Radioactive liquid embolic

Abstract

Liquid embolic preparations and medical treatment methods of using those preparations are described. In some embodiments, the preparations or solutions can transition from a liquid to a solid for use in the embolization. The preparations can include biocompatible polymers with covalently bound radioactive iodine isotopes.

Description

FIELD

Described herein generally are liquid embolic and polymer particle preparations and medical treatment methods using those preparations.

SUMMARY

Described herein generally are liquid embolic preparations and medical treatment methods using those preparations. In some embodiments, the preparations or solutions can transition from a liquid to a solid for use in the embolization of arteriovenous malformations (AVM's) and solid tumors. The preparations can include biocompatible polymers with covalently bound radioactive iodine isotopes and a non-physiological solution.

Liquid embolics are introduced through a microcatheter in the liquid state and transition to the solid state once in the body. The transition is generally controlled either by reaction or precipitation. For the materials functioning by reaction, the materials are introduced in a liquid state and undergo a chemical reaction to transition to a solid. For the materials functioning by precipitation, the materials are introduced in a non-physiological condition and transition to a solid upon exposure to physiological conditions. Non-physiological conditions include water miscible organic solvents, temperature, and pH.

Some embodiments are directed to liquid embolic formulations that can be deployed into the vasculature using standard practices and microcatheters/catheters to occlude blood flow. In some embodiments, the liquid embolic formulations are comprised of a biocompatible polymer with biostable or biodegradable linkages to aromatic rings containing a plurality of iodine, wherein some of the iodine atoms are stable and some are radioactive and a water miscible solvent that dissolves the biocompatible polymer.

In one embodiment, the liquid embolic polymer can include 2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-yloxy)ethoxy)ethyl acrylate and hydroxyethyl methacrylate. In some embodiments, the liquid embolic polymer is that polymer sold under the name PHIL by MicroVention, Inc.

In one embodiment, the biodegradable linkage is susceptible to breakage via hydrolysis. In another embodiment, the biodegradable linkage is susceptible to breakage via enzymatic action. In another embodiment, the linkage is biostable and/or substantially biostable. Biostable can be non-biodegradable.

In one embodiment, the stable iodine isotope is ¹²⁷I and the radioactive iodine isotope is ¹²³I, ¹²⁴I, ¹²⁵I, or ¹³¹I. In one embodiment, the radioactive iodine isotope is ¹²³I. In one embodiment, the radioactive iodine isotope is ¹²⁴I. In one embodiment, the radioactive iodine isotope is ¹²⁵I. In one embodiment, the radioactive iodine isotope is ¹³¹I.

In some embodiments, the polymer particles or liquid embolic polymers described herein can include folic acid or a derivatized version thereof.

DETAILED DESCRIPTION

Liquid embolic preparations are described. In some embodiments, medical treatment methods using the liquid embolic preparations are described.

In general terms, the liquid embolic preparation includes (i) a biocompatible polymer with an aromatic ring with a plurality of iodine atoms coupled via biodegradable or biostable linkages and (ii) a water miscible solvent that dissolves the biocompatible polymer.

In some embodiments, a function of the liquid embolic polymer is to solidify in the vasculature or other anatomical structure when coming in contact with blood or other physiological fluid to occlude the vessel or structure and to permit visualization of the polymer when imaged using medically relevant techniques. The liquid embolic polymer's solubility is achieved with the judicious selection of the composition of the polymer to ensure that it is essentially insoluble at physiological conditions. The liquid embolic polymer includes and/or is a reaction product of a prepolymer solution including monomers containing visualization species and optionally other monomers. The ratio of monomers with monomers containing visualization species and other monomers is dependent on the structure of the monomers and is best determined experimentally.

The monomer or monomers with visualization species can impart visibility of the liquid embolic polymer when imaged using a medically relevant imaging technique such as fluoroscopy or computed tomography. Characteristic features of the monomers with visualization species are cores that are visible under medically relevant imaging techniques and a polymerizable moiety attached to the core with a biodegradable linkage.

