RU2641967C1 - Method for production of lappaconitine hydrobromide and lappaconitine - Google Patents

Abstract

FIELD: pharmacology.

SUBSTANCE: method for production of lappaconitine hydrobromide and lappaconitine by extracting aconite roots with 70-80% by volume aqueous acetone, acetone distilling off from the extract, alkalizing, alkaloids extraction with an organic solvent and then distillation, while benzene or toluene are used as an organic solvent for alkaloids extraction from the alkaline solution, after solvent distillation, the residue is divided into parts, with one part of the residue treated with acetone or alcohol to release lappaconitine, the other part of the residue trested with ethanol and alcoholic solution of hydrobromic acid to release lappaconitine hydrobromide.

EFFECT: increased yield and reduced number of process stages.

5 ex

Description

The invention relates to the pharmaceutical industry, in particular to a method for producing medicinal substances from plant materials, and for the production of lappaconitine hydrobromide and its intermediate product-lappaconitine used in medical practice.

Describes how to obtain lappaconitine:

from the roots of Aconitum septentrionale [Marion L., Fonzer L., Wilkins C.K., Boca Jr and J.P., Sandberg F., Thorsen R., Linden E. // Can J. Chim. 1967. Vol. 45. P. 969-973] 4-fold extraction of crushed raw materials with methanol at room temperature and stirring, evaporating the combined extract in vacuum, dissolving the residue in 2 N. sulfuric acid, filtering the solution, washing the filtrate with ether, alkalizing with sodium carbonate, extraction with chloroform, evaporating the extract, dissolving the residue in benzene, chromatography on alumina, eluting with benzene, evaporating the eluate, crystallizing the residue from ether;

from the roots of Aconitum septentrionale by treating the crushed material with hexane, extraction with 80% ethanol, distilling off the solvent, partitioning the residue between chloroform and 2% sulfuric acid, alkalizing the acid layer with sodium hydroxide to pH 12, extraction with chloroform, evaporation, dissolving the residue in acetone by cooling, separating the crystalline precipitate, obtaining lappaconitine by double recrystallization from a mixture of chloroform-acetone, and also by chromatography of the evaporated combined mother liquors on alumina in hexane - ietilovy ether - ethanol with increasing polarity lappaconitine and isolation of fractions 60-80% ether-hexane [Ross A., Pelletier S.W.//Tetrahedron. 1992. Vol. 48. No. 7. P. 1183-1192];

from the roots of Aconitum excelsum (synonym for Aconitum leucostomum) by treating the crushed raw materials with a 5% soda solution, exhaustive extraction with dichloroethane, extracting the dichloroethane solution with 5% sulfuric acid, adding ether to the sulfuric extract and alkalizing with a 5% solution of soda, filtering precipitate (part A), extraction of the mother liquor with ether (part B), dissolving part A in 5% hydrochloric acid and adding an excess of saturated sodium perchlorate solution, crystallizing lappaconitine perchlorate from methanol; by dissolving part B in 5% sulfuric acid, fractional alkalization, followed by extraction with ether and evaporation, an additional amount of lappaconitine is obtained [Platonova TF, Kuzovkov AD, Massagetov P.S. // ZhOKh. - 1958, p. 258-261].

In the considered works, there is no detailed description of extraction, information about the purity of the product, the process of isolation of lappaconitine is multi-stage, aggressive media are present, and a large number of organic solvents are used.

Known methods for producing lappaconitin hydrobromide through the intermediate allocation of lappaconitin from grass or roots of white aconite, northern aconite. Thus, a method is known in which the grass of white aconite is poured with an aqueous solution of sulfuric or acetic acid and extracted in a battery system. A NaOH solution is added to the resulting sulfate extract to a slightly acidic reaction. Then activated carbon is added to the solution and mixed. The hot solution is filtered off from coal and soda is added to the filter until a pH of 9-9.5 is obtained. The alkaline solution is extracted with chloroform until a negative reaction to alkaloids. The resulting chloroform extract was evaporated and chromatographed through a glass column with an alumina sorbent, eluting with ethyl acetate. After alumina, the eluent was evaporated, acetone was added to the residue and left in a cool place for 12 hours. Then the precipitate of the base of lappaconitine is filtered off. The base of lappaconitine is treated with an alcoholic solution of hydrobromic acid and get technical lappaconitine hydrobromide, which is once recrystallized in methanol and get pharmacopoeial lappaconitine hydrobromide [RU 2295355 02.20.2006].

