Patent Application
20250161526
The present invention relates to an embolic agent and a kit for vascular embolization.
Priority is claimed on Japanese Patent Application No. 2022-030098, filed Feb. 28, 2022, the content of which is incorporated herein by reference.
Embolization involves partial or complete occlusion of a blood vessel, restricting the flow of blood through the vessel. Therapeutic embolization is used to treat a variety of conditions, such as cerebral and peripheral aneurysms, arteriovenous malformations, uterine fibroids, and to reduce or block blood flow to tumors. Embolization can be achieved by a variety of means, including the use of polymer microspheres, metal coils, metal or polymer plugs, and liquid embolic materials. Of these means, an appropriate means can be selected based on the size of the blood vessel to be occluded, the desired duration of occlusion, or the type of disease or condition to be treated.
Examples of the liquid embolic materials that have been conventionally used include N-butyl cyanoacrylate (NBCA; trade name: “TRUFILL (registered trademark)” manufactured by Codman & Shurtleff, Inc., etc.) and ethylene vinyl alcohol copolymer (EVOH; trade name: “Onyx (registered trademark)” manufactured by ev3 Endovascular, Inc., etc.) (see, for example, Patent Document 1, etc.). The main mechanism of action of NBCA is a polymerization reaction with blood, and that of EVOH is precipitation in blood and coagulation action to embolize blood vessels.
As an alternative, the inventors have developed a cationic π polymer (poly(cation-adj-π)) having an adjacent cationic functional group-aromatic group arrangement (see, for example, Non-Patent Document 1, etc.). It has been reported that the cationic 7 polymer has strong yet reversible adhesion to a negatively charged surface in an aqueous solution (0.7 M NaCl aqueous solution) containing the same amount of salt as seawater.
However, with the conventional liquid embolic materials such as NBCA and EVOH, the embolic material may adhere to the tip of the catheter, and when the catheter is withdrawn, there is a risk of damaging the inner wall of the blood vessel or the catheter insertion site, causing bleeding. EVOH requires the use of dimethyl sulfoxide (DMSO) as a solvent, and the approval review report (new medical device) (Non-Patent Document 2) issued by the Pharmaceuticals and Medical Devices Agency (PMDA) describes the possibility of local nerve damage and damage to the blood vessel wall caused by DMSO for commercially available EVOH products. For this reason, only an amount of EVOH that can be dissolved in an amount of DMSO that does not cause neurotoxicity can be administered, and it may be necessary to administer it two or more times. Furthermore, EVOH requires the use of a special catheter and syringe suitable for using DMSO in order to administer it, which places a heavy burden on the patient in terms of cost.
The present invention has been made in consideration of the above-described circumstances, and provides an embolic agent that has vascular embolization properties equivalent to those of conventional embolic agents, while being easy to inject with a syringe and having excellent safety and stability in the living body, and a kit for vascular embolization including the embolic agent.
As a result of intensive research into achieving the above-mentioned object, the inventors have discovered that a copolymer having, at least in part, a structure consisting of an alternating arrangement of cationic functional group-containing monomer units and aromatic group-containing monomer units has good injectability using a syringe and generates almost no resistance when a catheter is withdrawn from within a blood vessel, and that administration of the copolymer into a blood vessel forms a safe and stable blood clot-like gel mass through electrostatic interaction with blood components, thereby completing the present invention.
That is, the present invention includes the following aspects.
(in general formula (I), R11 and R12 are hydrogen atoms or alkyl groups having 1 to 20 carbon atoms which may have a substituent, and satisfy a relational formula: R11=R12; Y11 and Y12 are each independently a single bond, or an alkylene group having 1 to 20 carbon atoms which may contain one or more selected from the group consisting of a hydroxyl group, an ester bond, an ether bond, a sulfide group, a carbonyl group, an amide bond and a phosphodiester bond; Ar11 is an aromatic hydrocarbon group having 6 to 16 carbon atoms which may have a substituent; X11 is an ammonium group or an amino group; and n11 is an integer of 10 to 1,000.)
(in general formula (I-1), R111 and R112 are hydrogen atoms or methyl groups, and satisfy a relational formula: R111=R112; Y111 and Y112 are each independently an alkylene group having 1 to 20 carbon atoms which may contain one or more selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group and a phosphodiester bond; Ar111 is a phenyl group which may have a substituent; X111 is a quaternary ammonium group; and n111 is an integer of 10 to 1,000.)
According to the above-described embodiment of the embolic agent, it is possible to provide an embolic agent that has vascular embolization properties equivalent to those of conventional embolic agents, while being easy to inject with a syringe and excellent in safety and stability in the living body.
The embolic agent of the present embodiment contains as an active ingredient a copolymer of a cationic functional group-containing monomer and an aromatic group-containing monomer, the copolymer having at least a part thereof a structure represented by the following general formula (I) (hereinafter, sometimes referred to as “structure (I)”).
