FI85855B - Process for the preparation of isosilybin free silibinin and a silibinin-containing medicinal product - Google Patents

Abstract

The invention relates to a process for the preparation of isosilybin free silibinin of the formula I <IMAGE> by extracting the dried fruit of Silybum marianum L. Gaertn plant.

Description

85B5S

Method for the preparation of isosylybin-free silibin and a drug containing silibin - Förfarande för framställ-Ning av isozylybri-free silibin

By dividing the separated application 854536 Avdelad ur patent claim 854536

The invention relates to a process for the preparation of silibinin and to medicaments containing this compound.

Marianohdake - Silybum marianum (L.) Qaertn. (Carduus marianus L.) - is a medicinal plant known since ancient times. R. Mijnster, cf. Dissertation R. Munster, Munich, 1966, isolated one component, silybinin, from f 1 avignans present in the fruits of this plant. The chemical structure of this compound has been elucidated by A. Pelter and R. Hänsel in Tetrahedron Letters, London, Volume 25, pages 2911-2916 (1968).

Silybinine, formerly also referred to as silymarin I, is known to be a valuable hepatotherapeutic agent, cf. DE-AS 17 67 666. For example, DE-AS 19 23 082 describes a technical process for the preparation of silybinine (silymarin I).

As early as 1974, H. Wagner, P. Diesel, and M. Seitz, f Arzne imi tte 1 f orschung, Volume 24 (4), pages 466-471, assumed that there were two pa i kka i someer i ä, namely silybinine and i sos i 1 yb inin. This assumption has been clarified and experimentally confirmed by A. Arnone, L. Merliini, and A. Zanarotti, Journal Chemical Society Chem.comm., 1979, Volume 16, pages 696/97. ... Accordingly, the known silybinine consists of two different compounds, namely compounds having the following structures: A and B: 85855 2 OH O - 02 (A) Si 1ibini ini 3

—CH2 0H

OB O

(B) Isosilybin From these structural formulas, it can be seen that these compounds are positional isomers. The INN of the compound of formula (A) is currently called silibinin. This term for a compound of formula (A) is also used in the present application.

To date, both of the above-mentioned compounds A and B have been separated and prepared only in analytical amounts, and nothing is known about the pharmacological effects of the individual isomers.

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It is therefore an object of the invention to provide a process for the preparation of isocybinine-free silibin and siibinin-containing pharmaceuticals.

The invention therefore relates to a process for the preparation of siibinin of the formula t in which Silybum marianum L. Qaertn. the main part of the fat is removed from the dried fruit of the plant by blasting the cells with high mechanical pressure, after which the pressed residue, which still has a residual oil content of 5 to 10%, is extracted with ethyl acetate, the ethyl acetate is evaporated and the dry residue is dissolved in 2% by weight, is 95 parts by weight of methanol, 5 parts by weight of water and 100 parts by weight of petroleum ether (b.p. 40-60 ° C), to a lower phase consisting of methanol and water, the flake-like dry residue is subjected to multiple, uniform countercurrent extraction in this solvent system, the upper phase / the total flow ratio of the lower phase is kept equal to 1: 1, and then the 70-80 * polyhydroxyphenylchromanone mixture (silylarin I -1V = silymarin I-IV group) is isolated from the outflowing lower phase by evaporation to dryness in vacuo as a brownish powder , for which method characterized in that 4 85855 a) one part by weight of the obtained brownish powder, hereinafter referred to as the amount, is suspended in 0.7 to 1.5 parts by weight of ethyl acetate saturated with water, and the resulting suspension is allowed to stand for 1-2 days, and the precipitate is separated by suction 11a, b) the precipitate obtained is washed with 0.07 to 0.15 parts by weight of cold ethyl acetate saturated with water and dried in vacuo at 30 to 50 ° C, c) this product is dissolved in 30 to 50 parts by weight of dry (anhydrous) ethyl acetate at reflux, treated with 0.4 parts by weight of activated carbon at reflux for 2 hours, filtered and the filtrate evaporated at 30-50 ° C under vacuum to about 1/12 of the amount of solvent used for dissolution, d) 0.5 to 0 is added to the concentrate, 8 parts by weight of ethyl acetate saturated with water, the precipitated silibinin is filtered off after 5-10 hours and e) the silibinin is resuspended, pre-dried under vacuum at 30-50 ° C , the pre-dried product is ground and re-dried at 30-50 ° C under vacuum.

The brownish powder or crude silymarin used as starting material in step a) is a mixture of siymarins I to IV. Treatment of crude silymarin with ethyl acetate saturated with water essentially separates the major part of silymarins 11 to IV (silibinin is silymarin I) and 20 to 30% of the crude silymarin excipients and part of isocybin. In this way, in step b), 80 to 85% of crude libinine are obtained, depending on the quality of the crude silymarin (calculated from the content of crude silymarin) at a concentration of 80 to 84%.