Visualization of the polymer under fluoroscopy and CT imaging can be imparted by the use of monomers with cores containing iodine, particularly aromatic rings with a plurality of iodine atoms. In one embodiment, a core containing iodine is triiodophenol. Concentrations of iodine to render the liquid embolic visible using fluoroscopy or CT imaging can range from 20% to 50% w/w of the liquid embolic solution.

Polymerizable moieties can include those that permit free radical polymerization, including acrylates, methacrylates, acrylamides, methacrylamides, vinyl groups, and derivatives thereof. Alternatively, other reactive chemistries can be employed to polymerize the liquid embolic polymer, i.e. nucleophile/N-hydroxysuccinimide esters, nucleophile/halide, vinyl sulfone/acrylate or maleimide/acrylate. In some embodiments, polymerizable moieties are acrylates and acrylamides.

Biodegradable linkages permit the separation of the visualization core from the polymer. After separating from the polymer, the core is removed by diffusion or the cells comprising the foreign body response to the polymer. Biodegradable linkages can be separated into two types, those susceptible to hydrolysis and those susceptible to enzymatic action. Linkages susceptible to hydrolysis are generally esters or polyesters. Ester can be introduced by reacting hydroxyl groups with strained anhydrides, such as succinic or glutaric anhydride, or cyclic esters, such as lactide, glycolide, ε-caprolactone, and trimethylene carbonate. The rate of degradation can be controlled by the selection of the ester and the number of the esters inserted into the biodegradable linkages. Linkages susceptible to enzymatic action can generally be peptides that are degraded by particular enzymes, such as matrix metalloproteinases, collagenases, elastases, cathepsin. Peptide sequences degraded by matrix metalloproteinases can include Gly-Pro-Gln-Gly-Ile-Ala-Ser-Gln (SEQ ID NO: 1), Gly-Pro-Gln-Gly\Pro-Ala-Gly-Gln (SEQ ID NO: 2), Lys-Pro-Leu-Gly-Leu-Lys-Ala-Arg-Lys (SEQ ID NO: 3), Gly-Pro-Gln-Ile-Trp-Gly-Gln (SEQ ID NO: 4), and Gln-Pro-Gln-Gly-Leu-Ala-Lys (SEQ ID NO: 5). Peptide sequences degraded by cathepsin include Gly-Phe-Gln-Gly-Val-Gln-Phe-Ala-Gly-Phe (SEQ ID NO: 6), Gly-Phe-Gly-Ser-Val-Gln-Phe-Ala-Gly-Phe (SEQ ID NO: 7), and Gly-Phe-Gly-Ser-Thr-Phe-Phe-Ala-Gly-Phe (SEQ ID NO: 8). Peptide sequences degraded by collagenase include Gly-Gly-Leu-Gly-Pro-Ala-Gly-Gly-Lys (SEQ ID NO: 9) and Ala-Pro-Gly-Leu (SEQ ID NO: 10). Peptide sequences degraded by papain include Gly-Phe-Leu-Gly (SEQ ID NO: 11). Peptide sequences degraded by caspase-3 include Asp-Glu-Val-Asp-Thr (SEQ ID NO: 12). The rate of degradation can be controlled by the peptide sequence selection.

Other monomers that can be used can have two characteristic features, namely containing a polymerizable moiety and having a structure that is conducive to the desired solubility characteristics. Preferred polymerizable moieties can be those that permit free radical polymerization, including acrylates, methacrylates, acrylamides, methacrylamides, vinyl groups, and derivatives thereof. Alternatively, other reactive chemistries can be employed to polymerize the liquid embolic polymer, i.e. nucleophile/N-hydroxysuccinimide esters, nucleophile/halide, vinyl sulfone/acrylate or maleimide/acrylate. In some embodiments, polymerizable moieties include acrylates and acrylamides. In general, the other monomer can compensate for the monomers with visualization species. If a prepared polymer is too hydrophobic for dissolution in water miscible solvent, more hydrophilic monomers can be introduced to alter the solubility. If a prepared polymer is too hydrophilic and is soluble in water, more hydrophobic monomers can be introduced to alter the solubility. Other monomers can include hydroxyethyl methacrylate, t-butyl acrylate, t-butyl acrylamide, n-octyl methacrylate, and methyl methacrylate.