(In general formula (I), R11 and R12 are hydrogen atoms or alkyl groups having 1 to 20 carbon atoms which may have a substituent, and satisfy a relational formula: R11=R12. Y11 and Y12 are each independently a single bond, or an alkylene group having 1 to 20 carbon atoms which may contain one or more selected from the group consisting of a hydroxyl group, an ester bond, an ether bond, a sulfide group, a carbonyl group, an amide bond, and a phosphodiester bond. Ar11 is an aromatic hydrocarbon group having 6 to 16 carbon atoms which may have a substituent. X11 is an ammonium group or an amino group. n11 is an integer of 10 to 1,000. The wavy line represents a bonding site.)
The embolic agent of the present embodiment, having the above-mentioned configuration, has vascular embolization properties equivalent to those of conventional embolic agents, while being excellent in injectability with a syringe, and in safety and stability in the living body.
In this specification, “containing as an active ingredient” means containing a therapeutically effective amount of the copolymer. In this specification, “therapeutically effective amount” means an amount of the copolymer, or a combination of the copolymer and one or more active agents, that induces the biological or medical effect or response desired by a physician, clinician, veterinarian, researcher, or other appropriate professional when administered according to a desired treatment regimen. A preferred therapeutically effective amount is an amount that improves the symptoms of a disease requiring intravascular embolization. Specific examples of such diseases are described below.
The copolymer is formed by copolymerizing a cationic functional group-containing monomer and an aromatic group-containing monomer, and has the above-described structure (I) at least in part. The structure (I) is consisting of an arrangement in which the cationic functional group-containing monomer and the aromatic group-containing monomer are alternately arranged. Alternatively, the structure (I) can be said to be a structure in which units each consisting of one molecule of the cationic functional group-containing monomer and one molecule of the aromatic group-containing monomer are continuous.
The mechanism of blood coagulation by the copolymer is that negatively charged blood components (red blood cells, white blood cells, platelets and the like) or proteins in the blood bind to the cationic functional groups in the copolymer via electrostatic interaction to form a blood clot-like gel mass (hereinafter referred to as blood gel) containing blood, thereby embolizing the blood vessel. It is presumed that the aromatic groups in the blood gel form a hydrophobic field, stabilizing the blood gel in the body. Note that the above-described mechanism is merely an example for the embolic agent of the present embodiment, and the present invention is not limited to the above-described mechanism as long as it can exert the effect.
[R11 and R12]
R11 and R12 are hydrogen atoms or alkyl groups having 1 to 20 carbon atoms which may have a substituent. In addition, a formula: R11=R12 is satisfied. In the present invention and the present specification, the “alkyl group having 1 to 20 carbon atoms which may have a substituent” includes both an “alkyl group having 1 to 20 carbon atoms which has no substituent” and an “alkyl group having 1 to 20 carbon atoms which has a substituent”. By using a cationic functional group-containing monomer and an aromatic group-containing monomer which satisfy the formula, a copolymer having the structure (I) at least in a part thereof can be obtained.
The “alkyl group having 1 to 20 carbon atoms” for R11 and R12 is preferably a chain-like group. The chain alkyl group may be linear or branched. The chain alkyl group is preferably a group having 1 to 6 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group and the like.
Examples of the substituent on R11 and R12 include halogen atoms and the like. Examples of the halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like. The number of the substituents possessed by R11 and R12 may be 1 or more, preferably 1 or more and 5 or less, and more preferably 1 or more and 3 or less.
Among these, R11 and R12 are preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, more preferably a hydrogen atom, a methyl group, or an ethyl group, and even more preferably a hydrogen atom or an ethyl group.
[Y11 and Y12]
Y11 and Y12 are each independently a single bond, or an alkylene group having 1 to 20 carbon atoms which may contain one or more selected from the group consisting of a hydroxyl group, an ester bond, an ether bond, a sulfide group, a carbonyl group, an amide bond, and a phosphodiester bond. In the present invention and the present specification, the “alkylene group having 1 to 20 carbon atoms which may contain one or more selected from the group consisting of a hydroxyl group, an ester bond, an ether bond, a sulfide group, a carbonyl group, an amide bond, and a phosphodiester bond” includes both an “alkylene group having 1 to 20 carbon atoms which does not contain one or more selected from the group consisting of a hydroxyl group, an ester bond, an ether bond, a sulfide group, a carbonyl group, an amide bond, and a phosphodiester bond” and a “single bond or an alkylene group having 1 to 20 carbon atoms which contains one or more selected from the group consisting of a hydroxyl group, an ester bond, an ether bond, a sulfide group, a carbonyl group, an amide bond, and a phosphodiester bond”. The “alkylene group having 1 to 20 carbon atoms which contains one or more selected from the group consisting of a hydroxyl group, an ester bond, an ether bond, a sulfide group, a carbonyl group, an amide bond, and a phosphodiester bond” is preferably an alkylene group having 1 to 20 carbon atoms which contains one to three selected from the group consisting of a hydroxyl group, an ester bond, an ether bond, a sulfide group, a carbonyl group, an amide bond, and a phosphodiester bond.
Examples of the alkylene group having 1 to 20 carbon atoms for Y11 and Y12 include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, an undecylene group, a dodecylene group, a tetradecylene group, a hexadecylene group, an octadecylene group, a nonadecylene group, an icosylene group and the like. Among these, the alkylene group for Y11 and Y12 is preferably a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, or a decylene group, more preferably a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, or an octylene group, and even more preferably a methylene group, an ethylene group, a propylene group, or a butylene group.
