An emulsion gel capable of loading and delivering amphiphilic drugs, its preparation method and application

Abstract

This invention relates to the field of drug loading and delivery materials, and discloses an emulsion gel capable of loading and delivering amphiphilic drugs, its preparation method, and its application. The emulsion gel is formed by encapsulating an oil phase with ovalbumin as an emulsifier to form an emulsion. The stability of the emulsion is enhanced by adding Polygonatum sibiricum polysaccharide to facilitate its interaction with ovalbumin, and a stable gel structure is formed by gellan gum and the emulsion. The ovalbumin encapsulating the oil phase forms a core-shell structure, while the gellan gum and the emulsion form an interpenetrating network structure. The emulsion gel of this invention can gel at room temperature. Due to its mild gelation conditions, it can not only load most highly active but unstable amphiphilic drugs, but also effectively deliver heat-sensitive and acid-sensitive amphiphilic drugs.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drug loading delivery materials, in particular to an emulsion gel capable of loading and delivering amphiphilic drugs, a preparation method and application thereof. BACKGROUND

[0002] Emulsion gel is a kind of gel-like solid or semi-solid with the dual characteristics of emulsion and gel, which is formed by the continuous phase forming a space network structure and the dispersed phase filling, and the dispersed phase is embedded in the continuous phase, based on emulsion, and induced by different induction methods such as acid, alkali, salt, temperature and enzyme. The dispersed phase in the emulsion gel can be liquid or solid lipid particles. According to the influence of the dispersed phase on the characteristics of the gel, the dispersed phase can be divided into active fillers and non-active fillers. The active fillers can be connected to the gel network, which helps to enhance the gel strength. The non-active fillers have low chemical affinity to the gel matrix, and do not interact or interact with the gel matrix. According to the relative spatial distribution of the oil phase and the water phase, the emulsion gel can be divided into water-in-oil (W / O) type and oil-in-water (O / W) type. Compared with the W / O type emulsion gel, the O / W type emulsion gel is an ideal system for embedding, stabilizing and delivering lipid-soluble drugs. On the one hand, the inner oil phase containing lipophilic compounds is wrapped in the water phase, which inhibits the diffusion of lipid-soluble compounds through the bilayer oil-water interface to the outside of the system. On the other hand, the oil phase droplets are fixed in the network structure of the gel, preventing them from flocculating and aggregating.

[0003] Huangjing is a traditional Chinese medicinal material in China, which is the dry rhizome of Polygonatum kingianum, Polygonatum sibiricum or Polygonatum cyathopetalum. It is praised as "Xianren Yulang" due to its effects of invigorating the spleen, tonifying qi, benefiting the kidney and moistening the lung. Modern medicine shows that Huangjing contains rich polysaccharides, which have the effects of regulating human immunity, anti-aging, regulating blood sugar and blood lipid, and protecting nerves. Due to its complex biological structure and functional activity, it has become one of the research and development hotspots in the fields of food and medicine. Huangjing polysaccharide (PSP) is one of the most abundant active substances in Huangjing, and is the main functional active carrier.

[0004] Protein is the most widely used emulsifier in food-grade oil-in-water emulsion. It is known that the adsorption of protein at the oil-water interface can stabilize oil-in-water emulsion by reducing the interfacial tension and forming a viscoelastic layer at the interface. The optimal protein concentration for stable oil-in-water emulsion depends on the characteristics of the protein molecules such as isoelectric point, molecular weight, molecular structure and flexibility. Ovalbumin (OVA) as a kind of emulsifier with good biocompatibility can be well adsorbed on the oil-water interface through electrostatic interaction, thereby reducing the interfacial tension and forming a stable emulsion.