In some embodiments, liquid embolic polymers can be polymerized from solutions of monomers with visualization species and optionally other monomers. The solvent used to dissolve the monomers can be any solvent that dissolves the desired monomers. Preferred solvents include methanol and acetonitrile. In other embodiments, the solvent can be dimethylsulfoxide (DMSO) or tetrahydrofuran (THF). In some embodiments, the solvent can be water.

Polymerization initiators can be used to start the polymerization of the monomers in the solution. The polymerization can be initiated by reduction-oxidation, radiation, heat, or any other known method. Radiation cross-linking of the prepolymer solution can be achieved with ultraviolet light or visible light with suitable initiators or ionizing radiation (e.g. electron beam or gamma ray) without initiators. Polymerization can be achieved by application of heat, either by conventionally heating the solution using a heat source such as a heating well, or by application of infrared light to the prepolymer solution.

In some embodiments, the polymerization initiator is azobisisobutyronitrile (AIBN) or a water soluble AIBN derivative (2,2′-azobis(2-methylpropionamidine) dihydrochloride). Other initiators can include AIBN derivatives, including, but not limited to 4,4′-azobis(4-cyanovaleric acid, and other initiators such as N,N,N′,N′-tetramethylethylenediamine, ammonium persulfate, benzoyl peroxides, and combinations thereof, including azobisisobutyronitriles. In some embodiments, initiator concentrations can be less than about 0.5% w/w of the prepolymer solution. The polymerization reaction can be run at elevated temperatures, such as about 80° C. After the polymerization is completed, the liquid embolic polymer can be recovered by precipitation in a non-solvent and dried under vacuum.

In one embodiment, the liquid embolic polymer can include 2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-yloxy)ethoxy)ethyl acrylate and hydroxyethyl methacrylate. In some embodiments, the liquid embolic polymer is that polymer sold under the name PHIL by MicroVention, Inc.

The substitution of radioactive iodine for stable iodine can be performed at any of the steps in the synthetic procedure. In one embodiment, substitution of radioactive iodine for stable iodine can occur after the conclusion of the preparation of the liquid embolic polymer. After the liquid embolic polymer has been prepared, it is re-dissolved in dimethyl sulfoxide and the sodium salt of the radioactive iodine is added. After the sodium salt has been completely dissolved, 30% hydrogen peroxide in water is added. The reaction solution can be optionally heated to facilitate the substitution. When the reaction is complete, the liquid embolic polymer is purified with repeated precipitation in water and dissolution in dimethyl sulfoxide.

In another embodiment, the substitution can be performed on the monomer containing a polymerizable moiety with a biostable or biodegradable linkage to an aromatic ring containing a plurality of iodine atoms. The same reaction procedure as described for the liquid embolic polymer may be used for the monomer.

Embodiments described herein can use iodine radioisotopes that include ¹²³I, ¹²⁴I, ¹²⁵I, and ¹³¹I. Each isotope has distinct properties that ablate tissue and permit imaging. In one embodiment, the isotope used is ¹³¹I due to its destructive beta emissions, gamma emissions that can be used for medical imaging, and short half-life.

In some embodiments, polymers described herein can include a monomer including at least one iodine. Examples of iodinated monomers include, but are not limited to triiodophenol, 1-((2-(methacryloyloxy)ethoxy)carbonyloxy)ethyl-3,5-diacetamido-2,4,6-triiodobenzoate, and 2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-yloxy)ethoxy)ethyl acrylate. However, in some embodiments, any monomer including iodine can be used.

In some embodiments, a polymer particle or liquid embolic polymer includes triiodophenol and 3,6-dimethyl-1,4dioxane-2,5 dione.

In some embodiments, a polymer particle or liquid embolic polymer includes 2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-yloxy)ethoxy)ethyl acrylate and hydroxyethyl methacrylate.