A method for producing lappaconitine hydrobromide [RU 2545799 06/20/2014], which is carried out by extraction of the roots or grass of white aconite (Aconitum leucostomum) or the roots or grass of northern aconite (Aconitum septentrionale) with methylene chloride in an apparatus for continuous extraction, followed by purification from impurities, is also proposed. flash chromatography (option 1), or extraction of plant materials with a polar organic solvent, followed by removal from the extract of a polar organic solvent (option 2), alkalization and extraction of the floor scientific residue with methylene chloride followed by purification of the extract by flash chromatography. As the sorbent for flash chromatography, alumina or silica gel is used. In this case, the adsorbed alkaloids are eluted with an organic solvent, such as acetone or ethyl acetate. The resulting ethyl acetate solution of lappaconitine base is evaporated, dissolved in acetone, and the acetone solution of lappaconitine base is treated with a solution of hydrobromic acid in acetone, lappaconitine hydrobromide is obtained and pharmacopoeial purity lappaconitine hydrobromide is obtained by recrystallization from ethanol.

Known methods for producing lappaconitine hydrobromide (allapinin) with various methods of processing water residues obtained after evaporation of alcohol or acetone extracts of grass or roots of white aconite (wrestler), northern aconite (wrestler).

A known method of producing allapinin (lappaconitine hydrobromide) from white aconite grass, which consists in the fact that the crushed raw materials are repeatedly extracted with 80% ethyl alcohol at room temperature, the combined extracts are evaporated to an aqueous residue, which is alkalinized to pH 9 and treated with chloroform; alkaloids are extracted from chloroform extraction with a 5% sulfuric acid solution, the obtained sulfate extracts are alkalinized to pH 9 and treated with chloroform, the chloroform extraction is evaporated to dryness, the dry residue is the amount of alkaloids (in the form of bases) dissolved in ethyl alcohol, 5% alcohol solution of hydrobromic acid is added to pH 2; released technical allapinin (lappaconitine hydrobromide) is separated and recrystallized from methyl alcohol [SU 1196004 12/07/1985].

There is also a method of producing allapinin (lappaconitine hydrobromide) from the roots and rhizomes of northern aconite, which consists in the fact that the crushed raw materials are extracted repeatedly with 75-80% ethanol, the combined extracts are evaporated to an aqueous residue, which is alkalinized to pH 9-10, the precipitate formed is a technical precipitate the amounts of alkaloids are separated, dissolved in a 10% solution of sulfuric acid, the resulting solution is purified from ballast substances by treatment with chloroform, after which the purified solution is alkalinized to pH 9-10 and chlorine alkaloids are recovered Contents, the chloroform extract is evaporated to dryness; dry residue-the amount of alkaloids (in the form of bases) is treated with ethanol, the precipitated precipitate of the purified amount of alkaloids is separated, mixed with ethanol, 5% alcohol solution of hydrobromic acid is added to pH 3; released technical allapinin (lappaconitine hydrobromide) is separated and recrystallized from methyl alcohol. The yield of the drug is 0.525% by weight of air-dried raw materials or 75% of the content in raw materials [RU 2039568 07.20.1995].

A known industrial method of producing allapinin (lappaconitine hydrobromide), which provides for the grinding of plant materials - rhizomes with the roots of a northern fighter or white fowl rhizomes and roots, the production of technical allapinin (lappaconitine hydrobromide), for which four times the extraction of alkaloids from raw materials using ethyl alcohol on a battery of three extractors with obtaining water-alcohol extracts and using the first extract from each download of each extractor for evaporated I, and the second, third, and fourth extracts of each load, as an extractant for the first, second, and third extracts of the next loads, the fourth extraction of which is carried out with alcohol, evaporation of the first water-alcohol residue from the ballast substances under vacuum, and purification of the resulting aqueous bottoms ethyl acetate, with acidification of an aqueous extract saturated with ethyl acetate, an aqueous solution of hydrobromic acid and repeated extraction with chloroform while controlling the pH of the medium, which should not values greater than the operation 1.5-2, evaporation of chloroform extracts in vacuo and the displacement of chloroform ethyl alcohol to form a slurry Allapinin (lappaconitine hydrobromide) which is filtered, washed with ethyl alcohol and dried, and then analyzed [RU 2518742 09.20.2013].