[0005] Gellan gum (GG) is a safe and non-toxic microbial exopolysaccharide, as a gelling agent, gellan gum has good stability, acid resistance, high temperature resistance, heat reversibility and low dosage characteristics; after gellan gum is dissolved in water, the molecules will automatically gather to form a double helix structure, the main force stabilizing the double helix structure is the intermolecular hydrogen bond, the double helix further gathers to form a three-dimensional network structure, which is convenient for trapping water molecules to produce gel phenomenon. The gel mechanism of gellan gum is considered to be the polymerization and crosslinking between double helixes induced by cations, which can promote intramolecular crosslinking, stabilize double helix structure and accelerate the formation of three-dimensional network structure by double helix. The carboxyl side chain of gellan gum molecules repels each other due to electrostatic interaction, which hinders the close aggregation of the helix, and the intervention of cations can shield the electrostatic repulsion. However, gellan gum has high brittleness and is affected by cation concentration, thereby limiting its application in food.

[0006] In summary, polysaccharides of rhizoma polygonati, ovalbumin and gellan gum have advantages and disadvantages in preparing emulsion gels; therefore, how to combine polysaccharides of rhizoma polygonati, ovalbumin and gellan gum to form an emulsion gel and use it to load and deliver amphiphilic unstable drugs is a technical problem to be solved by those skilled in the art. SUMMARY

[0007] Therefore, the purpose of the present application is to provide an emulsion gel capable of loading and delivering amphiphilic drugs, a preparation method and application, the prepared emulsion gel can be used to load and deliver amphiphilic unstable drugs, and can also complete the effective delivery of thermosensitive and acid-sensitive amphiphilic drugs.

[0008] The present application solves the above technical problems through the following technical means:

[0009] In a first aspect, the present application discloses an emulsion gel capable of loading and delivering amphiphilic unstable drugs, the raw materials of the emulsion gel include ovalbumin, oil phase material, polysaccharides of rhizoma polygonati and gellan gum.

[0010] Further, the emulsion gel is an emulsion formed by wrapping the oil phase with ovalbumin as an emulsifier, the stability of the emulsion is enhanced by adding polysaccharides of rhizoma polygonati to interact with ovalbumin, and a stable gel structure is formed by gellan gum and the emulsion.

[0011] Further, the oil phase material wrapped by the ovalbumin forms a core-shell structure, and the gellan gum and the emulsion form an interpenetrating network structure.

[0012] The emulsion gel can not only load most of the active two-phase drugs with unstable properties, but also complete the effective delivery of heat-sensitive and acid-sensitive two-phase drugs.

[0013] Further, the purity of the egg white protein is 66-88%, and the mass fraction of the egg white protein in the emulsion gel is 2.0-3.0%.

[0014] Further, the purity of the egg white protein is 66-88%, and the mass fraction of the egg white protein in the emulsion gel is 2.0-3.0%.

[0015] Further, the purity of the egg white protein is 66-88%, and the mass fraction of the egg white protein in the emulsion gel is 2.0-3.0%.

[0016] Further, the oil phase material is vegetable oil, including one or a combination of sunflower oil, peanut oil, soybean oil, and rapeseed oil.

[0017] In a second aspect, the present application also discloses a preparation method of an emulsion gel capable of loading and delivering two-phase unstable drugs, comprising the following steps:

[0018] S1, dissolve egg white protein in water, filter the egg white protein solution after stirring and dissolving, then take the oil phase and place it in the egg white protein solution, emulsify to obtain an emulsion;

[0019] S2, add polygonatum sibiricum polysaccharide to the emulsion to fully dissolve the polygonatum sibiricum polysaccharide to form an egg white protein-polygonatum sibiricum polysaccharide emulsion;

[0020] S3, take the gelling agent, add deionized water and stand to obtain a gelling agent solution, then solidify the gelling agent solution into a gel, heat the solidified gelling agent in a water bath to dissolve it into a liquid state;

[0021] S4, mix the gelling agent solution dissolved into a liquid state with the egg white protein-polygonatum sibiricum polysaccharide emulsion to obtain an emulsion gel preparation;

[0022] S5, store the emulsion gel preparation in a 2-6℃ environment to form a stable gel structure, i.e., an emulsion gel.

[0023] Further, in step S1, a homogenizer is used for emulsification treatment, and the emulsification conditions of the homogenizer are 8000-12000rmp and the emulsification time is 20-40s.