In some embodiments, a polymer particle or liquid embolic polymer includes triiodophenol and hydroxyethyl methacrylate.

In some embodiments, a polymer particle or liquid embolic polymer includes a triiodophenol with a chain extended lactide units and capped with an acrylate.

In some embodiments, a radioactive iodine salt can be used with hydrogen peroxide to exchange iodine atoms on an iodinated monomer with radioactive iodine. In some embodiments, the salt is a sodium salt.

In some embodiments, the polymer particles can have a radioactive yield. This radioactive yield can be developed under homogenous conditions. Therein, the radioactive yield can be between about 1% and about 15%, between about 1% and about 5%, between about 5% and about 20%, between about 10% and about 15%, between about 5% and about 15%, between about 10% and about 12%, or between about 5% and about 30%.

In other embodiments, radioactive yield can be developed under heterogeneous conditions. Therein, the radioactive yield can be between about 1% and about 75%, between about 50% and about 75%, between about 50% and about 60%, between about 70% and about 75%, between about 70% and about 80%, between about 40% and about 45%, or between about 70% and about 75%.

In some embodiments, the polymer particles can have a radiochemical purity of between about 50% and about 90%, between about 70% and about 90%, between about 70% and about 75%, between about 85% and about 90%, between about 80% and about 90%, greater than about 70%, greater than about 80%, greater than about 85%, greater than about 90%.

In some embodiments, the liquid embolic polymers can have a radioactive yield. This radioactive yield can be developed under homogenous conditions. Therein, the radioactive yield can be between about 1% and about 15%, between about 1% and about 5%, between about 5% and about 20%, between about 10% and about 15%, between about 5% and about 15%, between about 10% and about 12%, or between about 5% and about 30%.

In other embodiments, radioactive yield can be developed under heterogeneous conditions. Therein, the radioactive yield can be between about 1% and about 75%, between about 50% and about 75%, between about 50% and about 60%, between about 70% and about 75%, between about 70% and about 80%, between about 40% and about 45%, or between about 70% and about 75%.

In some embodiments, the liquid embolic polymers can have a radiochemical purity of between about 50% and about 90%, between about 70% and about 90%, between about 70% and about 75%, between about 85% and about 90%, between about 80% and about 90%, greater than about 70%, greater than about 80%, greater than about 85%, greater than about 90%.

The water miscible solvent is used to dissolve of the liquid embolic polymer. Concentrations of the liquid embolic polymer in the aqueous solution can range from about 2.5% to about 25%, more preferably between about 5% and about 15%.

In some embodiments, the liquid embolic device is prepared by dissolving the liquid embolic polymer in the water miscible solvent, adding to an appropriate vial or other container, and capping the vial. A preferred method of sterilization before use is autoclaving.

The liquid embolic formulation is removed from the vial using a needle and syringe. To prevent premature liquid embolic polymer deposition, the delivery catheter is flushed with a bolus of the same water miscible solvent as was used to dissolve the liquid embolic polymer. This flushing prevents clogging of the delivery catheter with the liquid embolic polymer. The syringe containing the liquid embolic formulation is then connected to the proximal end of delivery catheter, such as a microcatheter, cannula, or the like, positioned in the desired vascular or other anatomic site.

As the liquid embolic formulation is injected, it pushes the water miscible solvent flushing solution out of the microcatheter. The progress of the liquid embolic formulation inside the delivery catheter can be observed using an imaging technique compatible with the visualization species selected. With continued injection, the liquid embolic formulation enters the target delivery site. The solidified liquid embolic polymer provides long-term occlusion of the target site. Over time, the biodegradable linkages binding the visualization species to the liquid embolic polymer are broken and the visualization of the liquid embolic polymer is diminished.

In other embodiments, radioactive iodine-containing polymers as described herein can be used to target cancer at the cellular level. In some embodiments, these polymers can be those described in the Examples.