A known method of producing allapinin (lappaconitine hydrobromide), which includes the extraction of the roots and rhizomes of the northern fighter 80% ethanol in two reactors, the first water-alcohol extraction from each reactor is directed to evaporation; the second, third and fourth extracts are used for the first, second and third extraction of raw materials, respectively, in another reactor, and 80% ethanol is fed to each reactor for the fourth extraction, and ballast substances are extracted by treating the aqueous bottoms with ethyl acetate and adding a solution of hydrobromic acid to it and extraction of alkaloids (in the form of salts) with chloroform, while technical allapinin (lappaconitine hydrobromide) is isolated from chloroform extraction by adding ethyl alcohol by evaporation AANII then recrystallized from methyl alcohol [RU 2238103 20.10.2004].

The disadvantages of all these methods are:

multi-stage process

the multiplicity of the extraction process

losses at the ballast recovery stage

risk of equipment corrosion;

the possibility of hydrolysis to deacetyl lappaconitine

In all these methods, there is a stage of removal of ballast substances impurities either using sulfuric acid through the formation of sulfate salts (corrosion factor) or by extra extraction (additional consumption of solvents), or solid carriers for extraction or recrystallization (the need for regeneration).

There is also a method of producing allapinin (lappaconitine hydrobromide) from the roots and rhizomes of the northern wrestler, namely, the grinding of raw materials is carried out in the presence of sorbents, or mineral salts, or oxides, or solid organic acids, or their salts, or carbohydrates, or urea in machining by acting balls at acceleration of 80-800 m / s in gravitational or vibration-centrifugal activators. The solid machined product is treated with water, the solid and liquid phases are separated, the filtrate is made alkaline to pH 10-11 and the alkaloids are removed with a chlorine-containing organic solvent. The resulting extract was evaporated to dryness, the amount of alkaloids was dissolved in alcohol, 2% hydrobromic acid was added, and allapinin (lappaconitine hydrobromide) was obtained with a yield of 0.7% by weight of raw materials [RU 2176919 12/20/2001].

The disadvantages of the method in the case of using in the process of mineral salts, or organic acids, or oxides, or urea, is the need for their disposal and treatment of wastewater containing additional impurities in the form of these substances.

Note that in most works the yield of the final product is given as one of the proofs of the effectiveness of the proposed method in comparison with literary analogues, which is not correct, since in various samples of plant materials the natural content of lappaconitine varies widely. For the correct comparison of different isolation schemes, it is necessary to use the same sample and indicate the method for determining the purity of the product (titration, HPLC, other methods), since the accuracy of these evaluation methods is different.

Closest to the claimed method is a method for producing lappaconitin hydrobromide, in which the extraction of the roots or grass of northern aconite (Aconitum septenrionale), roots or grass of white aconite (Aconitum leucostomum) is carried out with 50-80% aqueous acetone with the removal of impurities from one stripped off and acidified extract by a single treatment with dichloroethane, isolation of alkaloids from an alkaline solution by 2-3-fold extraction with dichloroethane or ethyl acetate. Lappaconitin is obtained by distillation of the organic solvent from the extract, addition of acetone and crystallization of the residue from acetone. Adding to a suspension of lappaconitine in alcohol a 10% alcohol solution of HBr to pH 3, get lappaconitine hydrobromide [RU 212334720.12.1998].

The disadvantages of the method include the use of sulfuric acid (corrosion factor, the possibility of hydrolysis to deacetyl lappaconitine).

The problem to which the claimed invention is directed, is to increase the yield of the target product and reduce the number of process steps

The problem is achieved by the development of a method for producing lappaconitine hydrobromide and lappaconitine based on a new processing of extracts, which allows to increase the yield and reduce the number of process steps.

The essence of the claimed technical solution is as follows: the crushed plant material is extracted with 70-80% (by volume) aqueous acetone. The organic solvent is distilled off from the combined extracts, the aqueous residue is alkalinized to pH 8-9 and the alkaloids are extracted with benzene or toluene, then the organic solvent is distilled off and the residue is treated with acetone or ethanol, followed by isolation of lappaconitine, or ethanol and an alcoholic solution of hydrobromic acid with isolation of lappaconitine hydrobromide.

