CS207858B1 - Macromolecular rentgen-contrasting substance and method of preparation thereof - Google Patents

Description

The invention relates to macromolecular substances of an X-ray absorber.

Substances that are capable of filling these cavities and which strongly absorb X-rays are used to detect cavities in the human body, so that the cavities are shown with sufficient contrast when viewed from the shield or in the images. Therefore, these are also called radiopaque or radio-opaque.

Physical, physiological and toxicological requirements are imposed on the use of the substance.

From a physical point of view, the substance must have a high electron density in unit volume to absorb X-rays sufficiently intensely. This can be achieved by means of high atomic number elements. In general, a radiocontrast agent gives better contrast, the more atoms of high atomic number elements As a result, in the construction of radio-contrast agents, it is sought to use small molecules with high atomic number elements such as barium sulfate, thorium oxides or iodinated organic molecules.

In the latter case, it is utilized that the benzene nucleus can be easily substituted by up to three iodine atoms, which makes it possible to achieve a specific electron density not readily achievable by other means.

From a physiological point of view, the substance should fill the required cavity and remain in the cavity for as long as possible without significant dilution. This is achieved by the use of solid, sparingly soluble substances, such as barium sulphate, which fills the digestive tube, or substances with special affinity, e.g., substances excreted in the gallbladder, kidney into the urine. A special situation arises where the walls of the cavity are permeable to the substance used, and it rapidly diffuses from the cavity. This problem, for example, occurs in lymphography, where the lymphatic pathways have a small dimension (cross-section), so to achieve contrast, it is necessary to create a considerable concentration of radiocontrast substance in the

207 6S8 crystalloids (water-soluble small molecule) are highly permeable and the substance leaks rapidly from it, and at the same time cuts through the body fluid penetrating it * This problem is usually solved by using water-insoluble liquids such as iodinated vegetable oils (Oleum lodatum) or higher esters of fatty acids (Lipiodol) ·

In terms of toxicological requirements, substances must comply with the conditions applicable to the route of administration - orally parenterally - administered preparations, ie «must not be toxic, irritant, cause allergy or other undesirable physiological symptoms.It must not release free iodine and be excluded from the body for some time .

While there is a large selection of suitable preparations in the crystalline field, there is a lack of substances with limited diffusion. Iodized oils are difficult to secrete, forming droplets that persist for a long time and can be introduced into organs where they can cause damage (eg lung ambolization, etc.). Therefore, there is an effort to solve this question by macromolecular (polymer) preparations. For example, Swedish patent No 348 110 of 1966 discloses a group of polymers formed by the 2,4,6-triiodobenzoic acid residues being bonded to polymers via bridges at positions 3 and 5 of the benzene ring by bridges consisting of ether-linked glycerol residues . These polymers are prepared by reacting a bifunctional 2,4,6-triiodobenzoic acid derivative with diepoxides such as bis (2,3-epoxypropyl) ether, 1,2-ethanediol diglycidyl ether, 1,4-butanediol diglycidyl ether or 1,3-glacerol glycidyl ether, optionally with the corresponding balchydrin, chloro-2,3-epoxypropane, 1-bromo-2,3-epoxypropane and the like. Another X-ray contrast agent having a relatively large molecule but not a polymer is described in H.Grj.es and H.Pfeiffer Ger.Offen. 2,141, 803 (1973), which are comprised of two differently substituted triiodinated aniline residues linked by a chain of up to 13 atoms in a row. The process consists in reacting the corresponding iodine-substituted aniline derivatives with aoyl chlorides - dicarboxylic acids.

We have now found that any polymer capable of reacting with aliphatic amines to form a solid bond (hereinafter a reactive polymer) can be converted into a macromolecular X-ray contrast agent by reacting it with a low molecular weight compound containing 1 to 6 iodine atoms in the molecule an aliphatic amino group (X-ray amine).