Among these, Y111 and Y12 are preferably an alkylene group having 1 to 10 carbon atoms, which may contain one or more, preferably one to three, selected from the group consisting of a hydroxyl group, an ester bond, an ether bond, a sulfide group, and a phosphodiester bond.
In addition, in view of the ease of interaction between the cationic functional group and the aromatic group, it is preferable that the lengths of the linkers Y11 and Y12 are approximately the same so that the distance between these functional groups is short, and it is more preferable that the absolute value of the difference between the number of carbon atoms of Y11 and the number of carbon atoms of Y12 is 0 or more and 3 or less.
More specifically, the preferred examples of Y11 and Y12 include groups represented by the following general formulas (Iy-1) to (Iy-7) (hereinafter, sometimes referred to as “group (Iy-1)” or the like). Note that groups (Iy-1) to (Iy-7) are merely examples of preferred Y11 and Y12, and preferred Y11 and Y12 are not limited thereto. In groups (Iy-1) to (Iy-7), the wavy line on the left side represents a bonding site with the carbon atom to which R111 or R112 is bonded, and the wavy line on the right side represents a bonding site with X11 or Ar11.
Ar11 is an aromatic hydrocarbon group having 6 to 16 carbon atoms which may have a substituent. Examples of the aromatic hydrocarbon group having 6 to 16 carbon atoms for Ar11 include a phenyl group, a naphthyl group, an anthracenyl group and the like. In the present invention and this specification, the “aromatic hydrocarbon group having 6 to 16 carbon atoms which may have a substituent” includes both an “aromatic hydrocarbon group having 6 to 16 carbon atoms which does not have a substituent” and an “aromatic hydrocarbon group having 6 to 16 carbon atoms which has a substituent”.
Examples of the substituent on Ar11 include an alkyl group, a halogen atom and the like. Examples of the alkyl group and the halogen atom include the same as those exemplified above for R11 and R12. When Ar11 is an “aromatic hydrocarbon group having 6 to 16 carbon atoms which has a substituent”, the number of the substituents in the aromatic hydrocarbon group is preferably 1 to 5, and more preferably 1 to 3.
Among these, Ar11 is preferably a phenyl group which may have a substituent, and more preferably a phenyl group which does not have a substituent or a phenyl group which has 1 to 3 substituents.
X11 is a cationic functional group, and is an ammonium group or an amino group. Among these, X11 is preferably an ammonium group, and more preferably a quaternary ammonium group.
Preferred examples of the quaternary ammonium group include groups represented by the following general formulas (Ix-1) to (Ix-7) (hereinafter, sometimes referred to as “group (Ix-1)” or the like). Note that groups (Ix-1) to (Ix-7) are merely examples of the preferred quaternary ammonium groups, and the preferred quaternary ammonium groups are not limited thereto. The wavy line represents a bonding site with Y11.
The quaternary ammonium group is usually supplied in an ionically bonded state with a suitable anion. Examples of the anions that can be ionically bonded with the quanternary ammonium group include halogen ions such as a chloride ion, a bromide ion, a fluoride ion, an iodide ion or the like, a hydroxide ion, a sulfate ion, an acetate ion and the like, among which a chloride ion is preferred.
[n11]
n11 is an integer of 10 or more and 1,000 or less, preferably an integer of 30 or more and 1,000 or less, more preferably an integer of 50 or more and 1,000 or less, even more preferably an integer of 70 or more and 1,000 or less, and particularly preferably an integer of 100 or more and 1,000 or less.
In the structure (I), the wavy line on the cationic functional group-containing monomer unit side and the wavy line on the aromatic group-containing monomer unit side each independently represent a bonding site with any one of the following:
The copolymer may have one or more structures (I). That is, when the cationic functional group-containing monomer unit is A and the aromatic group-containing monomer unit is B, the copolymer may have, for example, the following sequence. The following sequence is merely an example of the sequence of the copolymer, and the sequence of the copolymer is not limited to the following. In the following sequence, H represents a hydrogen atom, M represents a unit derived from a polymerization initiator, n11 is the same as n11 described above, and n12 and n13 are each independently an integer of 1 or more.
The preferred examples of the structure (I) include a structure represented by the following general formula (I-1) (hereinafter, sometimes referred to as “structure (I-1)”). Note that the structure (I-1) is merely an example of the preferred structure (I), and the preferred structure (I) is not limited thereto.
(In general formula (I-1), R111 and R112 are hydrogen atoms or methyl groups, and satisfy a relational formula: R111=R112. Y111 and Y112 are each independently an alkylene group having 1 to 20 carbon atoms which may contain one or more selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond. Ar111 is a phenyl group which may have a substituent. X111 is a quaternary ammonium group. n111 is an integer of 10 to 1,000. The wavy line represents a bonding site.)
[R111 and R112]
R111 and R112 are a hydrogen atom or a methyl group and satisfy a relational formula: R111=R112.