[0024] In a third aspect, the present application further discloses application of the emulsion gel to delivery of amphiphilic drugs, heat-sensitive drugs and acid-sensitive drugs.

[0025] The present application has the following advantages:

[0026] 1. The egg white protein-polysaccharide emulsion gel is a good unstable drug delivery carrier. Compared with other similar drug gel carriers, the emulsion gel can be gelled at room temperature under high-temperature, high-concentration metal salt or acidic and alkaline gel forming conditions. Since the gel forming conditions are mild, the emulsion gel can load most active but unstable amphiphilic drugs and complete effective delivery of heat-sensitive and acid-sensitive amphiphilic drugs.

[0027] 2. The egg white protein-polysaccharide emulsion gel has good biocompatibility. Since the materials used for preparing the gel are all natural biological materials, the drug carrier does not produce toxic side effects on the body.

[0028] 3. The polysaccharide added in the emulsion gel prepared in the present application has the functions of improving immunity and antioxidant; egg white protein, as a common nutrient, has the effects of improving immunity and supplementing nutrients required by the human body. Therefore, the emulsion gel is not only a biocompatible amphiphilic, heat-sensitive and acid-sensitive drug delivery carrier, but also a functional nutrient with antioxidant and immune regulation functions. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a structural schematic diagram of the emulsion gel of the present application;

[0030] Figure 2 is a diagram of the emulsion gel prepared in Example 1-Example 3 of the present application;

[0031] Figure 3 is a diagram of the influence of different contents of PSP, GG and OIL on the WHC of the gel;

[0032] Figure 4 is a diagram of the digestion rate of the emulsion gel prepared in Example 1-Example 3 of the present application in simulated gastric juice;

[0033] Figure 5 is a diagram of the digestion rate of the emulsion gel prepared in Example 1-Example 3 of the present application in simulated intestinal juice. DETAILED DESCRIPTION

[0034] The present application will be described in detail below with reference to the accompanying drawings:

[0035] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not critical to the properties. The endpoints of the ranges and any numerical values should be considered to be open-ended in the context of the ranges explicitly recited, for example, ranges of "from about 0.1% to about 10%" are considered to include, along with the endpoints, the exact weight amounts of "0.1%" and "10%," the exact length amounts of "0.1%" and "10%," and ranges of weights and lengths outside of the explicit recited ranges, for example, "from 0.05% to 10%," "from 0.5% to 15%," and so forth.

[0036] Example 1,

[0037] This example is the preparation of emulsion gel with different contents of polygonatum sibiricum polysaccharide, including the following steps:

[0038] First, prepare a 50mg / mL egg white protein solution, add sunflower oil, emulsify at 8000rpm using a homogenizer for 20s, add polygonatum sibiricum polysaccharide solid powder to the obtained emulsion, and vortex to dissolve completely; take a certain amount of emulsion with dissolved polygonatum sibiricum polysaccharide, add different contents of gellan gum hot solution, mix well, and stand for 12h to completely gel and keep the structure stable; the purity of egg white protein used in this example is 66%, the purity of polygonatum sibiricum polysaccharide is 70%, and the gellan gum is low-acyl gellan gum. The contents of various substances in the formed emulsion gel are shown in Table 1.

[0039] Table 1 Preparation ratio table of emulsion gel with different contents of polygonatum sibiricum polysaccharide

[0040]

[0041] Example 2,

[0042] This example is the preparation of emulsion gel with different contents of gellan gum, including the following steps:

[0043] First, prepare a 50mg / mL egg white protein solution, add sunflower oil, emulsify at 10000rpm using a homogenizer for 30s, add polygonatum sibiricum polysaccharide solid powder to the obtained emulsion, and vortex to dissolve completely; take a certain amount of emulsion with dissolved polygonatum sibiricum polysaccharide, add different contents of gellan gum hot solution, mix well, and stand for 12h to completely gel and keep the structure stable; the purity of egg white protein used in this example is 77%, the purity of polygonatum sibiricum polysaccharide is 75%, and the gellan gum is low-acyl gellan gum. The contents of various substances in the formed emulsion gel are shown in Table 2.

