Iodine-containing polysaccharide as well as synthetic method and application thereof

Abstract

The invention discloses iodine-containing polysaccharide, which is characterized in that the molecular structure of the iodine-containing polysaccharide takes hydrophilic natural polysaccharide as a skeleton, and the structure general formula is shown in the description, wherein R is selected from hydrogen or derived triiodo benzoyl and is not all hydrogen; the structural formula of the derived triiodo benzoyl is shown in a description, wherein R minute is selected from one or two of hydrogen, methyl, methylamino, acetamido, N minute-methyl carbamoyl, methoxyl acetamido, N-methyl acetamido or alkyl. The high-substituted iodine-containing polysaccharide provided by the invention has the outstanding advantages, relative to iodine-containing micromolecule, that after the iodine-containing micromolecule is polymerized, cytotoxicity is greatly reduced, and the problem of micromolecule leakage caused by diffusion is avoided; in addition, a CT contrast agent provided by the invention is high in iodide content, good in contrast effect, low in cytotoxicity, and capable of being used as a blood vessel X-ray CT contrast agent for clinical CT examination and diagnosis.

Description

technical field [0001] The invention belongs to the field of macromolecular materials and CT contrast agents, and in particular relates to an iodine-containing polysaccharide, a synthesis method thereof, and an application in preparing nanometer CT contrast agents. Background technique [0002] X-ray tomography (CT) is currently one of the most widely used non-invasive inspection methods in clinical practice. It has a wide range of applications, high efficiency, high speed, and relatively low cost. It can provide high-precision and non-overlapping three-dimensional tissue density images; in addition In recent years, the emergence of some combined diagnostic methods (PET / CT, SPECT / CT) has made CT technology have a wider application / upgrade space. However, human soft tissues have similar densities and have similar X-ray absorption coefficients; for some soft tissue examinations, CT contrast agents must be used to improve the contrast between tissues. At present, the most wide...

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Problems solved by technology

Patent US20050036946A1 discloses a method of using common biomedical materials PEG, PEO-PPO-PEO, amphiphilic degradable polyester molecules, etc. to modify triiodobenzoyl groups at chain ends, which can be formed by self-assembly in aqueous solution Iodine-containing nanoparticles, but the theoretical maximum iodine content is low; the patent US8258190B2 entraps small iodine-containing molecules in nanoparticles as a CT contrast agent. The method is simple, but the theoretical iodine content is low, and there are shortcomings of small iodine-containing molecules leaking

Available literature has reported that iodine-containing microspheres or nanoparticles formed by emulsion copolymerization of hydroxyethyl methacrylate triiodobenzoate and other monomers are used as CT contrast agents, and the reaction is controllable. The prepared nanoparticles The size is uniform, but such materials are not biodegradable; there are also iodine-containing nanoemulsions prepared by using phospholipids, amphiphilic polymers and synthetic lipiodol as CT contrast agents, and their iodine content is high, but the stability of such emulsions insufficient

There is only one report on the preparation of iodine-containing nanoparticle CT contrast agent by self-assembly of natural polysaccharides substituted with iodine-containing groups (Biomaterials2009, 30(29), 5667). In the literature, 2,3,5-triiodobenzoyl is grafted on the side chain of cellulose acetate, and the iodine-containing nanoparticle CT contrast agent is prepared by precipitation in Tween 80 aqueous solution; in this method, the polysaccharide backbone is hydrophobic, After grafting hydrophobic 2,3,5-triiodobenzoyl groups, they cannot self-assemble into nanoparticles in aqueous solution, and can only form nanoparticles with the help of surfactants; in addition, the 2,3, The iodine content of 5-triiodobenzoyl cellulose acetate is low, the stability of the prepared nanoparticles is poor, and the practical value is low

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