[Y111 and Y112]
Y111 and Y112 are each independently an alkylene group having 1 to 20 carbon atoms which may contain one or more selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond. In the present invention and the present specification, an “alkylene group having 1 to 20 carbon atoms which may contain one or more selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond” includes both an “alkylene group having 1 to 20 carbon atoms which does not contain one or more selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond” and an “alkylene group having 1 to 20 carbon atoms which contains one or more selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond”. The “alkylene group having 1 to 20 carbon atoms which contains one or more selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond” is preferably an alkylene group having 1 to 20 carbon atoms which contains one to three selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond.
Examples of the alkylene group having 1 to 20 carbon atoms for Y111 and Y112 include the same groups as those exemplified above for Y11 and Y12.
Among these, Y111 and Y112 are preferably an alkylene group having 1 to 10 carbon atoms which may contain one or more, preferably one to three, selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond; more preferably an alkylene group having 1 to 6 carbon atoms which may contain one or more, preferably one to three, selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond; even more preferably an alkylene group having 1 to 4 carbon atoms which may contain one or more selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond; and still even more preferably an alkylene group having 1 to 4 carbon atoms which does not contain one or more selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond, or an alkylene group having 1 to 4 carbon atoms which contains one to three selected from the group consisting of a hydroxyl group, an ether bond, a sulfide group, and a phosphodiester bond.
Ar111 is a phenyl group which may have a substituent. Examples of the substituent include the same as those exemplified above for Ar11. Ar111 is preferably a phenyl group which does not have a substituent or a phenyl group which has 1 to 3 substituents.
X111 is a quaternary ammonium group. Examples of the quaternary ammonium group include the same groups as those exemplified above for X11.
[n111]
n111 is an integer of 10 or more and 1,000 or less, preferably an integer of 30 or more and 1,000 or less, more preferably an integer of 50 or more and 1,000 or less, even more preferably an integer of 70 or more and 1,000 or less, and particularly preferably an integer of 100 or more and 1,000 or less.
In the structure (I-1), the wavy line on the cationic functional group-containing monomer unit side and the wavy line on the aromatic group-containing monomer unit side are the same as the wavy line on the cationic functional group-containing monomer unit side and the wavy line on the aromatic group-containing monomer unit side in the structure (I), respectively.
The preferred examples of the structure (I-1) include structures represented by the following general formulas (I-1-1) to (I-1-6). Note that the structures (I-1-1) to (I-1-6) are merely examples of the preferred structure (I-1), and the preferred structure (I-1) is not limited thereto.
(In the above general formula, n112 is the same as n111 described above.)
The cationic functional group-containing monomer may be any monomer having a cationic functional group and a polymerizable functional group, and examples thereof include a compound represented by the following general formula (Ia) (hereinafter, sometimes referred to as “compound (Ia)”):
(In formula (Ia), Ra11, Ya11 and Xa11 are the same as R11, Y11, and X11, respectively, described above.)
The preferred examples of compound (Ia) include a compound represented by the following general formula (Ia-1) (hereinafter, may be referred to as “compound (Ia-1)”). Compound (Ia-1) is a monomer having a (meth)acrylic acid ester skeleton. Note that compound (Ia-1) is merely an example of the preferred compound (Ia), and the preferred compound (Ia) is not limited thereto.
(In formula (Ia-1), Ra111, Ya111, and Xa111 are the same as R111, Y111, and X111, respectively, described above.)
The preferred examples of compound (Ia-1) include compounds represented by the following general formulas (Ia-1-1) to (Ia-1-4) (hereinafter, sometimes referred to as “compound (Ia-1-1) and the like”). Compounds (Ia-1-1) to (Ia-1-4) are monomers having a (meth)acrylic acid ester skeleton. Note that compounds (Ia-1-1) to (Ia-1-4) are merely examples of the preferred compound (Ia-1), and the preferred compound (Ia-1) is not limited thereto.
Compound (Ia-1-1) is 2-(acryloyloxy)ethyl trimethylammonium.
Compound (Ia-1-2) is 2-(acryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate.
Compound (Ia-1-3) is 2-(metacryloxy)ethyl trimethylammonium.
Compound (Ia-1-4) is 2-(metacryloxy)ethyl 2-(trimethylammonio)ethyl phosphate.
The aromatic group-containing monomer may be any monomer having an aromatic group and a polymerizable functional group, and examples thereof include a compound represented by the following general formula (Ib) (hereinafter, sometimes referred to as “compound (Ib)”).
(In formula (Ib), Rb11, Yb11, and Arb11 are the same as R12, Y12, and Ar11, respectively, described above.)
The preferred examples of compound (Ib) include a compound represented by the following general formula (Ib-1) (hereinafter, may be referred to as “compound (Ib-1)”). Compound (Ib-1) is a monomer having a (meth)acrylic acid ester skeleton. Note that compound (Ib-1) is merely an example of preferred compound (Ib), and the preferred compound (Ib) is not limited thereto.
(In general formula (Ib-1), Rb111, Yb111 and Arb111 are the same as R112, Y112 and Ar111, respectively, described above.)
