50g dioxane and 100g xylene, heat up and reflux, until dissolving completely (solution becomes clear). Remove the insoluble matter by suction filtration while it is hot, and cool the filtrate to room temperature, a large amount of solids can be seen to precipitate, and then suction filtration, the obtained filter cake is dried under reduced pressure at 80°C to obtain the pure product of piroxicam. The yield is 78.6%, the HPLC purity is 99.517%, the main impurity is 0.442%, and the calculated impurity removal rate is 44.7%.

Embodiment 3

[0038] Get 5g of piroxicam crude product, HPLC purity 99.456%, main impurity 0.442%, join in the mixed solution of 6.67g dioxane and 13.3g xylene, heat up and reflux to dissolve completely (solution becomes clear). Remove the insoluble matter by suction filtration while it is hot, and cool the filtrate to room temperature, a large amount of solids can be seen to precipitate, and then suction filtration, the obtained filter cake is dried under reduced pressure at 80°C to obtain the pure product of piroxicam. The yield is 92%, the HPLC purity is 99.730%, the main impurity is 0.242%, and the calculated impurity removal rate is 45.2%.

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Abstract

The invention relates to a method for purifying piroxicam. The method comprises the following steps that (1) xylene and dioxane are mixed at the volume ratio of (1 to 5):1 to obtain a mixed solvent; (2) crude piroxicam is added to the mixed solvent and heated until completely dissolved; (3) the mixture is filtered at a high temperature, and filtrate is cooled to precipitate out a solid; and (4) filtering is carried out, and a filter cake is dried to obtain pure piroxicam. According to the method, piroxicam is recrystallized through the solvent prepared by mixing xylene and dioxane, the solubility of piroxicam is good, the solvent to solute ratio is decreased, the purification cost of piroxicam is lowered, the recovery rate of piroxicam is high, the purity of piroxicam is higher, and the purification quality of piroxicam is effectively improved.

Description

technical field [0001] The invention relates to the field of chemical medicine, in particular to a purification method of piroxicam. Background technique [0002] The chemical name of piroxicam is 4-hydroxy-2-methyl-1N-2-pyridyl-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide, which is a non-steroidal Anti-inflammatory analgesic. In June 1982, Taiwan Sugar Pfizer went public under the trade name of Feldene, and Toyama Chemical Industry Co., Ltd. went public under the trade name of Baxo. [0003] [0004] Piroxicam is produced in large quantities in my country. In 2016, Guangxi Food and Drug Inspection Institute conducted research on the quality of piroxicam tablets produced at home and abroad, and the results were published in the Journal of Drug Analysis. In this study, a total of 14 impurities were detected in 138 batches of domestic piroxicam tablets, of which impurities 8, 10, 12, and 14 were the main impurities, and the largest impurity in 96% of the samples was im...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D417/12
CPCC07D417/12
Inventor 雷鸣代广会张启航黄越伟谢青山向洪
Owner CHONGQING SANSHENG IND CO LTD
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