[0044] Table 2 Preparation ratio table of emulsion gel with different contents of gellan gum

[0045]

[0046] Example 3,

[0047] This example is the preparation of emulsion gel with different contents of oil, including the following steps:

[0048] First, 50 mg / mL of egg white solution was prepared, and different amounts of sunflower oil were added to the egg white solution. The mixture was emulsified at 12000 rpm for 40 s using a homogenizer. Solid polysaccharide from Polygonatum sibiricum was added to the obtained emulsion, and vortex shaking was performed to completely dissolve the polysaccharide. 2% of a hot solution of gellan gum was added to the emulsion in which the polysaccharide from Polygonatum sibiricum was dissolved, and the mixture was uniformly mixed and then left to stand for 12 h to completely form a gel and maintain a stable structure. The purity of the egg white used in this example was 88%, the purity of the polysaccharide from Polygonatum sibiricum was 80%, and the gellan gum used was low-acyl gellan gum. The contents of the substances in the formed emulsion gel are shown in Table 3.

[0049] Table 3 Preparation ratio table of emulsion gels with different oil contents

[0050]

[0051]

[0052] The emulsion gels prepared in Examples 1-3 above are shown in Table 4, wherein the contents of polysaccharide, gellan gum, and oil phase from left to right in (a), (b), and (c) increase according to Tables 1-3. Figure 2

[0053] In addition, in order to make a unified comparison, the sunflower oil used in Examples 1-3 above is used in actual use. Peanut oil, soybean oil, rapeseed oil, etc. can also be used, and combinations thereof can also be used.

[0054] Example 4,

[0055] In this example, the centrifugal water holding rate (WHC) of the emulsion gels prepared in Examples 1-3 was determined. The determination method includes the following steps:

[0056] 0.5 g of the gel sample of Examples 1-3 was added to a 2 mL ultrafiltration tube (MWCO = 100 kDa), and centrifugation was performed at 8000 rpm for 10 min. The water in the centrifuge tube was removed. The WHC was calculated as follows:

[0057] WHC (%) = (M2-M1) / (M3-M1) x 100%

[0058] Wherein: M1 is the weight of the centrifuge tube; M2 is the total weight of the sample and the centrifuge tube after removing the water; and M3 is the total weight of the original sample and the centrifuge tube.

[0059] ​During the gelation of emulsion, the stable three-dimensional network structure formed between the molecules of gellan gum can retain free water, so that the emulsion gel has a certain water holding capacity. The centrifugal water holding rate of the gel reflects the strength of the gel and the stability after loading drugs as a drug carrier. The ability to effectively fix the water in the gel network is an important property of good gel. In general, the hardness and stability of the gel are positively correlated with the centrifugal water holding rate. As shown in Figures 3-4 With the increase of the content of polygonatum sibiricum and gellan gum in the emulsion gel, the centrifugal water holding rate of the gel increased significantly. This is because when the emulsion forms a gel, the polygonatum sibiricum particles solidified in the three-dimensional network structure of the gel act as active filler, and polygonatum sibiricum forms stable hydrogen bonds by interacting with ovalbumin, making the structure of the gel more stable; with the increase of the content of gellan gum, the centrifugal water holding rate of the emulsion gel also shows a significant growth trend. This is because gellan gum plays the role of gelling agent in the emulsion gel, and when the content of gellan gum in the emulsion gel increases, the two-dimensional spiral structure formed by the dissolution of gellan gum in water has a higher density, and then it is easier to form a three-dimensional network structure, at the same time, the network structure formed is also more dense, the more ordered the network structure, the worse the water flowability and flexibility, so it shows a higher centrifugal water holding rate; the oil phase in the gel is sunflower oil, when the oil phase concentration is low, ovalbumin is effectively adsorbed and gathered on the surface of the lipid particle during the emulsification process, thereby forming an interface protein film around it. This film stabilizes the lipid particles, prevents the aggregation of lipid particles, and at the same time hydrates with water molecules, thereby enhancing the protein crosslinking system, so that water is wrapped in the gel matrix. Under the same emulsification conditions, the increase of the emulsified lipid concentration, i.e. the increase of the lipid particles greatly promotes the crosslinking between protein molecules, and the centrifugal water holding rate of the gel will be improved to a certain extent. However, this linear relationship is limited, when a large number of lipid particles exist in the gel, the lipid particles will inevitably aggregate and form larger cavities in the gel network structure, which causes a certain damage to the protein network structure, and the water holding capacity of the gel decreases sharply.