The radioactive iodine-containing polymers can be formed into particles. These particles can have diameters of about 10 nm to about 50 nm, about 10 nm to about 40 nm, about 10 nm to about 30 nm, about 10 nm to about 20 nm, about 20 nm to about 50 nm, about 30 nm to about 50 nm, about 40 nm to about 50 nm, or about 20 nm to about 40 nm. Many different methods can be used to prepare particles from the herein described iodine-containing polymers. In one embodiment, particles can be formed by forcing an iodine-containing polymer through a nozzle at high pressure in a medium such as air, water, or oil. In some embodiments, the nozzle can be like the nozzle used for ink jet printing. The resulting particles may then be separated by size using, for example, electrostatic techniques, centrifuge, filtering, sieving, or a combination thereof.

The polymer particles or liquid embolic particles described herein can be covalently functionalized with folic acid.

In one embodiment, folic acid can be functionalized using poly(ethylene glycol). In one embodiment, a functionalized folic acid can have a structure

wherein n is 0-100.In another embodiment, a functionalized folic acid can have a structure

In some embodiments, a functionalized folic acid can react with hydroxyl groups on an embolic or other particle.

In an alternative embodiment, folic acid may be bonded to the polymer structure at the time of synthesis and formed into particles by the methods described.

Folic acid (vitamin B9, folate) can be used for cell division. Therefore, rapidly dividing cells such as cancer cells overexpress folate receptors on their surface. In some embodiments, the radioactive polymer with functionalized folic acid can be taken up by folate receptors on the cancer cells. This can make radiotherapy more targeted to cancer cells relative to normal cells. Depending on the dose, the radiation may be used therapeutically to destroy or damage the cancerous cells, or may be used as a diagnostic marker at lower radiation dose.

To deliver the radioactive particles functionalized with folic acid, the particles may be placed in a suspension with a biocompatible liquid such as lipiodol, contrast, saline solution, or the like. The suspension may require mixing or agitation prior to use depending on the size and number of particles. In some embodiments, the suspension may be directly injected into a tumor through a catheter, microcatheter, syringe/needle, or the like. In another embodiment, the suspension may be infused into the bloodstream as a chemotherapy agent.

Once injected at either a therapeutic or a diagnostic dose, an external monitoring instrument, such as a gamma camera, may be used to locate areas within the body of high uptake of particles. This method can be used to detect, for example, previously unknown metastases. Since it acts at the cellular level, this method would be sensitive to even metastases of only a few cells outside the original tumor location.

In some embodiments, a container is provided including a therapeutic amount of polymer polymers functionalized with folic acid. In some embodiments, the container can be a vial, a bottle, a syringe, an IV bag, an IV bottle, or the like. In some embodiments, the container can be any container that can be used to transfer the polymer functionalized with folic acid into a patient using a medically relevant method.

In some embodiments, methods of treatment using the herein described radioactive polymer particles are described. Methods can include injecting a solution including the polymer particles into a treatment site. The treatment site can be a vessel. In other embodiments, the treatment site can be any lumen in need of treatment.

In some embodiments, methods of treatment using the herein described radioactive liquid embolic polymers are described. Methods can include injecting a solution including the dissolved liquid embolic polymer particles into a treatment site. Upon encountering a condition, the liquid embolic polymers precipitate. The condition can be a change in pH, a change in temperature, or a change in solubility. The treatment site can be a vessel. In other embodiments, the treatment site can be any lumen in need of treatment.

Polymer particles and/or liquid embolic polymers described herein can be delivered using a needle and syringe and/or injected through a catheter or microcatheter.

Kits including the herein described polymer particles are also described. Kits can include a container including a solution. The solution can include a radioactive polymer particle as described herein. The kit can include instructions for use. The kits can also include a syringe or a catheter or microcatheter for delivery.

Kits including the herein described liquid embolic polymers are also described. Kits can include a container including a solution. The solution can include a radioactive liquid embolic polymer as described herein. The kit can include instructions for use. The kits can also include a syringe or a catheter or microcatheter for delivery.

In some embodiments, the kits can further include a solution used to flush the particle solution or liquid embolic polymer through a catheter or microcatheter.

The container can be a vial, tube, syringe, or the like.

