CN1290505C - pH sensing controlable nanometer particle carried with 5-Fu and its prepn. method - Google Patents

Abstract

The present invention discloses a pH sensing controllable nanometer particle carrying 5-fluorouracil medicine and a preparation method thereof. The nanometer particle is in a structure in the shape of a nuclear shell of which the shell material is modified pullulan-sulfadimethoxine and the nuclear material is the acetyl portion of modified pullulan; the nanometer particle carrying medicine is consumingly accumulated and releases the medicine when pH is about 6.6 to 6.9, and realizes slow release and maintains granularity when pH is no less than 7.4; the encapsulation efficiency of the medicine is more than 80%. The method comprises the following steps: pullulan is dissolved in formamide solution in which hydrophobic modification is carried out; sulfadimethoxine is grafted in anhydrous 1, 4 dioxane; the prepared and modified pullulan-sulfadimethoxine and 5-fluorouracil are dissolved and dialyzed in dimethyl sulfoxide to form the nanometer particle carrying medicine. The present invention has the advantages that the water solubility of 5-fluorouracil is increased; the controllable release of medicine under the condition of specific pH value is easily realized by changing the conditions of the grafting extent of sulfadimethoxine, etc.; the preparation process is simple, and the particle is an ideal carrier of 5-fluorouracil.

Description

pH sensitive and controllable release nanoparticles loaded with 5-fluorouracil drug and preparation method

Technical field

The invention relates to a pH-sensitive and controllable release nanoparticle loaded with 5-fluorouracil drug and a preparation method thereof, which belongs to the nanoparticle technology used for loading 5-fluorouracil.

Background technique

5-Fluorouracil (5-Fluorouracil, abbreviated as 5-FU) is one of the earliest chemotherapeutic drugs, synthesized by Heidelberger in 1957. Has a lethal effect. It is mainly used clinically for breast cancer, colon cancer, rectal cancer, gastric cancer, liver cancer, ovarian cancer, cervical cancer, bladder cancer, prostate cancer and head and neck tumors. It is the first-line treatment drug for various malignant tumors and can also be used as radiation therapy sensitizers. Topical application can also treat basal cell carcinoma, and certain malignant skin diseases. However, it metabolizes quickly in the body and has a short half-life of only 5-10 minutes. Clinically, in order to achieve an effective blood drug concentration in the body, large doses, continuous administration or repeated administration are often used. The recognition rate of cells and diseased cells is poor, resulting in patients with loss of appetite, nausea, vomiting, stomatitis, gastritis, abdominal pain, diarrhea, and bloody stool in severe cases; bone marrow suppression is the main toxicity, manifested as leukopenia, thrombocytopenia and anemia ; hair loss, nail changes, dermatitis, increased skin pigmentation and other toxic side effects. In order to improve the drug efficacy, reduce the clinical dosage, prolong the administration interval, reduce the side effects of drugs on the human body, and improve the quality of life of patients during chemotherapy, the development of 5-fluorouracil controlled release nanocarriers has high clinical application value.

Nanoparticles as drug carriers are solid colloidal particles with a particle size between 10-1000nm. Nanoparticles are used as drug carriers. Due to the nanoscale size of the carrier, the drug can escape the phagocytosis of macrophages. Nanoparticles have an amphiphilic core-shell structure, the drug is wrapped in the hydrophobic core, and the hydrophilic shell has good water solubility, which can greatly increase the solubility of poorly soluble drugs in the aqueous phase, and is suspended or wrapped in The insoluble drug in nanoparticles can greatly improve the bioavailability of the drug in the aqueous environment due to its nano-scale particle size and the increased surface area in contact with the dissolution medium during dissolution, that is, to improve the efficacy of the drug. Since the pH value of tumor cell fluid is slightly lower than that of normal cells and is weakly acidic (pH≈6.8), if the drug carrier can be modified on the surface, the carrier can maintain nanoscale particle size and reduce the release capacity under the condition of normal body fluid pH value. However, at the pH of the tumor cell fluid, a large number of aggregates and strong release can achieve a controlled release effect with good targeting. 5-Fluorouracil has poor solubility in water, low bioavailability, and poor cell recognition. If 5-fluorouracil is loaded in a surface-modified pH-sensitive nanocarrier, its solubility can be significantly improved and its bioavailability can be increased. Achieve targeted and controlled release.