[0060] Example 5,

[0061] This example is to determine the digestion rate of the O / W emulsion gel prepared in examples 1-3 which can load and deliver amphiphilic unstable drugs in gastric juice, including the following steps:

[0062] Since the egg white protein will be enzymatic hydrolysis under the action of pepsin, generate a variety of small molecule amino acids, and tyrosine and tryptophan have the maximum absorption peak at 280 nm. Therefore, 0.5 g of the gel sample of Example 1-3 was dispersed in 4.5 mL of HCl (pH = 1.5) and 15 mg of pepsin, and simulated gastric peristalsis was carried out at 37°C under the condition of 140 rpm for 2 h. After the enzymatic hydrolysis was completed, the enzyme activity was inactivated in a 90°C water bath for 10 min, and finally centrifuged at 8000 rpm for 10 min. The OD 280 nm .

[0063] Figure 4 (Note: from left to right PSP: 0, 0.5, 1.0, 1.5, 2.0%; GG: 0.6, 0.8, 1.0, 1.2, 1.4%; OIL: 1.0, 2.0, 3.0, 4.0, 5.0%) After 2 h of simulated gastric juice digestion, the gel state can be clearly seen. The emulsion gel prepared under any condition was found to have no obvious degradation phenomenon. The simulated gastric juice of the inactivated gel was centrifuged, and the supernatant was measured for absorbance. It was found that the absorbance of the simulated gastric juice at OD 280 nm The absorbance of the simulated gastric juice at OD

[0064] Example 6,

[0065] This example is the determination of the digestion rate of the O / W emulsion gel prepared in Examples 1-3 which can load and deliver amphiphilic unstable drugs in intestinal juice, including the following steps:

[0066] After the gel was taken out from the simulated gastric juice, 5 mL of 0.5 mol / L KH2PO4 was added and adjusted to pH 8 with NaOH, and 10 mg of trypsin was added. After 4 h of simulated intestinal peristalsis at 37°C under the condition of 140 rpm, the enzyme activity was inactivated in a 90°C water bath for 10 min, and finally centrifuged at 8000 rpm for 10 min. The OD 280 nm .

[0067] Figure 5(Note: from left to right PSP: 0, 0.5, 1.0, 1.5, 2.0%; GG: 0.6, 0.8, 1.0, 1.2, 1.4%; OIL: 1.0, 2.0, 3.0, 4.0, 5.0%) are the gel states after 4h digestion in simulated intestinal fluid. The simulated fluid after 4h digestion of the gel was removed, and the supernatant was taken after centrifugation to measure the absorbance. It was found that the absorbance at OD 280 nm The absorbance in the simulated intestinal fluid was much greater than that in the simulated gastric fluid, which proved that the O / W emulsion gel of the application capable of loading and delivering an amphiphilic unstable drug can be fully degraded in the intestinal tract to release the drug embedded therein. In particular, it was found that Figure 5 It can be seen that the digestibility of the emulsion gel of the application in the intestinal tract decreases with the increase of the contents of the rhizoma polygonati polysaccharide and the gellan gum, which indicates that with the increase of the contents of the rhizoma polygonati polysaccharide and the gellan gum, the structure of the emulsion gel is more stable, the electrostatic interaction, hydrophobic interaction and hydrogen bond force are stronger, and it is more conducive to the formation of a dense three-dimensional network structure of the gel. With the increase of the content of the oil phase, the digestibility of the gel in the intestinal fluid first decreases and then increases, which is because when the oil phase in the emulsion gel increases within a certain range, the oil particles in the gel act as active filler materials of the gel, the oil particles are filled into the pore structure of the gel to make the gel structure more dense, which is not conducive to the infiltration of the simulated intestinal fluid into the interior of the gel to cause the decrease of the digestibility. When the content of the oil phase in the gel exceeds a certain range, the oil phase particles in the gel will inevitably aggregate to a certain extent, and greatly reduce the surface tension of the gel, so that the texture of the whole gel becomes loose, which is conducive to the infiltration of the digestive fluid into the interior of the gel, so that the digestibility of the gel is significantly improved.

