CN101167706A - The synthetic method of chitosan nano microcapsule - Google Patents

Abstract

The synthesis method of chitosan nano-microcapsules can be widely used as drug carriers or biomedical materials. The preparation steps are: a. preparing a water-in-oil type inverse microemulsion system solution by a conventional method; b. adding chitosan or chitosan derivatives dropwise to the microemulsion system, using the interface that the microemulsion system itself has Can disperse; c. add cross-linking agent TPP, chitosan or chitosan derivatives and cross-linking agent TPP in the microemulsion system solution automatically attract and polymerize into capsules through positive and negative charges; d. centrifuge the solution in step c processing, discarding the supernatant to obtain chitosan/TPP nanocapsules or chitosan derivatives/TPP nanocapsules, and finally washing and preserving the nanocapsules with absolute ethanol. The invention avoids the adverse effect of the capsule materials used in the existing nanometer microcapsules, has good biocompatibility, is easy to degrade, is low in price, has wide sources of chitosan and TPP, is simple and rapid in operation, and has good capsule forming effect.

Description

The synthetic method of chitosan nano microcapsule

technical field

The invention can be widely used as a drug carrier or a biomedical material, and belongs to the technical field of preparation of nanometer microcapsules.

Background technique

Biological microcapsules refer to microcapsules in which living tissues or cells are fixed with a semipermeable film. Since the semipermeable microcapsule membrane acts as a cell membrane, the shape and function of the microcapsules resemble cells, so it is also called " artificial cells". Material is one of the key factors determining the performance of microcapsules. It is generally required that its film-forming performance is good, it does not react with the encapsulated substance, and it should have certain mechanical strength and stability; for microcapsules used in biological environments, the material should also have good biocompatibility; in some cases Under the circumstances (such as controlled release of drugs), it needs to be biodegradable. The microcapsule materials used in current research reports mainly include natural, semi-synthetic and synthetic polymer materials. Some capsule materials often have some disadvantages such as certain toxicity or high viscosity or easy hydrolysis due to high solubility after salt formation, so they are not suitable for high temperature treatment or the products for clinical use are very limited. At present, biodegradable and bioabsorbable materials are widely valued and widely used. The preparation methods of biological microcapsules can be further divided into physical methods, chemical methods, and physicochemical methods, some of which are difficult to realize or inconvenient to operate. Therefore, the selection of capsule material and the design of preparation method are of great significance to the particle size, drug loading, sustained release performance, biocompatibility and other properties of biomicrocapsules.

The problems existing in the research of the current prescription process are mainly reflected in:

(1) Selection of capsule material: The impact of capsule material on biocompatibility, drug loading rate, and degradability is very important. At present, the pure natural material with good biocompatibility and degradable as capsule material has been a research hotspot. Chitosan and its derivatives have long been favored carrier materials, because they can be decomposed by lysozyme in the human body, and the decomposition products will not bring any harm to human health. This is a synthetic polymer and some natural polymers. incomparable. In the past two years, the various advantages of chitosan oligosaccharides and their advantages in food manufacturing, bioengineering, medical and health fields have become increasingly significant.

(2) Selection of preparation method: the preparation methods of biological microcapsules include chemical method (interface polymerization method, emulsification method, microemulsion method), physical method (air suspension method, electrostatic deposition method, mechanical method), physical and chemical method ( Phase separation method, solvent evaporation method, interface deposition method, spray drying method). Although the mechanical method in the physical method has certain applications in the preparation of capsules such as lipid particles, it is difficult to popularize and use because it requires special equipment. Although emulsion polymerization is widely used as an effective means of organic-inorganic particle combination and organic coating, it also has great limitations. Recently, with the improvement of domestic research level, microemulsion polymerization is easy to operate and the system Stable and uniform particle size has gradually become a research hotspot. Microemulsion is a thermodynamically stable, isotropic, transparent or translucent dispersion system formed by two immiscible liquids. The microemulsion polymerization method is not only widely used in daily chemical industry and tertiary oil recovery, but also in biochemical reactions, drug synthesis and nanomaterial preparation. Because different microemulsion systems can solubilize a large amount of hydrophilic or lipophilic substances, and can change the composition of the oil-water interface film by adjusting the composition, temperature, salinity and oil-water ratio, thereby changing the amount of solubilization and sustained release, etc., so In recent years, microemulsion systems have attracted extensive attention as drug carriers. The capsule formed by the microemulsion polymerization method has the advantages of good capsule shape, stable conditions, easy control, and easy operation of the preparation method.