Using the proposed method in comparison with the known provides the following advantages: reducing the number of process steps and increasing product yield, which is achieved by using at the stage of extraction from an alkaline solution of a more selective extractant - benzene or toluene and eliminates acidification and recovery of ballast substances. Residual amounts of benzene or toluene can be removed by distillation of the azeotrope with alcohol. The use of a more selective solvent leads to a reduction in the number of stages and the duration of the process, lower energy consumption, economy of solvents without compromising the quality of the emitted product, and also increases the yield of the target product by reducing losses associated with the stage of removal of ballast substances. The absence of an acidification step reduces the risk of hydrolysis of lappaconitine to deacetyl lappaconitine and corrosion of the equipment.

The invention is illustrated by the following examples in comparison with the prototype for several lots of roots of northern aconite with different contents of lappaconitine:

Example 1

Extracted 100 g of the crushed roots of northern aconite (sample 1) with 70% (vol.) Aqueous acetone by infusion at room temperature (5 plums, total volume 1.0 l). The aqueous acetone solution was filtered, divided into two equal parts and processed as described below.

части экстракта отгоняли ацетон, водный остаток подщелачивали насыщенным раствором соды до рН 8-9, экстрагировали пятикратно бензолом (суммарный объем бензольного экстракта 400 мл, суммарное соотношение растворов водно-щелочной - бензольный ≈1:3). Объединенный бензольный экстракт промывали 30 мл воды, сушили сернокислым натрием, фильтровали, упаривали, к остатку прибавляли 5 мл ацетона и оставляли для кристаллизации. Выпавший лаппаконитин отфильтровывали, промывали минимальным количеством ацетона (2 мл). Получили 0.551 г технического лаппаконитина с чистотой 89% по данным ВЭЖХ (0.98% от в/с сырья).and from

portions of the extract were distilled off with acetone, the aqueous residue was alkalinized with a saturated soda solution to pH 8-9, extracted five times with benzene (total volume of benzene extract 400 ml, total ratio of aqueous-alkaline solutions - benzene ≈1: 3). The combined benzene extract was washed with 30 ml of water, dried with sodium sulfate, filtered, evaporated, 5 ml of acetone was added to the residue and allowed to crystallize. The precipitated lappaconitine was filtered off, washed with a minimum amount of acetone (2 ml). Received 0.551 g of technical lappaconitine with a purity of 89% according to HPLC (0.98% of w / s raw materials).

часть экстракта обрабатывали в условиях прототипа - ацетон отгоняли, водный остаток подкисляли 3% серной кислотой до рН 3, однократно экстрагировали 30 мл дихлорэтана для удаления балластных веществ, кислый водный раствор подщелачивали насыщенным раствором соды до рН 8 и 5-кратно экстрагировали дихлорэтаном порциями по 80 мл, сушили сернокислым натрием, фильтровали, упаривали, к остатку прибавляли 5 мл ацетона и оставляли для кристаллизации. Выпавший лаппаконитин отфильтровывали, промывали минимальным количеством ацетона (2 мл). Получили 0.563 г технического лаппаконитина с чистотой 82% по данным ВЭЖХ (0.92% от в/с сырья).b)

part of the extract was processed under the conditions of the prototype — acetone was distilled off, the aqueous residue was acidified with 3% sulfuric acid to pH 3, 30 ml of dichloroethane was extracted once to remove ballast substances, the acidic aqueous solution was made alkaline with saturated soda solution to pH 8, and extracted with 80 times 5 times with dichloroethane ml, dried with sodium sulfate, filtered, evaporated, 5 ml of acetone was added to the residue and left to crystallize. The precipitated lappaconitine was filtered off, washed with a minimum amount of acetone (2 ml). Received 0.563 g of technical lappaconitine with a purity of 82% according to HPLC (0.92% of w / s raw materials).