Contents of Invention

The purpose of the present invention is to provide a pH-sensitive controllable release nanoparticle loaded with 5-fluorouracil drug and a preparation method. The encapsulated nanoparticles prepared according to this technology have pH sensitive and controlled release characteristics. Its preparation method is simple.

The present invention is achieved through the following technical scheme, a pH-sensitive and controllable-release nanoparticle loaded with 5-fluorouracil drug, characterized in that the nanoparticle has a core-shell structure of 50-200nm, and its shell material is Modified pullulan-sulfidethoxine, its core material is the acetyl part of the modified pullulan, the drug-loaded nanoparticles strongly aggregate and release the drug at pH=6.6-6.9, and achieve slow release at pH=7.4 or more. release and maintain particle size, and its drug encapsulation rate is above 80%.

The preparation method of the above-mentioned drug-loaded nanoparticles is characterized in that it includes the following process:

1. Dissolve pullulan with a molecular weight of 100,000-200,000 in formamide solution to prepare a solution with a concentration of 10-15%, add acetic anhydride to the solution to modify pullulan hydrophobically, pullulan and The weight ratio of acetic anhydride is 1:3-1:5, the reaction temperature is controlled at 50-54° C., the reaction time is 48-50 hours, and the precipitate is washed repeatedly to obtain modified pullulan.

2. Dissolve the above-mentioned modified pullulan in anhydrous 1,4-dioxane to prepare a solution with a concentration of 10-20%, and add succinic anhydride, dimethylaminopyridine and triethylamine In the above solution, the weight ratio is 10-12:8-11:8-10, the weight ratio of its amount to pullulan is 1:1-1.2, react under nitrogen protection for 24-28 hours, and the resulting solution is rotated The 1,4-dioxane was removed by an evaporator, and the unreacted substances in the remaining liquid were removed with carbon tetrachloride. Concentrate the above solution to 100-150ml with a rotary evaporator, then put it into diethyl ether at 2-4°C for precipitation, and vacuum-dry the obtained precipitate at 30-40°C. The above precipitate and sulfidethoxine, carbonized bicyclohexyl imide and hydroxysuccinimide are added to anhydrous dimethyl sulfoxide in a weight ratio of 19-21:5-7:4-6:2-4 reaction at room temperature for 24 hours, the resulting reaction mixture was filtered to remove precipitates, the resulting solution was dialyzed for three days with distilled water, and then the resulting solution was subjected to three purification processes of freeze-drying-thawing-lyophilization to obtain the product, namely acetylated pullulan - Sulfadetoxine.

3. The preparation of drug-loaded nanoparticles, the modified pullulan-sulfidethoxine and 5-fluorouracil were dissolved in dimethyl sulfoxide, dialyzed in aqueous solution by dialysis, and the self-assembled carrier was obtained after removing the organic phase. drug nanohydrogel solution. The resulting solution was freeze-dried to obtain drug-loaded nanoparticle powder.

The advantage of the present invention is that the modified pullulan-sulfidethoxine can self-assemble in water to form nanoparticles with a stable core-shell structure, and 5-fluorouracil and hydrophobic acetyl groups can gather to form nuclei. - sulfidethoxine forms a hydrophilic shell, which greatly increases the solubility and bioavailability of 5-FU; and the grafted sulfidethoxine can make the drug-loaded nanoparticles prepared at pH=6.6-6.9 ( That is, near the pH value of tumor cell fluid), strongly aggregates and releases drugs, and realizes slow release and maintains particle size at pH=7.4 or above (that is, near the pH value of normal cell fluid); the nanocarrier has high drug encapsulation efficiency and large drug loading capacity , and its drug encapsulation rate is above 80%; the carrier prepared according to the present invention has high stability after freeze-drying into powder, and is easy to store, transport and apply; less toxic reagents are used when preparing the carrier, and the preparation process is simple; biodegradability and It has good bioavailability and is an ideal carrier for 5-fluorouracil.