Contents of the invention

Technical problem: the technical problem to be solved in this invention is to provide a kind of synthetic method of chitosan nano-microcapsules, aiming at the poor biocompatibility existing in the preparation of biological microcapsules in the past, not easy to degrade in the body and the preparation method is loaded down with trivial details, actual operating conditions and the dosage of medicines are difficult to grasp in the preparation process of biological microcapsules. The present invention selects chitosan and its derivatives, which are naturally easy to degrade and have good biological safety, as capsule materials, and use TPP as a cross-linking agent in the microemulsion system. Capsules are polymerized by electrostatic action, the method is simple and easy to operate, and the product is well encapsulated, safe and easy to degrade.

Technical scheme: the present invention uses chitosan (CS) and sodium tripolyphosphate (TPP) as raw materials, utilizes W/O inverse microemulsion system, and refers to literature (Ting Wang, Zhangqi Feng, Nongyue He, A NovelPreparation of Nanocapsules from Alginate-Oligochitosan, Journal of Nanoscience and Nanotechnology) established the best composition point of chitosan and sodium alginate in the inverse microemulsion system, and established the microemulsion system (oil phase, surfactant, co-surfactant three The optimum volume ratio is 64:12:9). Nanocapsules were prepared in the same system with the chitosan oligosaccharide without TPP and sodium alginate as the control, and the morphology of the capsules was observed and the average particle size was measured using transmission electron microscopy and scanning electron microscopy. It is found that the complexation with TPP has the advantages of good capsule shape, simple and fast preparation method and the like.

The technical solution of the present invention is:

a. Prepare water-in-oil type inverse microemulsion system solution by conventional method;

b. drop chitosan or chitosan derivatives in the microemulsion system, and disperse with the interfacial energy that the microemulsion system itself has;

c. Add cross-linking agent TPP, in the microemulsion system solution, chitosan or chitosan derivatives and cross-linking agent TPP automatically attract and polymerize into capsules through positive and negative charges;

d. Centrifuge the solution in step c, discard the supernatant to obtain chitosan/TPP nanocapsules or chitosan derivatives/TPP nanocapsules, and finally wash and preserve the nanocapsules with absolute ethanol.

In the water-in-oil type reverse microemulsion system solution, the oil phase is: one of castor oil, soybean oil, sesame oil, liquid paraffin, white vaseline, lanolin, cetyl alcohol, stearyl alcohol, and cyclohexane , the surfactant is: one of AOT [2-ethylhexyl], AOS, sodium lauryl sulfate, sodium hexadecyl sulfate, n-pentyl alcohol, and cetyltrimethylammonium bromide , Co-surfactant: octylphenyl polyoxyethylene ether (Triton-100). Referring to Document 1 (Ting Wang, Zhangqi Feng, Nongyue He, A Novel Preparation of Nanocapsules from Alginate-Oligochitosan, Journal of Nanoscience and Nanotechnology), the microemulsion system required for the preparation of nanoparticles can be obtained by mixing the three. The volume ratio of the oil phase, surfactant and co-surfactant is 64:12:9.

Beneficial effects: in the process of preparing biological microcapsules, the present invention selects natural and non-irritating natural capsule materials such as chitosan and its derivatives, TPP, and utilizes the principle of microemulsion system and macromolecular self-assembly, through both For the characteristics of polyelectrolyte complex materials, the two are complexed into capsules through charge attraction. And refer to the microemulsion environment determined in the article. Chitosan is the product of deacetylation of chitin. It has a structure similar to mucopolysaccharide. It is non-toxic and bioabsorbable, and its decomposition products will not cause biological tissue disorders. It has a wide range of sources, so it has shown its superiority in cell culture, microbial culture and pharmaceutical industry. The primary and secondary hydroxyl groups and amino groups of this cationic polymer make it react with acid and dissolve, so that the drug permeability is greater in acidic environment than in alkaline environment. Therefore, the controlled release of chitosan has certain targeting. Chitosan-based materials also form colloids in an acidic environment, which in turn reduces drug irritation to tissues and facilitates sustained release. Chitosan also has many biological activities beneficial to the human body, such as anti-tumor effect, immune adjuvant effect, promotion of tissue repair and hemostasis. Different types of microcapsules can be prepared by using the cationic properties of chitosan and the automatic polymerization of charged negative ions; more prominently, chitosan derivatives and chitosan degradation products are promising development directions as carriers. Sodium tripolyphosphate (TPP) has a wide range of sources, low price, and good biocompatibility. It can polymerize with chitosan to form capsules by virtue of the electrostatic interaction between the two.

Description of drawings

Fig. 1 is the synthesizing schematic diagram of chitosan/TPP nano nano microcapsule;

Fig. 2 is the transmission electron micrograph of the nano-microcapsule without adding TPP respectively;

Figure 3 is the scanning electron micrographs of the nano-microcapsules after adding TPP, respectively.

