A kind of preparation method of probenecid ethyl

Abstract

The present invention relates to a method for preparing probenecid ethyl, characterized in that the specific steps are as follows: take a four-mouth reaction bottle and add probenecid, then add anhydrous ethanol, start stirring, slowly heat up until probenecid is completely dissolved, add 4a molecular sieves to the four-mouth bottle, continue to heat up to reflux, and the reaction solution gradually becomes turbid; reflux decolorization for 20-30mins, cool down after decolorization is completed; filter the reaction solution, start the freeze-drying procedure; the freeze-dried powder is a white or off-white crystalline powder, and probenecid ethyl is prepared. Its purity can reach more than 99.0% (by HPLC); the content of the impurity is further detected by H-NMR to be 98.2%, which can be used as an impurity reference.

Description

Technical Field

[0001] The invention relates to a method for preparing ethyl probenecid, in particular to a method for preparing ethyl 4-(dipropylaminosulfonyl)benzoate, an impurity of probenecid (sodium), which is used for the detection and quality control of raw materials and preparations of sodium probenecid. Background Art

[0002] Probenecid is a white crystalline powder. Melting point 198-201℃. It is soluble in acetone, slightly soluble in ethanol or chloroform, and almost insoluble in water. It is soluble in dilute sodium hydroxide solution and almost insoluble in dilute acid. It is odorless and tastes slightly bitter. It is an anti-gout drug and an adjuvant drug for antibiotic treatment. Probenecid sodium is its sodium salt, a white crystalline powder, odorless, slightly bitter, very soluble in water, easily soluble in methanol and ethanol, soluble in anhydrous ethanol, and almost insoluble in acetone and ethyl acetate. The pH value is 6.5-8 (determined by ChP2020 General Principle 0631).

[0003] In addition to its role in treating chronic gout, probenecid can also significantly optimize the pharmacokinetic properties of various β-lactam antibiotics. Currently, a compound preparation consisting of probenecid and ampicillin has been used clinically. [1] , which can not only significantly reduce the dosage of corresponding antibiotics, thereby reducing the incidence of adverse reactions to antibiotics, but also increase the compliance of antibiotic treatment and reduce the selection of drug-resistant bacteria. The development of the combined use of probenecid (sodium) and various β-lactam antibiotics has extremely important clinical value and also has a very positive social significance for reducing the use of antibiotics and alleviating bacterial resistance.

[0004] Controlling the level of impurities and improving the purity of active ingredients are of great significance to improving the quality and safety of drugs. At present, the research on probenecid (sodium) impurities is not in-depth, and there are few literature reports. There are also very few probenecid (sodium) impurities included in the pharmacopoeias of various countries, and only the European Pharmacopoeia has controls on specific impurities. The impurity control limits of other pharmacopoeias are very loose, as shown in the following table:

[0005]

[0006] Experimental results show that during the preparation of probenecid (sodium) (Figure 1), especially during the refining process of probenecid, probenecid will react with the refining solvent - ethanol to produce a specific impurity 4-(dipropylaminosulfonyl)benzoic acid ethyl ester (hereinafter referred to as: probenecid ethyl ester) (Figure 2), which is the European Pharmacopoeia specific impurity D.

[0007] According to current literature [2]It was reported that Bai Jincai et al. prepared four genotoxic impurities of probenecid. Although there are sporadic reports on probenecid ethyl ester, there are no clear literature or patents on the preparation process. Summary of the invention

[0008] The purpose of the present invention is to provide a method for preparing probenecid ethyl, that is, a method for preparing ethyl 4-(dipropylaminosulfonyl)benzoate, an impurity of probenecid (sodium). The prepared probenecid ethyl can be used as a standard or reference substance for the impurity and for the detection and quality control of raw materials and preparations of probenecid sodium, and has a very important application in improving the effectiveness, safety and quality controllability of probenecid sodium series products.

[0009] The technical solution of the present invention is a method for preparing probenecid ethyl achieved in this way, characterized in that the specific steps are as follows:

[0010] 1. Take a four-necked reaction bottle, add an appropriate amount of probenecid, add 5-10 times the volume ratio of anhydrous ethanol, and connect the four-necked bottle to a tetrafluoro anchor stirrer, a condenser, a thermometer, and a heating jacket;

[0011] 2. Start stirring, add 2-10% of the volume of concentrated sulfuric acid in anhydrous ethanol with a disposable dropper, turn on the heating jacket, slowly heat up until the probenecid is completely dissolved, the reaction solution is clear, and add a certain amount of 4a molecular sieves to the four-necked bottle, the amount is 0.3-0.5 times the amount of probenecid;

[0012] 3. Continue to raise the temperature to reflux, reflux reaction for 5-10 hours, the reaction solution gradually becomes turbid;