The subject of the invention is a macromolecular X-ray contrast agent, characterized in that the polymer backbone consisting of aspartic acid residues bound to each other by an amidiol bond or polymerized acrylic or methacrylic acid residues or a natural polymer selected from the group consisting of dextran and hydroxyethyl starch bears amidioc side chains bound X-ray contrast amine of formula I

Wherein A is hydrogen, amino-, acylamino-, aminoalkyl-aminohydroxyalkyl- or acylaminoalkyl, and wherein all alkyls have 1 to 4 carbon atoms and the acyls are a lower mono- or dicarboxylic acid or 06-amino acids containing 1 to 6 carbons , Substituent B has one of the structures listed for Substituent A, both of which cannot be simultaneously hydrogen or a terminal aliphatic amine group, Substituent C is hydrogen, carboxyl or carboxyalkyl wherein the alkyl contains 1 to 6 carbons and in nature that no other substituent is terminated with an aliphatic amino group, residue C is terminated with an amide of formula II instead of a carboxyl group

- CONH / CHg) _n NHg, (II), where η = 1 to 6.

The present invention also provides a macromoljecular X-ray contrast agent, characterized in that aspartic acid residues linked to the backbone formed by polyamido-thioic acid residues, or

207,058 polymerized acrylic or methacrylic acid residues are bound in the side chains by an X-ray contrast amine which is used as a crystalloid X-ray contrast agent or is an intermediate in the production of such materials.

The macromolecular X-ray contrast agent of the invention is prepared by adding to the reactive polymer solution an X-ray contrast amine or its hydrochloride with an equivalent amount of a hydrogen chloride binding agent and reacting and replacing the unreacted reactive groups with a physiologically acceptable aliphatic amine or hydrolyzing in alkaline aqueous solution.

Further, the invention can be carried out by using as reactive polymer polysuccinimide dissolved in dimethylformamide (DM DM) or dimethylsulfoxide (DMSO), to which an X-ray contrast amine or its hydrochloride with an equivalent amount of hydrogen chloride binding agent is added at room temperature and stirring, preferably triethylamine, allowed to react for 1 to 72 hours and unreacted sucoinimide rings are either cleaved by hydrolysis in an alkaline aqueous solution or substituted with a physiologically acceptable aliphatic amine.

The process according to the invention can be carried out by using a polymer or copolymer of reactive esters of acrylic or methacrylic acid selected from the group consisting of esters of these acids with 1-hydroxybenztriazole, N-hydroxysuccinimide, 2,4,5-trichlorophenol, nitrophenol, 2,4-dinitrophenol, optionally copolymerized with physiologically acceptable inert comonomers selected from vinylpyrrolidone, acrylamide, methacrylamide, mono- or dihydroxyalkyl acrylamide or methacrylamide, wherein the alkyl contains one to four carbon atoms.

In addition, the reactive polymer is a natural polymer activated for coupling with amines.

It is furthermore possible according to the invention to use polymeric acyl chlorides, acylanhydrides or polymers containing oxirane groups as reactive polymer for the reaction with X-ray amine.

Polypeptide skeleton polymers can be obtained, for example, by reacting an X-ray contrast amine with poles (sucoinimide) (P.Neri, G.Antoni, F. Benvenuti, P. Coola and G. Gazzei, J. Med. Chem. 16, 893 (1973)) by the method described for aliphatic amines (J.

Vlasak, F.Rypacek, J.Drobnik and V.Saudek, J.Polymer Sci., In print), preferably substituting only a portion of the reactive succinimide rings and hydrolyzing the residue to obtain high water solubility or physiologically substituted. harmless functional groups affecting the polymer oasis in the body.

Polymer-based skeleton polymers can, for example, retain a pentanecantrastamine amine with polymers and copolymers of reactive acrylic acid and methaphthylic acid derivatives, or other polymerizable and reactive mixtures, such as acid ethers, acid anhydrides, polymers of isomers, isocyanates, polymers and isocyanates, In Rothrat (H.-G.Batz, G. Tranzmann and Revfingen, Makromol. Chem. 172, 27 (1973)).