Description of drawings

Figure 1 is a scanning electron micrograph of 5-fluorouracil-loaded nanoparticles prepared according to the method of Example 1.

Figure 2 is the in vitro release curves of 5-fluorouracil-loaded nanoparticles without modification of sulfidethoxine at different pH values.

Fig. 3 is the in vitro release curve of 5-fluorouracil-loaded nanoparticles modified by sulfidethoxine at different pH values.

Fig. 4 is a graph showing the relationship between changing the grafting amount of sulfidethoxine on the in vitro release of nanoparticles loaded with 5-fluorouracil at different pH values.

Detailed ways

Embodiment one:

1. Pullulan modification

Dissolve 2g of pullulan in 20ml of formamide solution, add 60ml of pyridine and 150ml of acetic anhydride into the solution, and react at 54°C for 48 hours. The resulting solution was reprecipitated in distilled water, washed and dried with methanol solution to obtain a white powder, that is, acetylated pullulan.

2. Graft Sulfadetoxine

2.1. Dissolve 5g of acetylated pullulan in 1,4-dioxane, and add 2.2g of succinic anhydride, 2.0g of dimethylaminopyridine, and 1.8g of triethylamine into the above solution, and then After reacting for 24 hours, the resulting solution was removed by a rotary evaporator to remove 1,4-dioxane, and 300 mL of carbon tetrachloride was used to remove unreacted succinic anhydride in the remaining liquid. The above solution was concentrated to 150 ml with a rotary evaporator, and then it was placed in diethyl ether at 4° C. for precipitation, and the resulting precipitate was vacuum-dried for 24 hours.

2.2. Add 1 g of the above precipitate, 300 mg of sulfidethoxine, 250 mg of carbonized bicyclohexyl imide, and 150 mg of hydroxysuccinimide to 40 mL of anhydrous dimethyl sulfoxide, and react at room temperature for 24 hours. The obtained reaction mixture was filtered to remove the precipitate, the obtained solution was dialyzed with distilled water for three days, and then the obtained solution was subjected to three freeze-drying-thawing-freeze-drying purification processes to obtain the product, ie, acetylated pullulan-sulfidethoxine.

3. Preparation of Loaded Nanoparticles

20mg of 5-fluorouracil and 50mg of acetylated pullulan-sulfidethoxine were dissolved in 20ml of dimethyl sulfoxide, and then the mixed solution was put into a dialysis bag with a cut-off molecular weight of 15000 for dialysis for three days, and the resulting The solution is filtered through a 0.45 μm filter membrane and freeze-dried to obtain the nanoparticle powder loaded with 5-fluorouracil. The average particle diameter of nanoparticles is 110nm, and the sphericity is good.

Embodiment two:

The acetylated pullulan and 5-fluorouracil prepared according to the first step method in Example 1 can be prepared according to the third step method in Example 1 to obtain the carrier 5 that has not been modified by the pH-sensitive group sulfidethoxine. - Fluorouracil nanoparticles, 20 mg of the above drug-loaded nanoparticles were subjected to an in vitro release test in buffer solutions of pH=6.0, 6.8, 7.4, and 8.2 at a temperature of 37° C., and the release curves are shown in FIG. 1 . It can be seen from Figure 1 that the total release of 5-fluorouracil at different pH values is roughly the same, with an average of 65% (18 hours). There is no obvious pH sensitivity, but a certain sustained release effect is achieved.