[0068] It can be seen from Examples 1-6 that the emulsion gel of the application has good structural stability, can stably exist under the strong acidic conditions of the gastric fluid, and can ensure its stable degradation in the weak alkaline environment of the intestinal fluid to release the drug embedded therein. At the same time, it can be seen from Examples 1-6 that the mechanical strength and drug release of the gel can be regulated by adjusting the contents of PSP, GG and OIL, such as increasing or decreasing the contents of PSP, GG or OIL to increase or decrease the hardness of the gel and the digestibility in the gastrointestinal tract.

[0069] The above examples are only used to illustrate the technical solutions of the application but not limit the application. Although the application has been described in detail with reference to the preferred embodiments, it will be apparent to those skilled in the art that the technical solutions of the application can be modified or equivalently replaced without departing from the spirit and scope of the application, which should be covered by the scope of the claims of the application. The technical, shape and structure parts not described in detail in the application are well-known technologies.

Claims

1. An emulsion gel loadable to deliver an amphiphilic drug, characterized in that: The raw materials of the emulsion gel include egg white, oil phase material, polygonatum sibiricum polysaccharide and gellan gum; the emulsion gel is formed by wrapping the oil phase with egg white as an emulsifying agent to form an emulsion, then adding polygonatum sibiricum polysaccharide to the emulsion to interact with the egg white to enhance the stability of the emulsion, and finally adding gellan gum to form a stable gel structure with the emulsion; the oil phase material wrapped by the egg white forms a core-shell structure, and the gellan gum and the emulsion form an interpenetrating network structure.

2. The emulsion gel according to claim 1, wherein: The purity of the egg white is 66-88%, and the mass fraction of the egg white in the emulsion gel is 2.0-3.0%.

3. The emulsion gel of claim 1, wherein: The purity of the polygonatum sibiricum polysaccharide is 70-80%, and the mass fraction of the polygonatum sibiricum polysaccharide in the emulsion gel is 0.5-2.0%.

4. The emulsion gel of claim 1, wherein: The gellan gum is low-acyl gellan gum, and the mass fraction of the gellan gum in the emulsion gel is 0.6-1.4%.

5. The emulsion gel of claim 1, wherein: The oil phase material is vegetable oil, including one or a combination of sunflower oil, peanut oil, soybean oil and rapeseed oil.

6. A method of preparing an emulsion gel loadable to deliver an amphiphilic drug, characterized by: The steps include: S1, dissolve egg white in water, filter the egg white solution after stirring and dissolving, then take the oil phase and place it in the egg white solution, emulsify to obtain an emulsion; S2, add polygonatum sibiricum polysaccharide to the emulsion to fully dissolve the polygonatum sibiricum polysaccharide to form an egg white-polygonatum sibiricum polysaccharide emulsion; S3, take gellan gum, add deionized water and stand to obtain a gellan gum solution, then solidify the gellan gum solution into a gel, heat the solidified gellan gum in a water bath to dissolve it into a liquid state; S4, mix the gellan gum solution dissolved into a liquid state with the egg white-polygonatum sibiricum polysaccharide emulsion to obtain an emulsion gel preparation; S5, store the emulsion gel preparation in a 2-6℃ environment to form a stable gel structure, i.e. an emulsion gel.

7. A method of preparing an emulsion gel loadable to deliver an amphiphilic drug according to claim 6, characterized in that: In step S1, a homogenizer is used for emulsification, and the emulsification conditions of the homogenizer are 8000-12000rmp and the emulsification time is 20-40s.

8. Use of the emulsion gel of claim 1 in the preparation of a carrier for delivering amphiphilic drugs, heat-sensitive and acid-sensitive drugs.

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