Detailed ways

The solution concentration is 1% (w/t) to 10% (w/t) chitosan oligosaccharide aqueous solution, the solution concentration is 0.5% (w/t) to 5% (w/t) TPP, and the microemulsion system as a reaction environment, in which the oil phase commonly used in the microemulsion system is castor oil, soybean oil, sesame oil, liquid paraffin, white petrolatum, lanolin, cetyl alcohol, stearyl alcohol, cyclohexane, etc., and the commonly used surfactants are AOT[ 2-Ethylhexyl], AOS, SDS (Sodium Dodecyl Sulfate), SDBS (Sodium Hexadecyl Sulfate), n-Pentyl Alcohol, CTAB (Cetyl Trimethyl Ammonium Bromide), etc. Surfactant can choose Triton-100 (polyoxyethylene ether), OP and so on. The volume percentage of each component of the microemulsion system is 64:12:9. The present invention adopts the microemulsion method to prepare nanoparticles, and uses chitosan+sodium alginate self-assembled and polymerized capsules as a control system to prepare a series of chitosan+TPP, TPP+chitosan+sodium alginate, etc., using TPP as a cross-linking agent. Oligochitosan is the biological microcapsule of capsule material. Scanning electron microscope and transmission electron microscope observation and comparison confirmed that the nano-particles added with TPP had a good encapsulation effect and the particles were dispersed.

1. Preparation of nanoparticles

Embodiment 1: chitosan oligosaccharide+sodium alginate+microemulsion system (control system)

In the oil phase castor oil, soybean oil, sesame oil, liquid paraffin, white petrolatum, lanolin, cetyl alcohol, stearyl alcohol, cyclohexane, etc., use cyclohexane; surfactants AOT [2-ethylhexyl, AOS, SDS (Sodium lauryl sulfate, SDBS (sodium cetyl sulfonate, n-pentanol, CTAB (cetyltrimethylammonium bromide) etc.) use n-pentanol; Co-surfactant selects octylbenzene Based polyoxyethylene ether (Triton-100). Triton-100, n-pentanol, and cyclohexane form a microemulsion system.

Referring to article 1, the three are added according to the oil phase, surfactant, and co-surfactant in a volume ratio of 64:12:9 for the oil phase, and a transparent microemulsion system is obtained. Chitooligosaccharide is dissolved in distilled water and is made into the solution 5 milliliters of the chitosan oligosaccharide of concentration about 2%, then slowly adds about 2% sodium alginate solution 5 milliliters. Stir at a speed of not less than 1000 rpm for about 10 minutes, wash with absolute ethanol and centrifuge at 10,000 rpm for 10 minutes, then wash twice with absolute ethanol and discard the supernatant to obtain nanocapsules as shown in Figure 2 shown.

Embodiment 2: chitosan oligosaccharide+TPP+microemulsion system

In the oily base agent castor oil, soybean oil, sesame oil, liquid paraffin, white vaseline, lanolin, cetyl alcohol, stearyl alcohol, cyclohexane, etc., choose stearyl alcohol, surfactant AOT [2-ethylhexyl], SDS is selected among AOS, SDS (sodium dodecyl sulfate), SDBS (sodium cetyl sulfonate), n-pentanol, CTAB (cetyltrimethylammonium bromide), etc.; co-surfactant selection Octylphenyl polyoxyethylene ether (Triton-100).

With octadecyl alcohol, SDS (stearyl alcohol: SDS=60: 12) as organic solvent, add about 9 milliliters of cosurfactant Triton-100, obtain transparent microemulsion system, dissolve chitosan oligosaccharide in distilled water and prepare Become the solution of the chitosan oligosaccharide of concentration about 8%, slowly add about 5 milliliters of the TPP solution of about 5%. Stir at a speed of not less than 1000 rpm/sec for about 10 minutes, wash with absolute ethanol and centrifuge at 10,000 rpm/second for 10 minutes, then wash twice with absolute ethanol to obtain nano-nano microcapsules as shown in Figure 3, and the embodiment 1 (Figure 2) Compared with this type of microcapsules, it is not easy to agglomerate into cysts and is better.

Embodiment 3: carboxymethyl chitosan+TPP+microemulsion system

In the oily base agent castor oil, soybean oil, sesame oil, liquid paraffin, white vaseline, lanolin, cetyl alcohol, stearyl alcohol, cyclohexane, etc., choose stearyl alcohol, surfactant AOT [2-ethylhexyl], SDS is selected among AOS, SDS (sodium dodecyl sulfate), SDBS (sodium cetyl sulfonate), n-pentanol, CTAB (cetyltrimethylammonium bromide), etc.; co-surfactant selection Octylphenyl polyoxyethylene ether (Triton-100).