According to the prior art, crude libinin is described as a mixture of isosilbine and silibinin in a ratio of about 1: 4.

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In steps c) to e), the major part of the isosilybin is separated from the silibin and the residues of the other ingredients mentioned above are separated.

A particular advantage of this separation method is the use of a single solvent, namely ethyl acetate, which in part contains different amounts of water. In this case, it is essential to use anhydrous ethyl acetate in step c) and ethyl acetate saturated with water in step d). The process according to the invention gives silibinin in a yield of 79-85% (based on the siibinin contained in the crude 1binin) and with a siibinin content of 96-98%.

A particularly preferred embodiment of the process according to the invention consists in a) suspending one part by weight of a brownish powder in 0.9 parts by weight of ethyl acetate saturated with water, allowing to stand for 48 hours at room temperature and separating the precipitate obtained by suction, b) washing with 0.09 parts cold, water-saturated ethyl acetate and dried for 48 hours at 40 ° C under vacuum, c) the product obtained is dissolved in 36 parts by weight of dry ethyl acetate at reflux, heated at reflux with 0.36 parts by weight of activated carbon for 2 hours, filtered and evaporated at 50 ° C in vacuo to 1/12 part of the amount of solvent used for dissolution, d) 0.6 parts by weight of ethyl acetate saturated with water are added to the concentrate at room temperature, allowed to stand for 12 hours at room temperature and the precipitated product is filtered off 11a, e) , 8 parts by weight of technical ethyl acetate and filtered, pre-dried under vacuum at 40 ° C for 24 hours, ground and post-dried under vacuum at 40 ° C for 48 hours.

6 85855 I sosi lybi iniva-free si 1ibinfin was found to be very well suited for pharmaceutical purposes. Surprisingly, it was found to have substantial advantages over other known ingredients in Silybum-marianum extracts. It is particularly well suited for the treatment of cirrhosis of the liver and toxic-metabolic liver damage. It can also be used prophylactically so that the described lesions do not occur at all.

The invention therefore also relates to medicaments containing siibinin. They are most often used systemically, for example as pills, capsules, solutions, in conventional carriers and possibly in combination with conventional excipients. The daily dose for an adult is about 50 to 500 mg, depending on the condition of the patient and the severity of the symptoms.

Example

Preparation of isosilybin-free silibin: 1 kg of a mixture of polyhydroxyphenylchromanone (silymarin I to IV = silymarin group I to IV; content about 70%) as a brownish powder, also referred to herein as crude silymarin, obtained from DE-AS 19 23 082, incorporated herein by reference. lines 14 to 19, is suspended in 1 liter of water-saturated acetic acid ester over 30 minutes using a Turrax mixer. After standing for 48 hours at room temperature, the precipitate is filtered off with suction, washed with 100 ml of cold, water-saturated acetic acid ester and dried under vacuum for 48 hours at 40 ° C. The yield of this intermediate crude libinin is 80-85%, depending on the quality of the crude silymarin, based on the siibinin content of the crude lymarin and is 80-84%.

The crude 1ibinin is dissolved in 40 liters of dry acetic acid ester at reflux, boiled for 2 hours under reflux with 360 g of activated carbon, filtered and evaporated at 50 [deg.] C. in vacuo to a total volume of 3330 ml. To this solution is added, with vigorous stirring at room temperature, 667 ml of water-saturated acetic acid ester. After 1-3 hours, crystallization of silibinin begins, allowed to stand overnight, then separated by filtration, suspended twice in 5-10 minutes, used! 1200 ml of technical grade acetic acid ester, filtered again and pre-dried under vacuum at 40 oC for 24 hours. After grinding, dry for 48 hours at 40 ° C under vacuum. Based on the siibinin contained in the crude 1ibinin, the yield of silibinin is 79-85% and the concentration is 96-98.5% depending on the quality of the crude 1ibinin.

Clinical trials si 1ibinin 1lä

Toxic liver damage has increased very sharply in recent decades. The cause of damage is most often, as in the past, alcohol.

Controlled studies showed that silibinin was superior to placebo or other comparators. A double-blind study examined 66 patients with alcohol-toxic liver injury, silibinin (n = 31) versus placebo (n = 35) in a statistical manner.

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Statistically evaluated results showed that silibin is significantly better than Placebo. Si It was striking then that there were substantially shorter healing times compared to Placebo. In another double-blind study of 76 patients, including 39 or silibinin and 37 controls, the differences were very significant in favor of silibinin.

In the context of abdominal surgery, a study of the hepatotoxic effects of anesthesia showed that preoperative administration of silibinin significantly reduced the postoperative growth of liver enzymes in the blood. Silibinin can also be used effectively to prevent the increase in liver damage caused by certain drugs. This could be demonstrated, for example, in the case of phenylhydantoin-induced hepatosis, where, despite the prescribing of completely necessary anticonvulsants, concomitant administration of silibinin normalizes all laboratory values within a short time.