In both cases, only a portion of the reactive groups on the polymer are preferably occupied by an X-ray amine, and the residue is either hydrolysed to form hydrophilic groups, most often carboxyls, which provide the product with sufficient water solubility or react with the aliphatic amine selected toxicologically and provide the product with the properties required for the intended application. Such a physiologically acceptable amine is, for example, 2-aminoethanol which introduces a physiologically inert hydrophilic hydroxyethyl group into the polymer, 2-hydroxypropylamine, or one of the natural amino acids, for example lysine, or another amino acid, for example alanine which introduces a carboxyethyl group or arginine , which is bound to the amino group introduces a positively charged guanidine group into the molecule. The charged groups are converted into salts in the final product as is customary in existing preparations, for example, the carboxyls are neutralized with meglumine (1-desoxy-1-methylamino-D-sorbit) or other substances authorized by the pharmacopoeia for the particular mode of application.

207 8S8

X-ray amine ee usually fails to occupy all monomeric units for various reasons. However, this is not a problem, on the contrary, the remaining units can be additionally occupied to control, for example, solubility or distribution in the body. Table 1 summarizes the data showing what mass iodine contents can theoretically be achieved by varying the monomer occupancy and converting the remaining units by hydrolysis to carboxyls or by physiologically acceptable amine substitution. since it contains such a neutralizing substance, most often meglumine (mol, weight 195). However, this applies to all preparations including the acid-based crystalline used.

An advantage of the process of preparing the X-ray macromolecular substance of the invention is that the photon absorbing property of the X-rays can be introduced into any polymer that can be prepared in the form of reacting with aliphatic amines to form a solid bond. It provides a method for preparing a wide choice of suitable polymer and its other functional groups. This differs from that of the subject of the Swedish patent cited above. This polymer has to be reconstituted and does not offer many possibilities for variation.

A further advantage of the process according to the invention is that the X-ray contrast amine can be prepared from existing industrial grade contrast media or some of the intermediates present in its manufacture (see, for example, the synthesis scheme of E.Pelder, D.Pitré and L.Pumagalli, Helv.Chim Aota 48, 259 (1965)) by conventional, undemanding procedures.

Example 1

The 3-aminobenzoic acid ethyl ester was purified by vacuum distillation, and to the product, 7.6 g of ammonium chloride and 460 ml of 1,2-diaminoethane were added, and refluxed under a nitrogen atmosphere at 135 ° C for 7 hours, excluding moisture ingress. was removed by re-distillation with water · The product was purified by carboraffin in the presence of ethanol. To the ethanol solution was added a solution of hydrogen chloride in ethyl ether, the precipitate formed was 3-aminobenzoic acid-aminoethylamide dihydrochloride · The product was iodinated according to PLWeitl, M.Sovak, and JH

Lang (J. Med. Chem. 19, 1359 (1976). The resulting product was 2, 4, 6-triiodo-3-aminobenzoic acid hydrochloride-aminoethylamide.

Example 2

3.5 g of 15,000 average molecular weight polysukoinimide prepared according to P.Neri, G.antoni, P. Benvenuti, P.Cola and G. Gazzei, J. Med. Chem., 16, 893 (1973), were dissolved in 25 ml of DMF and 15.7 g of Hydrochloride were added at room temperature

- 2,4,6-triiodo-3-aminobenzoic acid aminoethylamide dissolved in 75 ml DMP and 6.6 g triethylamine in 25 ml DM? · Allow to react at 45 ° C for 72 hours with stirring. Then 850 ml of a IfagCO3 solution containing 130 g of anhydrous sodium carbonate are added and left to stir for 48 hours with occasional stirring at room temperature. It is then poured into a pallierizer and dialyzed against running distilled water. Removal and low molecular weight substances can be accomplished, for example, by gel filtration. The preparation was lyophilized and analyzed and, according to the result of the analysis, the residue was adjusted to the desired conoentraoi, neutralized with meglumine (1-desoxy-1-methylamino-D-sorbit) and sterilized by filtration. A part was lyophilized again, part sealed into ampoules. The defective film contained 42% iodine.