Embodiment three:

20 mg of drug-loaded nanoparticles prepared according to the method of Example 1 were subjected to in vitro release tests in buffer solutions of pH=6.0, 6.8, 7.4, and 8.2 at a temperature of 37° C., and the release curves are shown in FIG. 2 . As can be seen from Figure 2, the total release of 5-fluorouracil in 18 hours rose sharply from 62.92% of pH=8.2 and 69.94% of pH=7.4 to 80.72% of pH=6.8 and 83.12% of pH=6.0, showing great Strong pH sensitivity.

Embodiment four:

The amount of sulfidethoxine in the second step of Example 1 was increased to 500 mg, and drug-loaded nanoparticles with a higher grafted amount of sulfidethoxine could be prepared in the same manner. The above-mentioned drug-loaded nanoparticles were subjected to in vitro release tests at a temperature of 37° C. in different buffer solutions with pH=6.0, 6.8, 7.4, and 8.2. The release curves are shown in FIG. 3 . As can be seen from Fig. 3, with respect to the nanometer described in the example two, the drug-loaded nanoparticle that has increased the grafted amount of sulfidethoxine has higher drug release at pH=6.8 and 6.0, and at pH=7.4 and 8.0, the release amount was slightly reduced, and the drug-loaded nanoparticles showed stronger pH sensitivity than Example 2.

Claims (2)

1. responsive controllable release nanoparticle of pH that carries the 5-fluorouracil medicine; it is characterized in that this nanoparticle is the hud typed structure of particle diameter at 50-200nm; its shell material is modification Pullulan-sulfadimethoxine; its nuclear material is the acetyl group part of modification Pullulan; drug-carrying nanometer particle is in the strong gathering of pH=6.6-6.9 and discharge medicine; and more than pH=7.4, realize slow release and keep granularity that its entrapment efficiency is more than 80%.

2. method for preparing by the described nanoparticle of claim 1 is characterized in that comprising following process:

1). the Pullulan of molecular weight at 100000-200000 is dissolved in the formamide solution, be prepared into the solution that concentration is 10-15%, adding acetic anhydride in this solution carries out hydrophobically modified to Pullulan, the weight ratio of Pullulan and acetic anhydride is 1: 3-1: 5, reaction temperature is controlled at 50-54 ℃, response time 48-50 hour, the gained precipitation obtained the modification Pullulan behind cyclic washing;

2). above-mentioned modification Pullulan is dissolved in exsiccant 1, the 4-dioxane is prepared into the solution that concentration is 10-20%, and with succinic anhydride, dimethyl aminopyridine, triethylamine adds in the above-mentioned solution, its weight ratio is 10-12: 8-11: 8-10, its amount is 1 with the Pullulan weight ratio: 1-1.2, reaction is 24-28 hour under nitrogen protection, gained solution is removed 1 through Rotary Evaporators, the 4-dioxane, and with removing unreacted reactant in the raffinate in the carbon tetrachloride, above-mentioned solution is concentrated into 100-150ml with Rotary Evaporators, put it into then in 2-4 ℃ the ether and precipitate, gained is deposited in 30-40 ℃ of following vacuum drying, with above-mentioned precipitate and sulfadimethoxine, carbonization dicyclohexyl imines, N-Hydroxysuccinimide is that 19-21: 5-7: 4-6: 2-4 joins in the anhydrous dimethyl sulphoxide by its weight ratio, reaction is 24 hours under room temperature, the gained reactant mixture removes by filter precipitation, gained solution is through distill water dialysis three days, then gained solution obtained product after three lyophilizing-thaw-freeze dried purge process, i.e. acetylation Pullulan-sulfadimethoxine;

3). the preparation of drug-carrying nanometer particle, modification Pullulan-sulfadimethoxine and 5-fluorouracil are dissolved in dimethyl sulfoxide, dialyse in aqueous solution with dialysis, remove and obtain the medicament-carried nano hydrogel solution that self assembly forms after the organic facies, the lyophilization of gained solution is obtained the drug-carrying nanometer particle powder.

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