The preferred examples of compound (Ib-1) include compounds represented by the following general formulas (Ib-1-1) to (Ib-1-10) (hereinafter, sometimes referred to as “compound (Ib-1-1) and the like”). Compounds (Ib-1-1) to (Ib-1-10) are monomers having a (meth)acrylic acid ester skeleton. Compounds (Ib-1-1) to (Ib-1-10) are merely examples of the preferred compound (Ib-1), and the preferred compound (Ib-1) is not limited thereto.
Compound (Ib-1-1) is benzyl acrylate.
Compound (Ib-1-2) is 2-phenoxyethyl acrylate (PEA).
Compound (Ib-1-3) is 2-(2-phenoxyethoxy)ethyl acrylate.
Compound (Ib-1-4) is 2-(phenylsulfanyl) ethyl acrylate.
Compound (Ib-1-5) is 2-hydroxy-3-phenoxypropyl acrylate.
Compound (Ib-1-6) is benzyl methacrylate.
Compound (Ib-1-7) is 2-phenoxyethyl methacrylate.
Compound (Ib-1-8) is 2-(2-phenoxyethoxy)ethyl methacrylate.
Compound (Ib-1-9) is 2-(phenylsulfanyl)ethyl methacrylate.
Compound (Ib-1-10) is 2-hydroxy-3-phenoxypropyl methacrylate.
The copolymer may have units derived from other monomers in addition to the units derived from the cationic functional group-containing monomer and the aromatic group-containing monomer.
The other monomers may be any monomers that do not have a cationic functional group or an aromatic group, but have a polymerizable functional group that can be polymerized with the cationic functional group-containing monomer and the aromatic group-containing monomer. Examples of such other monomers include the following. These may be used alone or in combination of two or more.
In the copolymer, the molar ratio of units derived from the cationic functional group-containing monomer to units derived from the aromatic group-containing monomer may be 1:10 to 10:1, 1:8 to 8:1, or 1:5 to 5:1, preferably 1:4 to 4:1, more preferably 1:2 to 2:1, even more preferably 1.5:1 to 1:1.5, still even more preferably 1.2:1 to 1:1.2, particularly preferably 1.1:1 to 1:1.1, and most preferably 1:1.
The copolymer can be obtained by mixing the cationic functional group-containing monomer and the aromatic group-containing monomer in a predetermined solvent in the presence of a polymerization initiator to carry out solution polymerization. As the cationic functional group-containing monomer and the aromatic group-containing monomer, those monomers in which R11a in general formula (Ia) and R11b in general formula (Ib) are the same are used.
Furthermore, by mixing a cationic functional group-containing monomer and an aromatic group-containing monomer in a predetermined solvent prior to the polymerization reaction, the cationic functional group-containing monomer units and the aromatic group-containing monomer units are likely to be arranged alternately due to the interaction between the cationic functional group and the aromatic group, thereby making it possible to increase the proportion of the above-described structure (I) in the copolymer.
When other monomers are used in addition to the cationic functional group-containing monomer and the aromatic group-containing monomer, they may be mixed before or after mixing the cationic functional group-containing monomer and aromatic group-containing monomer.
The temperature during the mixing may be, for example, 19° C. or higher and 35° C. or lower.
The molar ratio of the cationic functional group-containing monomer to be used to the aromatic group-containing monomer to be used may be 1:10 to 10:1, 1:8 to 8:1, or 1:5 to 5:1, preferably 1:4 to 4:1, more preferably 1:2 to 2:1, even more preferably 1.5:1 to 1:1.5, still even more preferably 1.2:1 to 1:1.2, particularly preferably 1.1:1 to 1:1.1, and most preferably 1:1.
The amount of the other monomers to be used may be determined within a range that does not prevent the cationic functional group-containing monomer units and the aromatic group-containing monomer units from being arranged alternately. Specifically, the amount of the other monomers to be used may be 50 mol % or less, or 30 mol % or less, preferably 10 mol % or less, more preferably 5 mol % or less, even more preferably 1 mol % or less, and particularly preferably 0 mol %, with respect to the total molar amount of the cationic functional group-containing monomer and the aromatic group-containing monomer.
The polymerization initiator may be any compound that initiates a polymerization reaction by heat or light, and examples thereof include 2-oxoglutaric acid, benzoyl peroxide, azobisisobutyronitrile, potassium persulfate, sodium persulfate and the like.
The amount of the polymerization initiator to be used may be 0.001 mol % or more and 0.100 mol % or less, 0.005 mol % or more and 0.050 mol % or less, or 0.010 mol % or more and 0.030 mol % or less, with respect to the total molar amount of the monomers used in the polymerization reaction.
The organic solvent used in the solution polymerization is preferably dimethyl sulfoxide (DMSO).
The amount of the organic solvent to be used is preferably an amount such that the total concentration of the monomers used in the polymerization reaction is 1 mol/L or more. The upper limit of the total concentration of the monomers in the reaction solution may be set to a level that does not cause the reaction solution to become too viscous, and may be set to, for example, 2 mol/L.
The polymerization reaction is initiated by heating the reaction solution to a temperature of, for example, about 50° C. to 100° C., or by irradiating the reaction solution with light such as UV light.
The polymerization reaction temperature can be appropriately set depending on the types of the monomers and the polymerization initiator to be used, and may be set to, for example, 20° C. or higher and 100° C. or lower.