Example 2

Extracted 150 g of the crushed roots of northern aconite (sample 2) with 70% (vol.) Aqueous acetone by infusion at room temperature (5 plums, total volume 1.35 L). The water-acetone solution was filtered, divided into three equal parts and processed as described below.

a) Acetone was distilled from 450 ml of the extract, the aqueous residue was basified with a saturated soda solution to a pH of 8-9, extracted five times with benzene (total volume of benzene extract 500 ml, total ratio of volumes of aqueous-alkaline solutions: benzene ≈1: 3.3). The combined benzene extract was washed with 50 ml of a saturated sodium chloride solution, dried with sodium sulfate, filtered, the solvent was distilled off, 5 ml of acetone was added to the residue, and allowed to crystallize. The precipitated lappaconitine was filtered off, washed with a minimum amount of acetone (3 ml). Received 0.486 g of technical lappaconitine with a purity of 90.5% according to HPLC. (0.88% of premium raw materials).

b) 450 ml of the extract was treated under the conditions of the prototype — acetone was distilled off, the aqueous residue was acidified with 3% sulfuric acid to pH 3, 30 ml of dichloroethane was extracted once to remove ballast substances, the acidic aqueous solution was made alkaline with saturated soda solution to pH 8-9 and 5-fold extracted with 100 ml portions of dichloroethane, dried with sodium sulfate, evaporated, 5 ml of acetone was added to the residue and allowed to crystallize. The precipitated lappaconitine was filtered off, washed with a minimum amount of acetone (2 ml). Received 0.459 g of technical lappaconitine with a purity of 90.4% according to HPLC (0.83% of w / s of raw materials).

c) Acetone was distilled from 450 ml of the extract, the aqueous residue was basified with a saturated soda solution to a pH of 8-9, extracted five times with benzene (total volume of the benzene extract was 500 ml, the total water-alkaline-benzene ratio was ≈1: 3.3). The combined benzene extract was washed with 50 ml of a saturated solution of sodium chloride, dried with sodium sulfate, filtered, the solvent was distilled off, 5 ml of alcohol was added to the residue and distilled off to remove benzene residues, 5 ml of alcohol and 8 ml of 4% alcohol solution of hydrobromic acid were added to the residue, kept for 5 hours, then the precipitate was filtered off, washed with 5 ml of alcohol, dried in air. Received 0.576 g of lappaconitine hydrobromide, in which (according to HPLC) the content of lappaconitine is 76%.

Example 3. Extracted 1.75 kg of crushed roots of northern aconite (sample 3) 75% (by volume) with aqueous acetone by infusion at room temperature (5 plums, total volume 17.3 l). The water-acetone solution was filtered, 400 ml aliquots were taken and processed as described below.

a) Acetone was distilled from 400 ml of a water-acetone extract, the aqueous solution (100 ml) was made alkaline with a saturated soda solution to pH 8-9, extracted five times with benzene (total volume of the benzene extract was 500 ml, the total ratio of water-alkaline was benzene ≈1: 4 ) The combined benzene extract was washed with 50 ml of water, dried with sodium sulfate, filtered, the solvent was distilled off, 5 ml of alcohol was added to the residue and distilled off again to remove benzene residues, 5 ml of alcohol and 8 ml of 4% alcohol solution of hydrobromic acid were added to the residue, kept in for 5 hours, then the precipitate was filtered off, washed with 3 ml of alcohol, dried in air. Received 1.408 g of lappaconitine hydrobromide, in which (according to HPLC) the content of lappaconitin is 80.3%. The output of lappaconitine hydrobromide 3.2% of the premium raw materials.

b) Acetone was distilled from 400 ml of a water-acetone extract, the aqueous residue (100 ml) was acidified with 3% sulfuric acid to pH 3, 30 ml of dichloroethane was extracted once to remove ballast substances, the acidic aqueous solution was made basic with a saturated soda solution to pH 8 and 5- was extracted repeatedly with dichloroethane (total volume of benzene extract 500 ml, total ratio of aqueous-alkaline solutions - dichloroethane ≈1: 4). The combined extract was dried with sodium sulfate, filtered, the solvent was distilled off, 5 ml of alcohol was added to the residue and distilled off again to remove dichloroethane residues, 5 ml of alcohol and 8 ml of a 4% alcohol solution of hydrobromic acid were added to the residue, kept for 5 h, then the precipitate filtered off, washed with 3 ml of alcohol, dried in air. Received 1.208 g of lappaconitine hydrobromide, in which (according to HPLC) the content of lappaconitine is 79.2%. The yield of lappaconitine hydrobromide is 2.7% of the raw material.