Example 1

Preparation of an Iodine-Containing Monomer

To 250 milliliters of toluene, 15 g triiodophenol, 22.9 g 3,6-dimethyl-1,4-dioxane-2,5 dione, and 25 microliters of stannous octoate were added. The solution was refluxed for 18 hr. After cooling the solution to 25° C., 3 ml acryloyl chloride and 5.2 ml triethylamine dissolved in 50 ml toluene were added. The mixture was stirred for 5 hr, filtered, washed with water, and dried under vacuum.

Example 2

Preparation of an Iodine-Containing Polymer

To 3 milliliters of dimethyl sulfoxide, 1.8 g triiodophenol chain extended with an average of 5 lactide units and capped with an acrylate, 0.2 g of hydroxyethyl methacrylate, and 10 mg of azobisisobutyronitrile were added. Upon complete dissolution of all components, the solution was placed at 80° C. for 4 hours. After cooling to room temperature, the polymer was recovered by precipitation in ethyl ether and dried under vacuum.

Example 3

Exchanging Iodine on an Iodine-Containing Polymer (Prophetic)

To a dimethyl sulfoxide solution of the iodine-containing polymer of Example 2, Na ¹³¹I is added with stirring. After the Na ¹³¹I is completely dissolved, hydrogen peroxide (30% in aqueous solution) is added. The reaction is optionally heated to facilitate the exchange process. After 10 min of reaction time (or longer as needed), the DMSO solution is poured over distilled water to precipitate the iodine-containing polymer. The precipitate is filtered and subsequently redissolved in DMSO and reprecipitated in DI water twice more. The solid is then lyophilized to remove water and obtain the product as a solid.

Example 4

Preparation of Liquid Embolic Formulation

To 9 g of dimethyl sulfoxide, one gram of the polymer of Example 3 was added. The liquid embolic formulation was then aliquoted into vials and capped. The vials were autoclaved at 121° C. for 15 minutes.

Example 5

Electrophilic Radioiodination of PHIL with Na ¹²⁵I Under Homogenous Conditions

An excess equivalent of Na ¹²⁵I (dissolved in 10⁻⁵ M NaOH solution, pH=8) is added to a solution of 1000 ppm liquid embolic including 2,4,6-triiodophenyl 5-(2-(2-(acryloyloxy)acetoxy)acetoxy)-2-methyl-4-oxohexanoate and hydroxyethyl methacrylate in tetrahydrofuran (THF). In one embodiment, this liquid embolic is sold under the name PHIL by MicroVention, Inc. After an extend reaction time, e.g. 30 min, 60 min, and 90 min, the reaction is quenched, and the polymer is recovered by precipitation in water. The radioactive yield and the polymer recovery percentage are listed in Table 1.

	TABLE 1
	Summary of the yields and conditions of
	liquid embolic electrophilic radioiodination.
		Reaction	Radioactive	Polymer recovery
	Solvent Used	time	yield	percentage
	THF	90 min	11%	3.8%
	DMSO	90 min	2.5%	6.0%

Example 6

Electrophilic Radioiodination of PHIL with Na ¹²⁵I Under Heterogeneous Conditions

A solution of Na ¹²⁵I (101.72 mCi/mL) in 0.1% TFA in CH₃CN is added to a solution of liquid embolic polymer including 2,4,6-triiodophenyl 5-(2-(2-(acryloyloxy)acetoxy)acetoxy)-2-methyl-4-oxohexanoate and hydroxyethyl methacrylate (50-200 μg) in dichloromethane (80-120 μL). In one embodiment, this liquid embolic is sold under the name PHIL by MicroVention, Inc. To this solution, 50 μg of iodogen (1 mg/mL in DCM) is added. The solution is left to react at room temperature for 5-15 min. The radioactive yield is not benefitted from extending the reaction time to longer than 15 min. The reaction is quenched with sodium metabisulphite (10 mg/mL in PBS). The reaction is centrifuged at 2,000 rpm for 15 min to separate the pellet from the supernatant. The pellet is washed twice with dichloromethane. With this method, it is estimated that an average of 2.7 MBq radioactivity was obtained from 100 μg liquid embolic polymer starting material.