Take stearyl alcohol, SDS (stearyl alcohol: SDS=64: 12) as organic solvent, add the cosurfactant Triton-100 of about 9 milliliters, obtain transparent microemulsion system, dissolve carboxymethyl chitosan in Make the solution of the chitosan oligosaccharide of concentration about 8% in distilled water, slowly add about 5 milliliters of the TPP solution of about 3%. Stir at a speed not lower than 1000 rpm for about 10 minutes, wash with absolute ethanol, centrifuge at 10,000 rpm for 10 minutes, and wash twice with absolute ethanol to obtain nanocapsules.

Embodiment 4: oligomeric glucosamine+TPP+microemulsion system

Cyclohexane is used in oily bases such as castor oil, soybean oil, sesame oil, liquid paraffin, white petrolatum, lanolin, cetyl alcohol, stearyl alcohol, cyclohexane, etc.; surfactants AOT [2-ethylhexyl], AOS , SDS (sodium dodecyl sulfate), SDBS (sodium hexadecyl sulfonate), n-pentanol, CTAB (cetyltrimethylammonium bromide), etc.; co-surfactant Use octylphenyl polyoxyethylene ether (Triton-100).

With n-pentanol, cyclohexane (n-pentanol: cyclohexane=64: 12) as organic solvent, add the cosurfactant Triton-100 of about 9 milliliters, obtain transparent microemulsion system, oligomeric glucosamine Dissolve in distilled water to make a glucosamine oligosaccharide solution with a concentration of about 1%, and slowly add about 5 ml of a 0.5% TPP solution. Stir at a speed not lower than 1000 rpm for about 10 minutes, wash with absolute ethanol, centrifuge at 10,000 rpm for 10 minutes, and wash twice with absolute ethanol to obtain nanocapsules.

Embodiment 5: chitosan oligosaccharide+sodium alginate+TPP+microemulsion system

Cyclohexane is used in oily bases such as castor oil, soybean oil, sesame oil, liquid paraffin, white petrolatum, lanolin, cetyl alcohol, stearyl alcohol, cyclohexane, etc.; surfactants AOT [2-ethylhexyl], AOS , SDS (sodium dodecyl sulfate), SDBS (sodium hexadecyl sulfonate), n-pentanol, CTAB (cetyltrimethylammonium bromide), etc.; co-surfactant Use octylphenyl polyoxyethylene ether (Triton-100).

With n-pentanol and cyclohexane (n-pentanol:cyclohexane=64:12) as the organic solvent, add about 9 ml of co-surfactant Triton-100 to obtain a transparent microemulsion system, add 10% seaweed 5 milliliters of the solution of sodium bicarbonate, slowly add about 5 milliliters of about 10% chitosan oligosaccharide solution, finally slowly add 5 milliliters of 5% TPP solution. Stir at a speed not lower than 1000 rpm for about 10 minutes, wash with absolute ethanol, centrifuge at 10,000 rpm for 10 minutes, wash twice with absolute ethanol and discard the supernatant to obtain nanocapsules.

Claims (3)

1. A chitosan nano mcirocapsule synthetic method, it is characterized in that preparation process is:

   A. adopt conventional method to prepare water-in-oil type reverse microemulsion system solution;

   B. drip chitosan or chitosan derivatives in described microemulsion system, the interface energy that has with microemulsion system itself disperses;

   C. add cross-linking agent TPP, chitosan or chitosan derivatives and cross-linking agent TPP attract the polymerization encystation automatically by positive and negative charge in microemulsion system solution;

   D. solution among the step c is carried out centrifugal treating, abandoning supernatant just obtains chitosan/sodium tripolyphosphate capsule of nano or chitosan derivatives/sodium tripolyphosphate capsule of nano, at last capsule of nano is preserved with absolute ethanol washing.
2. Chitosan nano mcirocapsule according to claim 1 synthetic method, it is characterized in that in the described water-in-oil type reverse microemulsion system solution, oil phase is: Oleum Ricini, Oleum Glycines, Oleum sesami, liquid paraffin, white vaseline, lanoline, hexadecanol, octadecanol, a kind of in the cyclohexane extraction, surfactant is: AOT[2 one ethylhexyl], AOS, sodium lauryl sulphate, sodium cetanesulfonate, n-amyl alcohol, a kind of in the cetyl trimethyl ammonium bromide, cosurfactant is the octyl phenyl polyoxyethylene ether, the three is mixed promptly obtaining preparing the needed microemulsion system of nano-particle.
3. Chitosan nano mcirocapsule according to claim 2 synthetic method, it is characterized in that described oil phase, surfactant, cosurfactant three volume ratio is 64: 12: 9.

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