The polymerization reaction time may be from 1 hour to 12 hours.
After the polymerization reaction, the copolymer may be purified.
The copolymer can be purified by a known method, and if necessary, a post-treatment may be performed to extract the copolymer. Specifically, if necessary, post-treatment operations such as filtration, washing, extraction, pH adjustment, dehydration, and concentration may be performed alone or in combination, and the copolymer can be purified by concentration, reprecipitation, column chromatography or the like.
The structure of the copolymer can be confirmed by known techniques such as nuclear magnetic resonance (NMR) spectroscopy, infrared spectroscopy (IR) or the like.
In order to remove as much of the organic solvent, which is toxic to living organisms, as possible from the obtained copolymer, it is preferable to replace the solvent with water by dialysis or the like.
After purification or solvent replacement of the copolymer, drying may be performed. Examples of the drying methods include ventilation drying, drying in a thermostatic chamber, drying under reduced pressure, hot air circulation drying, freeze drying and the like. Among these, freeze drying is preferred. When the freeze drying is performed, a cryoprotectant may be further included from the viewpoint of more effectively suppressing the increase in particle size of the microparticles formed by the copolymer.
The cryoprotectant is not particularly limited as long as it is known as a “cryoprotectant” or a “lyoprotectant for lyophilization”, and examples thereof include disaccharides, sorbitol, dextran, polyethylene glycol, propylene glycol, glycerin, glycerol, polyvinylpyrrolidone, dimethyl sulfoxide and the like.
The disaccharides are not particularly limited, and examples thereof include sucrose, lactulose, lactose, maltose, trehalose, cellobiose, kojibiose, nigerose, isomaltose, isotrehalose, neotrehalose, sophorose, laminaribiose, gentiobiose, turanose, maltulose, palatinose, gentiobiulose, mannobiose, melibiose, melibiulose, neolactose, galactosucrose, scillabiose, neohesperidose, rutinose, rutinulose, vicianose, xylobiose, primeverose and the like.
The amount of the cryoprotectant to be used is not particularly limited, and can be appropriately determined by those skilled in the art according to known methods.
The copolymer may be in solid, semi-solid or liquid form.
In the case of a solid, examples of the form thereof include powder, granules, tablets and the like. Among these, the solid is preferably a freeze-dried powder.
In the case of a semi-solid, examples of the form thereof include a gel.
In the case of a liquid, examples of the form thereof include an aqueous solution in which the powder is dissolved in water or a suspension in which the powder is suspended.
When the embolic agent of the present embodiment is a liquid, the concentration of the copolymer may be 10 mg/L or more and 100 mg/L or less, preferably 20 mg/L or more and 70 mg/L or less, more preferably 30 mg/L or more and 50 mg/L or less. When the concentration of the copolymer is equal to or more than the lower limit, it is possible to more efficiently form an embolism by interacting with blood. On the other hand, when the concentration is equal to or less than the upper limit, it is possible to more effectively store the embolic agent in a stable state by suppressing the increase in viscosity even when the embolic agent is stored for a long period of time, such as about one month. In addition, as shown in the examples described later, when administered to a living body, the embolic agent has excellent injectability by a syringe or a microcatheter, and can be safely extracted from a blood vessel with almost no resistance.
Examples of the subjects to which the embolic agent of the present embodiment is administered include, but are not limited to, humans, monkeys, dogs, cows, horses, sheep, pigs, rabbits, mice, rats, guinea pigs, hamsters and the like. Among these, mammals are preferred, and humans are particularly preferred.
Administration to the human or animal patient is preferably a local administration to the site where embolization is desired, as the copolymer interacts with the blood to form a gel.
Specific examples of the administration method include methods which are known to those skilled in the art and can be performed using a syringe, a microcatheter and the like, such as intraarterial injection, intravenous injection or the like.
The dosage varies depending on the patient's weight, age, symptoms, administration method and the like, and a person skilled in the art can appropriately select an appropriate dosage. The embolic agent of the present embodiment is administered in the form of an injection agent, with the copolymer concentration preferably being 20 mg/L or more and 60 mg/L or less.
The dosage of the commercially available Onyx is generally limited to about 4.5 mL or less per day in an adult (body weight 60 kg) due to the toxicity of the solvent DMSO. However, the embolic agent of the present embodiment is water-soluble and can be administered without using DMSO. Therefore, the embolic agent of the present embodiment can be administered in a larger dosage than Onyx, for example, more than about 4.5 mL per day in a typical adult (body weight 60 kg). Alternatively, when the required amount at the administration site is small, for example, the amount can be about 4.5 mL or less per day in a typical adult (body weight 60 kg).
The number of administrations may be a single administration of the above-mentioned dosage, or the above-mentioned dosage may be administered once every week, every two weeks, three weeks, four weeks, one month, two months, three months, or half a year, or may be administered twice or more times. Note that the embolic agent of the present embodiment is water-soluble and, unlike conventional embolic agents such as EVOH or the like, can be formulated to contain no organic solvents harmful to the body such as DMSO, so that the required dosage can be administered locally in a single dose.
The embolic agent of the present embodiment can be used as a pharmaceutical composition in combination with a pharmaceutically acceptable carrier.