Example 3

2,4,6-triiodo-3-aminobenzoic acid amineethylamide (product of Example 1) was coupled to the polysukoimide as in Example 2, and after reaction was added to DM? of the solution was added 6.4 g of succinic anhydride and allowed to react at room temperature for 24 hours. The next procedure, hydrolysis with sodium carbonate, etc., was identical to Example 2. Lyophilized substance contained

207 8S8 produced 37.5% iodine.

Example 4

Following the same procedure as in Example 2, 2,4,6-tri-iodo-3-aminobenzoic acid amtooethylamide was coupled to polysuccinimide and after reaction to DME ¹ solution 7 g of 2-aminoethanol were added and allowed to react at room temperature for 24 hours. proceeded directly to dialysis, lyophilization, neutralization and further processing as in Example 2. The lyophilized substance contained 38.3% iodine.

Example 5

37.5 g of iopanoic acid (i.e. - (3-amino-2,4,6-triiodobenzyl) butyric acid) were dissolved in 500 ml of pyridine and N-phthaloyl-2-hydrochloride was added in portions at room temperature with constant stirring. aminopropionyl chloride up to the total amount

11.5 g} · further proceed according to J. Hebky, M. Karasek, J.Kejha and B.Eirst, Collection Czechoslov.Chem.Commun. 29, 2814 (1964). Product isolated as' £ 3 (2-aminopropionylamino) -2,4,6-triiodobenzyl] butyric acid hydrochloride

CH 2 CH 2 CH. COOH

HH.CO.CHgCHgNHg. HCl and used to bind to the polysuccinimide by the method described in Example 2. The lyophilized preparation had an iodine content of 28 # ·

EXAMPLE 6 g 3-Aminomethyl-5-amino-2,4,6-triiodobenzoic acid hydrochloride (Intermediate XI from E.Pelder, D.Pitra and L.Pumagali, Helv.Chim.Acta 48, 259 (1965)) was coupled to polysuccinimide as described in Example 1. The resulting product after lyophilization contained 35.2% iodine.

Example 7

33.8 g of 2,4,6-triiodo-3-aminobenzoic acid, which was purified according to U.S. Pat. No. 132704, was substituted on the 3-amino group by the method described in Example 5. The product was isolated as acid hydrochloride 3 ( 2-aminopropionylamino) 2,4,6-triiodobenzoic acid

COOH

J

0¾ CH ₂ NHg. HCl and was used to bind to the polysuccinimide as in Example 1 in an amount of 16.5 g. The other procedure was analogous.

Example 8 g of 18,000 average molecular weight polysuccinimidomethacylate prepared according to H.-G.Batz, G.Pranzmann and H.Ringsdorf, Makromol.Chem. 172, 27 (1973), was dissolved in 50 ml of DMP and 8.6 g 2,4,6-triiodo-3-aminobenzoic acid hydro-chloride-aminoethyl amide in 150 ml DM3 was added at 5-10 ° C. and 1.5 g of triethylamine. After 2 hours succinic anhydride (3 g) was added and the temperature raised to 45 ° C. The reaction was allowed to proceed for 24 hours and further processed as in Example 2. The lyophilized product contained 42.5% iodine.

0 7 8 N 8

Example 9

5.8 g of soluble starch (Lachema) was suspended in 10 ml of water and 10 ml of pyridine and dissolved by heating. Then 200 ml of pyridine was added and distilled until the volume fell to half. The solution was cooled to -10 ° C with 0.1 mole of phosgene dissolved in toluene. Allowed to warm to room temperature and stirred overnight. Then cooled with ice and added 30 g of methyl 3 (2-aminopropionylamino) -2,4,6-triiodobenzoic acid ester (see Example 7), allowed to warm to room temperature after 2 hours, stirred over night and 5 hours at 50 ° C. The product was precipitated with ethanol, washed first with ethanol 96%, then 40% until the reaction to chloride disappeared, and heated in sodium bicarbonate solution to 45 ° C for 24 hours · The product contained 22% iodine in dry matter ·