Further studies in patients with schizophrenia and severe liver damage due to chlorbromazine prescription also showed a positive effect of silibinin. Other experiments included the inhibition of the hepatotoxic effects of chloroquine or asparaginase. In the case of occupational liver damage, all treated patients were able to substantially improve their pathologically elevated laboratory values, regardless of the cause or possible additional diseases.

In addition, there is ample evidence that silibinin also produces substantial improvements in chronic inflammatory liver disease and cirrhosis. For example, patients with cirrhosis of the liver were treated as a long-term study in a statistical double-blind study of 9,855,55 silibinin versus placebo. Survival time was the main criterion used to assess the therapeutic effect. Silibinin was then clearly superior to placebo.

Comparison of the effect of silibinin and isosilybin and silybin (a mixture of silibin and isosilybin) in a palloid and praseodymine toxicity model in mice after intravenous administration.

The anti-hepatotoxic effect of silibinin, isosilybin and silybin was studied as N-methylglucamine salts at nanos 50 and 100 mg kg-1 based on silibinin after intravenous administration to mice in a palloid and praseodymium poisoning model. The test substance was applied 1 hour before phalloidin or 1 hour before and 6 hours, 24 hours and 48 hours after praseodymium. Survival was assessed in phalloidin poisoning and various serum and liver parameters in praseodymium poisoning 72 hours after poisoning.

In phalloidin poisoning, the survival rate after silibinin was 100 * at both doses, with the other agents not exceeding 40% survival of untreated, damaged controls.

In praseodymium poisoning, isosilybin proved to be intolerable, so a dose of 100 mg kg-1 had to be divided into two applications.

Claims (2)

10 85855 Patent Claims A process for the preparation of isosilybin-free silibin having the formula ot o Silybum marianum L. Gaertn. from the dried fruit of the plant, most of the fatty oils are removed by blasting the fruit cells with high mechanical pressure, after which the press residue, still having a residual oil content of 5 to 10 35, is extracted with ethyl acetate, the ethyl acetate is evaporated, and the dry residue 95 parts by weight of methanol, 5 parts by weight of water and 100 parts by weight of petroleum ether (b.p. 40-60 [deg.] C.), to a lower phase of methanol and water, the flake-like solids are removed by high-temperature centrifugation and the dry residue is subjected to a multi-solvent. , a uniform countercurrent extraction, wherein the volume ratio of the total flow of the γ1phase / α1 phase is kept equal to 1: 1, and then the outflow. "A mixture of chromone i (chromone I to IV = silymarin group I to IV) of a chromone i mixture which is evaporated to dryness in vacuo is 11a * -" "" : characterized in that: **; (a) one part by weight of a brown powder obtained, followed by -; * j '. this is referred to as an amount, suspended in 0.7 to 1.5 parts by weight of ethyl acetate saturated with water, and the resulting suspension. allow to stand for 1 to 2 days and separate the precipitate by suction, b) wash the precipitate obtained with 0,07 to 0,15 parts by weight of ethyl acetate saturated with cold water and dry under vacuum: at 30 to 50 ° C, • ♦ • »1 85855 c) this product is dissolved in 30 to 50 parts by weight of dry (anhydrous) ethyl acetate at reflux, treated for 2 hours under reflux with 0.4 parts by weight of activated carbon, filtered and the filtrate is evaporated at 30 to 50 ° C in vacuo to about 1/12 part the amount of solvent used for dissolution, d) 0.5 to 0.8 parts by weight of ethyl acetate saturated with water is added to the concentrate, the precipitated silibinin is filtered off after 5-10 hours and e) silibinin is suspended in 0.9 to 1.8 parts by weight of technical ethyl acetate, filtered again, pre-dried in vacuo at 30-50 ° C, the pre-dried product is ground and re-dried at 30-50 ° C in vacuo. Process according to Claim 1, characterized in that a) one part by weight of a brownish powder is suspended in 0.9 parts by weight of ethyl acetate saturated with water, allowed to stand for 48 hours at room temperature and the precipitate obtained is filtered off with suction, b) the precipitate is washed with 0.09 with a portion of cold, water-saturated ethyl acetate and dried for 48 hours at 40 ° C under vacuum, c) the product obtained is dissolved in 36 parts by weight of dry ethyl acetate at reflux, heated at reflux for 2 hours. “Together with 0.36 parts by weight of activated carbon, filtered and evaporated at 50 ° C under vacuum to 1/12 of the amount of solvent used for dissolution,: **: (d) 0.6 parts by weight of ethyl acetate saturated with water are added to the concentrate at room temperature. , allow to stand for 12 hours at room temperature and separate the precipitated product by filtration 11a, e) suspend this product twice in each case in 1.8 parts by weight of technical grade ethyl acetate and filter, pre-dry for 24 hours under vacuum at 40 ° C, grind and dry for 48 hours under vacuum 40 ° C. 12 85855