Example 7

Electrophilic Radioiodination of PHIL with Na ¹²⁵I Under Heterogeneous Conditions with Iodogen on a Milligram Scale

Na ¹²⁵I aliquots (2mCi-5mCi) were evaporated to dryness under the stream of sterile N₂. CH₂Cl₂ containing 0.1% TFA (v/v) was added to the Na ¹²⁵I residue, vortexed briefly and transferred into the radioiodination tube containing the suspension of PHIL in CH₂Cl₂. Iodogen was added and the radioiodination mixture was vortexed (˜1 min) and sonicated (˜5 min). CH₂Cl₂ was removed from the ¹²⁵I-PHIL pellet. The pellet was washed with 2×0.4 mL CH₂Cl₂, 1×1 mL Na₂S₂O₅ (10 mg/mL water), 1×1 mL distilled H₂O and dried under the vacuum. The dry ¹²⁵I-PHIL pellet was dissolved in 1 mL THF and subjected to ITLC and TLC analyses. The results are listed in Table 2.

TABLE 2
Summary of the yields and conditions of liquid embolic electrophilic
radioiodination using iodogen as the
oxidant on a milligram scale.
Starting material	50 mg PHIL*	100 mg PHIL
Radiochemical yield (%)	43.9%	73.8%
Specific activity (mCi/mg)	0.028 mCi/mg PHIL	0.028 mCi/mg PHIL
Radiochemical purity	73%	87%
*results calculated from average of two reactions.

Example 8

Electrophilic Radioiodination of PHIL with Na ¹²⁵I Under Heterogeneous Conditions with Chloroamine-T on a Milligram Scale

To the radioiodination tube containing the suspension of PHIL in CH₂Cl₂ and aliquot of Na ¹²⁵I in 1×10⁻⁵ M NaOH was added followed by chloramine-T and CH₂Cl₂ containing 0.1% TFA (v/v). The reaction mixture was vortexed for ˜2 min and sonicated ˜5 min. CH₂Cl₂ layer and the resuspended ¹²⁵I-PHIL pellet were washed with 1×1 mL Na₂S₂O₅ (10 mg/mL water). The organic and aqueous layers were removed and the solid residue washed again with 1×1 mL Na₂S₂O₅ (10 mg/mL water) and 2×1 mL distilled H₂O. The washed ¹²⁵I-PHIL pellet was dried under vacuum. The dry ¹²⁵I-PHIL pellet was dissolved in 1 mL THF and subjected to ITLC analyses. From two reactions using 12 mg of PHIL as the starting material, the radiochemical yield was 73.0%, the specific activity was 0.083 (mCi/mg), and the radiochemical purity was 97% (% by ITLC).

Example 9

Coupling Folic Acid to Radio Liquid Embolic

Synthesis of Folate-PEG-NH 2 (3)

Folic acid (1, 4.41 g, 10 mmol) is dissolved into a mixture of anhydrous dimethyl sulfoxide (DMSO, 100 mL) and triethylamine (TEA, 0.5 mL), and activated by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, 1.9 g, 10 mmol) and N-hydroxysuccinimide (NHS, 1.15 g, 10 mmol) under nitrogen anhydrous conditions for 2 hr at room temperature. One molar equivalent of poly(ethylene glycol) bis(amine) is dissolved in 50 mL of DMSO. Under stirring, the solution of activated folic acid is added dropwise into the solution of poly(ethylene glycol) bis(amine). The resulting mixture is stirred at room temperature for about 24 hr under nitrogen anhydrous condition. The final product 3 is purified by HPLC.

Synthesis of Folate-PEG-PHIL conjugate (4)

PHIL polymer (0.5 mmol) is dissolved in 50 mL of anhydrous DMSO followed by addition of N,N-carbonyldiimidazole (CDI, 0.81 g, 5 mmol). The reaction is stirred under anhydrous nitrogen for 4 hr. The Folate-PEG-NH 2 (3, 5 mmol) is dissolved in 10 mL of anhydrous DMSO. The resulting solution is added into the PHIL polymer solution dropwise. The reaction mixture is stirred for 6 hr at room temperature. The solution is dried using rotovap and the crude is re-dissolved in DMSO and purified by repeated precipitation in methyl tert-butyl ether to obtain the final product 4.