The following examples illustrate the treatment of water-acetone extracts with the release of lappaconitine or lappaconitine hydrobromide from various samples of northern aconite roots according to the proposed method.

Example 4

a) Acetone was evaporated from a 250 ml aliquot of the water-acetone extract (root sample 4), the aqueous residue was made alkaline with a saturated soda solution, and 5 times extracted with 40 ml portions of benzene, the combined extract was washed with 30 ml of water, dried with sodium sulfate, and the solvent was removed by rotor distillation evaporator, 10 ml of alcohol was added to the residue, re-evaporated to remove traces of benzene, 4 ml of alcohol was added, kept for 5 h, the precipitated lappaconitine was filtered off, washed with a minimum amount of alcohol (2 ml), dried in air , technical lappaconitin was analyzed by HPLC. The yield of technical lappaconitine 1.78 g, purity 94.0%.

b) Acetone was evaporated from a 250 ml aliquot of the water-acetone extract (root sample 4), the aqueous residue was made alkaline with a saturated soda solution and 5 times extracted with 40 ml portions of benzene, the combined extract was washed with 30 ml of water, dried with sodium sulfate and evaporated on a rotary evaporator , 10 ml of alcohol was added to the residue, re-evaporated to remove traces of benzene, 10 ml of a 4% alcohol solution of hydrobromic acid were added, kept for 5 h, the precipitated lappaconitine hydrobromide was filtered off, washed were minimal m of alcohol (2 ml), dried in air, technical lappaconitine hydrobromide was analyzed by HPLC. Received 2.07 g of lappaconitine hydrobromide with a content of lappaconitine 81.4%.

c) Acetone was evaporated from a 250 ml aliquot of the water-acetone extract (root sample 4), the aqueous residue was acidified with 3% sulfuric acid to pH 3, 20 ml were extracted once with dichloroethane to remove ballast substances, the acidic aqueous solution was made basic with a saturated soda solution to pH 8 5 -extracted with 40 ml portions of dichloroethane, the combined extract was washed with 30 ml of water, dried with sodium sulfate, evaporated on a rotary evaporator, 10 ml of alcohol was added to the residue, re-evaporated to remove traces of benzene, 4 ml of alcohol was added and was maintained for 5 hours, lappaconitine precipitate was filtered off, washed with a minimal amount of alcohol (2 mL), air dried, technical lappaconitine analyzed by HPLC. The yield of technical lappaconitine 1.65 g, purity 84.5%.

Example 5

a) Acetone was evaporated from an aliquot (500 ml) of water-acetone extract (root sample 5), the aqueous residue was made alkaline with saturated soda solution and extracted with 80 ml of toluene 4 times, the combined extract was washed with 20 ml of water, dried with sodium sulfate and evaporated on rotary evaporator, 10 ml of alcohol was added to the residue, re-evaporated to remove traces of toluene, 5 ml of alcohol was poured, kept for 5 hours, the precipitated lappaconitin was filtered off, dried in air, and technical lappaconitin was analyzed by HPLC. The yield of technical lappaconitine 3.305 g, a purity of 84.2%

b) Acetone was evaporated from an aliquot (500 ml) of the water-acetone extract (root sample 5), the aqueous residue was acidified with 3% sulfuric acid and 30 ml of chloroform was extracted once, the acidic aqueous layer was made basic with a saturated soda solution to pH 8-9 and 4- was extracted repeatedly with 80 ml portions of chloroform, the combined extract was dried with sodium sulfate, evaporated on a rotary evaporator, 5 ml of alcohol was added to the residue, it was kept for 5 h, the precipitated lappaconitine was filtered off, dried in air, and analyzed by HPLC. The yield of technical lappaconitine 2.992 g, purity 83.9%.

Claims (1)

The method of producing lappaconitine hydrobromide and lappaconitine by extraction of the roots of northern aconite with 70-80%, by volume, aqueous acetone, distillation of acetone from the extract, alkalization, extraction of alkaloids with an organic solvent followed by distillation, characterized in that as an organic solvent for extraction alkaloids from an alkaline solution use benzene or toluene, after distillation of the solvent, the residue is divided into parts, while one part of the residue is treated with acetone or alcohol with the release of lappacon Itin, another part of the residue is treated with ethanol and an alcoholic solution of hydrobromic acid with the release of lappaconitine hydrobromide.