As the pharmaceutically acceptable carrier, those usually used in the preparation of pharmaceutical compositions can be used without any particular limitation. More specifically, for example, solvents for injections such as water, ethanol, glycerin and the like can be mentioned.
The pharmaceutical composition may further contain additives. Examples of the additives include lubricants such as calcium stearate, magnesium stearate or the like; stabilizers such as benzyl alcohol, phenol or the like; solubilizers such as benzyl benzoate, benzyl alcohol or the like; antioxidants; preservatives and the like.
The pharmaceutical composition can be formulated by appropriately combining the above-mentioned embolic agent with the above-mentioned pharmaceutically acceptable carriers and additives, and mixing them in a unit dosage form required for the generally accepted pharmaceutical practice.
The dosage form of the pharmaceutical composition is preferably an injection agent.
The pharmaceutical composition is preferably used for the treatment of diseases to which known embolic agents are applicable. Such diseases include cerebral arteriovenous malformation; uterine fibroids, brain tumors, and liver cancer (the embolic agent of the present embodiment can be applied to the arterial embolization for these diseases); cerebral aneurysm; dural arteriovenous fistula; coronary arteriovenous fistula; bleeding due to vascular damage caused by trauma; nosebleeds; obstetric bleeding (atonic bleeding, placental abruption) and the like.
In one embodiment, the present invention provides a method for treating a disease, including administering to a patient in need of treatment a therapeutically effective amount of the above-described embolic agent.
The diseases include the same as those exemplified above in the pharmaceutical composition.
In one embodiment, the present invention also provides a use of the above-mentioned embolic agent for the manufacture of a pharmaceutical composition for the treatment of a disease.
In one embodiment, the above-mentioned embolic agent and contrast agent can be included in a kit for vascular embolization.
Examples of the contrast agent include gadolinium, Gd-DTPA, Gd-DTPA-BMA, Gd-HP-DO3A, iodine, iron, iron oxide, chromium, manganese, tantalum, and complexes and chelate complexes thereof.
The present invention will be described below with reference to the Examples, but the present invention is not limited to the following Examples.
(Preparation of cationic a polymer (poly(cation-adj-π)))
The cationic π polymer (poly(cation-adj-π)) was prepared by dissolving a cationic functional group-containing monomer (0.5 M), an aromatic group-containing monomer (0.5 M), and 2-oxoglutaric acid (0.25 mM) as a photopolymerization initiator in DMSO, and irradiating the resulting mixture with 365 nm UV light (4 mW/cm2) at room temperature (approximately 25° C.) for 11 hours to copolymerize the monomers to obtain a cationic π polymer.
The combinations of the cationic functional group-containing monomer and the aromatic group-containing monomer used are as shown in the table below.
As a representative result, the NMR spectrum of the cationic π-polymer (P(ATAC-adj-PEA)) in a state dissolved in DMSO prepared using ATAC and PEA is shown in
As for the measurement conditions for 1H-NMR measurement, each polymer was dissolved in a deuterated DMSO (DMSO-d6) solution at a concentration of 1 to 5 mg/mL, and analyzed using a 1H-NMR (Agilent 500 MHz).
As shown in
In addition, the NMR spectra of each P(ATAC-adj-BZA), P(ATAC-adj-PDEA), and P(ATAC-adj-PSEA) is shown in
As shown in
Furthermore, P(ATAC-adj-PEA) was prepared in the same manner as described above, with a total monomer concentration of 1.0 M, using 0.25 mM of 2-oxoglutaric acid as a polymerization initiator, and DMSO as a solvent, and adjusting the molar ratio of ATAC to PEA. The copolymerization rate of the cationic functional group-containing monomer (ATAC) and the aromatic group-containing monomer (PEA) was determined by analyzing the polymers at different reaction times using a 1H-NMR (Agilent 500 MHz). The results are shown in
As shown in
Next, the solvent of each of the obtained cationic 2-polymers was changed from DMSO to distilled water by dialysis, and the polymer was freeze-dried (kept at −40° C. under vacuum (<30 Pa) for several hours to several days depending on the amount), and then dissolved in water to prepare polymer aqueous solutions at 30 mg/mL, 40 mg/mL, and 50 mg/mL.
For the qualitative blood agglomeration test, 150 μL of polymer solutions with different concentrations (30 mg/mL, 40 mg/mL, or 50 mg/mL) were each added to a well plate to cover the entire bottom surface with the polymer. Then, the same volume of citrated blood was added to each well. The wells were repeatedly washed with saline until the solution was clear to remove all non-agglutinated blood components (see
As shown in
The above-described results demonstrates that the cationic π-polymer can form a stable gel with blood under physiological conditions.