Example 10

Preparation of Nanoparticles

Nano/micro particles are prepared from the solution prepared in Example 9 using a precipitation procedure. The dimethyl sulfoxide solution is slowly dispersed into water with vigorous agitation. As dimethyl sulfoxide is dispersed within the water and diffuses into the water, small particles of radioactive polymer coupled with folic acid are formed. The particles can be collected and repeatedly washed with centrifugation. Finally, the particles are dried using lyophilization. If smaller particles sizes are required, they may be mechanically milled before being packaged appropriately.

Example 11

Preparation of Nanoparticles

Nano/micro particles are prepared from the solution prepared in Example 9 using an atomization procedure. The dimethyl sulfoxide solution is slowly injected through a heated needle with coaxial gas flow. As the dimethyl sulfoxide is evaporated by the gas, small particles of radioactive polymer coupled with folic acid are formed. The particles can be collected in water and repeatedly washed with centrifugation. Finally, the particles are dried using lyophilization. If smaller particles sizes are required, they may be mechanically milled before being packaged appropriately.

While the invention has been particularly shown and described with reference to particular embodiments, it will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.

Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

The terms “a,” “an,” “the” and similar referents used in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

Certain embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Of course, variations on these described embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Furthermore, numerous references have been made to patents and printed publications throughout this specification. Each of the above-cited references and printed publications are individually incorporated herein by reference in their entirety.

In closing, it is to be understood that the embodiments of the invention disclosed herein are illustrative of the principles of the present invention. Other modifications that may be employed are within the scope of the invention. Thus, by way of example, but not of limitation, alternative configurations of the present invention may be utilized in accordance with the teachings herein. Accordingly, the present invention is not limited to that precisely as shown and described.

Claims

1. A polymeric composition, comprising a non-physiological solution, and a folate-polymer conjugate that is a reaction product of: 1) A biocompatible polymer comprising a reaction product of: a first monomer including a polymerizable moiety having a biodegradable linkage to a visualization agent having at least one aromatic ring, wherein the at least one aromatic ring includes at least one iodine atom, wherein at least one of the at least one iodine atom is a radioactive isotope,and a second monomer comprising hydroxyethyl methacrylate; and2) A folate compound having the formula:

2. The polymeric composition of claim 1, wherein the biodegradable linkage is SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, or SEQ ID NO: 12.

3. The polymeric composition of claim 1, wherein n is 1, 2, 3, 4, 5, 6, or 100.

4. The polymeric composition of claim 1, wherein the radioactive isotope is 123I, 124I, 125I, 131I, or a combination thereof.

5. The polymeric composition of claim 1, wherein the radioactive isotope is 123I.

6. The polymeric composition of claim 1, wherein the radioactive isotope is 124I.

7. The polymeric composition of claim 1, wherein the radioactive isotope is 125I.

8. The polymeric composition of claim 1, wherein the radioactive isotope is 131I.

9. The polymeric composition of claim 1, wherein the first monomer is functionalized triiodophenol, 1-((2-(methacryloyloxy)ethoxy)carbonyloxy)ethyl-3,5-diacetamido-2,4,6-triiodobenzoate, 2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-yloxy)ethoxy)ethyl acrylate, or a combination thereof.

10. The polymeric composition of claim 1, wherein n is 1.

11. A polymeric composition, comprising a non-physiological solution and a folate-polymer conjugate, wherein: the folate-polymer conjugate comprises a visualization agent having at least one aromatic ring, wherein the at least one aromatic ring includes at least one iodine atom, wherein at least one of the at least one iodine atom is a radioactive isotope,the folate-polymer conjugate comprises the formula:

12. The polymeric composition of claim 11, wherein n is 1, 2, 3, 4, 5, 6, or 100.

13. The polymeric composition of claim 11, wherein n is 1.