Example 10 g of a microporous spherical copolymer of glycidyl methacrylate ethylene dimethacrylate (P.Sveo et al., Angew. Makromol.Chem. 63, 23 (1977) was suspended in 5 ml of dimethylformamide-water 95%. of Example 1 and the equivalent (0.48 g) of triethylamine * heated at 60 ° 0 for 72 hours · The product was washed with DM 2 then water containing 18% iodine in dry matter ·

Example 11

The preparation obtained according to Example 2, treated with meglumine to pH 6.9 and undiluted to an iodine content of 16%, was not sprayed into the lymphatic vessel on the left hind leg of the dog (16 kg) at 1 ml and on the right leg at 3 µm. . In both cases it was possible to observe contrasting depiction of the lymphatic system, the passage of the substance through the popliteal lymph node and further to the paraaortic lymph node from both the shield and the images. Contrast reached maximum after about 30 minutes after injection * In 3 hours the substance was no longer visible in the lymphatic pathways, only a slight shade remained in the lymph nodes, which disappeared by the next day ·

Claims (3)

SCOPE 1. A macromolecular X-ray contrast agent whose polymer backbone consists of an aspartic acid residue bound by an amdl bond or a polymerized acrylic or methacrylic acid residue or a natural polymer selected from the group consisting of dextran and hydroxyethyl starch »carries an amine bonded amine bonded X-ray contrast of formula I J AND J is aoylamino-, aminoalkyl-, aminohydroxyalkyl- somewhere substituent A is hydrogen, amino- or acylaminoalkyl, and wherein all alkyls contain 1 to 4 carbon atoms and aoyls are lower mono- or dicarboxylic acid residues or amino acids containing 1 to 6 carbons, substituent B has one of the structures listed for substituent A, both of which cannot be simultaneously hydrogen or a terminal aliphatic amine group, substituent C is hydrogen, carboxyl or carboxyalkyl wherein the alkyl contains 1 to 6 carbons and when no other substituent is terminated an aliphatic amino group, the residue O is terminated with an amide of formula II '- COEH (CHg) _n NHg, (II), where n 1 to 6, instead of carboxyl. 2. Method of production of macromolecules! X-ray contrast agents according to Claim 1, characterized in that to a solution of a reactive polymer selected from the group consisting of a polymer or copolymers of reactive esters of acrylic or methacrylic acid selected from the group comprising esters of these acids with 1-hydroxybenztriazole, N-hydroxysuccinimide, 2,4,5 trichlorophenol, 4-nitrophenol, 2,4-dinitrophenol, optionally copolymerized and physiologically acceptable inert comonomers selected from the group consisting of vinyl pyrrolidone, acrylamide, methacrylamide, mono- or dihydroxyalkylacrylamide or methacrylamide; methacryloyl chlorides, acrylate hydride or methacrylanhydride, polymers based on glycidyl methacrylate, natural poles of mer mer selected from the group consisting of dextran and hydroxyethyl starch activated for amine bonding, are added in an amount of 1 to 2 moles per mole of reactive polymer group eru X-ray contrast amine or its hydrochloride with an equivalent amount of hydrogen chloride binding agent or reagent and reacted with thorough stirring at 0 to 60 ° 0 and unreacted reactive groups are substituted with physiologically acceptable aliphatic amine or hydrolyzed in alkaline aqueous solution, whereupon the product rid of low molecular weight substances by membrane ultrafiltration or dialysis · 3. A process for the preparation of a macromolecular X-ray contrast agent according to claim 1, characterized in that the reactive polymer is polysuccinimide dissolved in dimethylformamide or dlmethylsulfoxide, to which X-ray contrast amine or its hydrochloride with an equivalent amount of hydrogen chloride binding agent is added. preferably triethylamine, allowed to react for 1 to 72 hours and unreacted succinimide rings are either cleaved by hydrolysis in an alkaline aqueous solution or substituted with a physiologically acceptable aliphatic amine, and then further processed as in 2,