[0013] 4. After the reflux esterification reaction is completed, wet an appropriate amount of activated carbon (3-5% of the amount of probenecid) with anhydrous ethanol, add it to the reaction bottle, reflux decolorize for 20-30 minutes, and cool down after decolorization is completed;

[0014] 5. Filter the reaction solution, remove the activated carbon and 4a molecular sieve, and collect the filtrate; transfer the filtrate to a group of 15 ml vials, put the vials into the freeze dryer, close the freeze dryer door, and start the freeze drying process;

[0015] 6. Pre-freeze to -30-45℃, keep warm for 2-4 hours, start sublimation, open vacuum and heat to 0-5℃, keep warm for 3-5 hours; then increase the sublimation temperature to 5-10℃ and keep warm for 2-4 hours; continue to increase the sublimation temperature to 15-20℃ and keep warm for 1-3 hours; then continue to increase the sublimation temperature to 20-25℃ and keep warm for 1-4 hours. Finally, perform analytical drying and heat to 30℃, keep warm for 2-4 hours and end freeze-drying;

[0016] 7. The lyophilized powder is a white or off-white crystalline powder, which is used to prepare probenecid ethyl.

[0017] The positive effect of the present invention is to prepare high-purity probenecid ethyl with the following characteristics:

[0018] 1. Add sulfuric acid to catalyze the esterification reaction. The catalytic amount is 3-5% of the anhydrous ethanol solvent. Too little sulfuric acid will not have sufficient catalytic and dehydration capabilities. Too much sulfuric acid will produce side reactions with ethanol.

[0019] 2. Add molecular sieve to remove the produced water in the reaction and promote the esterification reaction to proceed thoroughly. The amount used is 30-50% of the reactant probenecid to completely remove water;

[0020] 3. Control the reaction time to 5-7 hours. If the reaction time is too short, the esterification will not be complete. If the reaction time is too long, side reactions may occur easily.

[0021] 4. The freeze-drying process is used to remove the solvent, the solvent is removed cleanly, and the solvent can be evaporated at high temperature to avoid the decomposition of probenecid ethyl;

[0022] Its purity can reach above 99.0% (by HPLC); the impurity content is further detected by H-NMR to be 98.2%, which can be used as an impurity reference. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the structural formula of probenecid.

[0024] Figure 2 is the structural formula of probenecid ethyl.

[0025] Figure 3 shows the H-NMR detection of probenecid ethyl impurities.

[0026] Figure 4 shows the purity test of probenecid ethyl.

[0027] Figure 5 is the test spectrum of probenecid ethyl impurity in probenecid crude product.

[0028] Figure 6 is the test spectrum of probenecid ethyl impurity in probenecid raw material. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0030] Embodiment 1 A method for preparing probenecid ethyl, characterized in that the specific steps are as follows:

[0031] 1. Take a 250ml four-necked reaction bottle, add 100ml of anhydrous ethanol, and start stirring. Then add 20g of probenecid, and connect the four-necked bottle to a PTFE anchor stirrer, condenser, thermometer, and heating jacket;

[0032] 2. While stirring, slowly add 3 ml of concentrated sulfuric acid with a disposable dropper, turn on the heating jacket, and slowly raise the temperature until probenecid is completely dissolved and the reaction solution is clear. Add 8.4 g of 4a molecular sieve into the four-necked bottle;

[0033] 3. Continue to raise the temperature to reflux, reflux reaction for 5 hours, and the reaction solution gradually becomes turbid;

[0034] 4. After the reflux esterification reaction is completed, moisten a small amount of activated carbon with anhydrous ethanol, add it to the reaction bottle, reflux and decolorize for 30 minutes, and cool down after decolorization is completed;

[0035] 5. Filter the reaction solution, remove the activated carbon and 4a molecular sieve, and collect the filtrate; transfer the filtrate to a group of 15 ml vials, put the vials into the freeze dryer, close the freeze dryer door, and perform the freeze drying process.

[0036] 6. Pre-freeze to -30℃ and keep warm for 2 hours. Start sublimation, open the vacuum and heat to 0℃, keep warm for 3 hours; then increase the sublimation temperature to 5℃ and keep warm for 2 hours; continue to increase the sublimation temperature to 15℃ and keep warm for 3 hours; then continue to increase the sublimation temperature to 25℃ and keep warm for 2 hours. Finally, perform analytical drying and heat to 30℃, keep warm for 4 hours and end freeze-drying.

[0037] 7. The lyophilized powder is a white or off-white crystalline powder, and 21.2 g of probenecid ethyl is prepared.