Subsequently, a quantitative blood agglomeration test was carried out as follows. First, 500 μL of citrated blood was first added to a microcentrifuge tube, and different amounts (42 μL to 320 μL) of polymer (P(ATAC-adj-PEA)) aqueous solutions with different concentrations (30 mg/mL, 40 mg/mL, or 50 mg/mL) were slowly added to the blood. After injection, the agglomerates were immediately taken out and the liquid on the surface was removed. Then, the weight of the agglomerates was measured. The results are shown in
As shown in
Rheological tests were performed on the agglomerates obtained by adding 600 L of a 40 mg/mL aqueous solution of the polymer (P(ATAC-adj-PEA)) to 1 mL of citrated blood using an ARES-G2 rheometer (TA Instruments). A control coagulation was obtained by adding 150 μL of a 0.1M aqueous solution of calcium chloride (CaCl2) to 500 L of citrated blood. The results are shown in
As shown in
An injection force test was conducted using a 1 mL plastic syringe (see
As shown in
Next, an injection test was also conducted using a 1 mL plastic syringe and a microcatheter (see
As shown in
A polyethylene tube (ID 0.28 mm, OD 0.61 mm) filled with a polymer (P(ATAC-adj-PEA)) aqueous solution of different concentrations (30 mg/mL, 40 mg/mL, or 50 mg/mL) was passed through a thick polyethylene tube (ID 1.4 mm, OD 1.9 mm) containing 0.1 mL of citrated blood, and the same amount of each polymer solution was injected. After leaving it for 30 minutes, the force (N) when the thin polyethylene tube was withdrawn at a speed of 1.0 mm/min was measured (see
As shown in
Under anesthesia, a 1 cm long skin incision was made on the right dorsal side of an 8-week-old male Sprague-Dawley rat to create a subcutaneous pocket, and a 40 mg/mL polymer (P(ATAC-adj-PEA)) hydrogel disk (diameter 5 mm, thickness 1 mm) was placed in the subcutaneous pocket.
The hydrogel of the polymer (P(ATAC-adj-PEA)) was prepared by the following method and then cut to the above-described size. First, monomers (ATAC 1.2M and PEA 1.2M) and 2-oxoglutaric acid (6 mM) as a polymerization initiator were dissolved in DMSO. Next, the mixture was poured into a reaction cell consisting of a pair of glass plates. Polymerization was carried out by irradiating the plate with 365 nm UV light (4 mW/cm2) at 1 mm intervals at room temperature (about 25° C.) for 11 hours in a glove box. After polymerization, the prepared hydrogel was immersed in a large amount of saline to wash away DMSO and residual monomers, and a hydrogel was obtained.
The incision was then sutured. Rats that underwent only surgical incision served as controls. Blood biochemistry tests were performed on the 7th and 28th days after surgery. The rats' venous blood was centrifuged to obtain serum for testing. The concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine (CREA), and urea nitrogen (BUN) in serum were measured by a specialized laboratory (SRL, Inc., Tokyo, Japan). In general, the amounts of ALT and AST in blood are indicators of liver function, and the amounts of CREA and BUN in blood are indicators of kidney function. The results are shown in
As shown in
In addition, after the rats were euthanized on the 7th and 28th days after surgery, tissue sections were prepared from the area where 40 mg/mL polymer (P(ATAC-adj-PEA)) was injected, the area where the hydrogel was implanted, and the area where the surgical incision was made, and histological analysis (hematoxylin and eosin (H&E) staining) was also performed. The results are shown in
As shown in
Under anesthesia, a 1 cm longitudinal incision was made in the fore thigh of the right hind leg of 8-week-old male Sprague-Dawley rats, the femoral artery was exposed under a surgical microscope, and then 0.1 mL of 40 mg/mL polymer (P(ATAC-adj-PEA)) aqueous solution was injected distal to the artery using a 32-gauge needle. The incision was then closed, and the rats were allowed to recover from the anesthesia. Rats injected with the same amount of saline served as controls. Five minutes after surgery, the skin color of the hind legs was visually observed. In addition, the surface temperature of the hind legs was measured using a thermograph (Optris, PI640i). The results are shown in
As shown in
Five minutes after the operation, the rats were euthanized, and the right hind limbs were taken to prepare tissue sections and to perform histological analysis (H&E staining for tissue observation and acid blue staining for polymer observation). The results are shown in
As shown in
A 40 mg/mL aqueous solution of polymer (P(ATAC-adj-PEA)) containing tantalum powder (0.25 g/mL) was prepared prior to surgery and tested at different injection volumes (0.1 mL, or 2 μL or more and 3 μL or less). In the first test, 0.1 mL of the polymer aqueous solution containing tantalum powder was injected into the right femoral artery of 8-week-old male Sprague-Dawley rats within 5 seconds. 45 minutes after injection, a CT scan of the right hind limb was taken to confirm embolization. The results are shown in the left side of
In the next test, the polymer aqueous solution containing tantalum powder was injected as a one-shot injection (2 μL or more and 3 μL or less) into the right femoral artery of 8-week-old male Sprague-Dawley rats using the same procedure as described above. Three hours after injection, a CT scan of the right hind limb was taken to confirm embolization. The results are shown on the right side of
The CT image on the left side of
The CT image on the right side of
These results demonstrate that by appropriately adjusting the injection amount and selecting the injection site, embolism can be formed at a desired site and in a desired area within the body.
According to the embolic agent of the present embodiment, it is possible to provide an embolic agent that has vascular embolization properties equivalent to those of conventional embolic agents, while being easy to inject with a syringe and having excellent safety and stability in the living body.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-030098 | Feb 2022 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2023/007042 | 2/27/2023 | WO |