[0038] Embodiment 2 A method for preparing probenecid ethyl, characterized in that the specific steps are as follows:

[0039] 1. Take a 250ml four-necked reaction bottle, add 160ml of anhydrous ethanol, and start stirring. Then add 28.5g of probenecid, and connect the four-necked bottle to a PTFE anchor stirrer, condenser, thermometer, and heating jacket;

[0040] 2. While stirring, slowly add 9 ml of concentrated sulfuric acid with a disposable dropper, turn on the heating jacket, and slowly raise the temperature until probenecid is completely dissolved and the reaction solution is clear. Add 9.0 g of 4a molecular sieve into the four-necked bottle;

[0041] 3. Continue to raise the temperature to reflux, reflux reaction for 7 hours, and the reaction solution gradually becomes turbid;

[0042] 4. After the reflux esterification reaction is completed, moisten a small amount of activated carbon with anhydrous ethanol, add it to the reaction bottle, reflux and decolorize for 30 minutes, and cool down after decolorization is completed;

[0043] 5. Filter the reaction solution, remove the activated carbon and 4a molecular sieve, and collect the filtrate; transfer the filtrate to a group of 15 ml vials, put the vials into the freeze dryer, close the freeze dryer door, and perform the freeze drying process.

[0044] 6. Pre-freeze to -45℃ and keep warm for 2 hours. Start sublimation, open the vacuum and heat to 0℃, keep warm for 5 hours; then increase the sublimation temperature to 10℃ and keep warm for 4 hours; continue to increase the sublimation temperature to 20℃ and keep warm for 2 hours; then continue to increase the sublimation temperature to 25℃ and keep warm for 4 hours. Finally, perform analytical drying and heat to 30℃, and end freeze-drying after keeping warm for 3 hours.

[0045] 7. The lyophilized powder is a white or off-white crystalline powder, and 30.36 g of probenecid ethyl is prepared.

[0046] The prepared probenecid ethyl ester, i.e., probenecid (sodium) impurity 4-(dipropylaminosulfonyl)benzoic acid ethyl ester, was tested by the Shanghai Institute of Pharmaceutical Industry (see Table 1 below).

[0047]

[0048] The content of this impurity is 98.2%; Figure 3 The results are shown in Table 2:

[0049]

[0050] The purity of the product was 99.35% as determined by HPLC. Figure 4 The results are shown in Table 3:

[0051]

[0052] The probenecid ethyl prepared by the method of the present invention was used as an impurity reference substance, and the crude probenecid product and the refined probenecid product were tested for the impurity by high performance liquid chromatography (HPLC). The impurity serial number in the HPLC spectrum was Z12. Inspection method: Accurately weigh the amount of probenecid, quantitatively dilute it with a diluent to prepare a solution containing 0.5 mg of probenecid per 1 ml, and use it as the test solution. The sample was injected and analyzed according to the test method. The results showed that the impurity was detected in the crude probenecid product (batch number B22209004), and the impurity peak area was 0.47% ( Figure 5 The results are shown in Table 4:

[0053]

[0054] This impurity was not detected in the probenecid product (batch number B12209002). Figure 6 ), the test data are shown in Table 5 below:

[0055] The test results show that the probenecid ethyl prepared by the method of the present invention meets the test requirements as an impurity reference substance and can be used for monitoring the impurities in probenecid raw materials and preparations and controlling product quality.

Claims

1. A method for preparing and purifying probenecid ethyl impurities, the specific steps are as follows: first, take a four-necked reaction bottle, add an appropriate amount of probenecid, add 5-10 times the volume ratio of anhydrous ethanol, connect the four-necked bottle with a tetrafluoro anchor stirrer, a condenser, a thermometer, and a heating jacket; then start stirring, add 2-10% of the volume of anhydrous ethanol with a disposable dropper, open the heating jacket, and slowly heat up until the probenecid is completely dissolved and the reaction solution is clear; it is characterized in that:

1. Add a certain amount of 4a molecular sieve to a four-necked bottle, the amount of which is 0.3-0.5 times the amount of probenecid; continue to heat to reflux, reflux reaction for 5-10 hours, the reaction solution gradually becomes turbid; after the reflux esterification reaction is completed, wet an appropriate amount of 3-5% activated carbon, which is the amount of probenecid, with anhydrous ethanol, add it to the reaction bottle, reflux decolorization for 20-30 minutes, and cool down after decolorization is completed; filter the reaction solution, filter out the activated carbon and 4a molecular sieve, and collect the filtrate; 2. Transfer the filtrate to a group of 15ml vials, put the vials into a freeze dryer, and close Close the freeze dryer door and start the freeze drying program; first pre-freeze to minus 30-45°C, keep warm for 2-4 hours, start sublimation, open the vacuum and heat to 0-5°C, keep warm for 3-5 hours; then increase the sublimation temperature to 5-10°C and keep warm for 2-4 hours; continue to increase the sublimation temperature to 15-20°C and keep warm for 1-3 hours; then continue to increase the sublimation temperature to 20-25°C and keep warm for 1-4 hours; finally, perform analytical drying and heat to 30°C, keep warm for 2-4 hours and end freeze drying; the freeze-dried powder is white or off-white crystalline powder, and probenecid ethyl is prepared.

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