Oral care composition and preparation method thereof

Abstract

The invention relates to the technical field of oral cavity compositions, and discloses an oral cavity nursing composition and a preparation method thereof.The preparation method comprises the steps that S1, green tea polyphenol, lactoferrin and grapefruit seed extract are dissolved in water according to the mass ratio of 1: 1: 1 and compounded with beta-cyclodextrin and chitosan to form an embedding system, and spray drying is conducted to prepare bacteriostatic microcapsules; s2, dispersing nano-hydroxyapatite in a glycerin-water mixed solution, adding sodium fluoride and calcium lactate, adjusting the pH value, and filtering to obtain a repair solution; s3, mixing eudesmol, spearmint oil and alpha-tocopherol to obtain a fragrant oil phase; s4, preparing a water-phase gel, adding the repairing liquid and the oil phase, emulsifying, and adding the micro-capsule to obtain a composite emulsion; and S5, adding a disodium hydrogen phosphate-citric acid buffer solution, and adjusting the pH value to 6.8-7.2 to obtain a finished product. The long-acting release and physical and chemical stability of the oral care composition in the aspects of bacteriostasis, repair and fragrance are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of oral compositions, and in particular to an oral care composition and a preparation method thereof. Background Art

[0002] Currently, a wide variety of oral care compositions are available on the market, including toothpastes, mouthwashes, oral sprays, and restorative gels. These primarily achieve their basic functions of cleaning, inhibiting bacteria, preventing caries, or improving breath quality by adding ingredients such as antibacterial agents, abrasives, aromatic extracts, and inorganic minerals. In recent years, some products have experimented with incorporating active ingredients such as nanohydroxyapatite, natural plant polyphenols, and lactoferrin to enhance enamel repair and biosafety, while also improving user experience through the use of flavor-modified or sustained-release particles.

[0003] However, when integrating multiple active ingredients into a single system, existing technologies generally face the problem of poor physical and chemical stability between functional components. For example, in a composite system containing plant extracts, mineral repair factors, and aromatic oils, complexation, precipitation, oxidation, or disintegration of the coating structure may occur between the components, resulting in a decrease in key functional activity or a shortened shelf life of the formulation, making it difficult to meet the dual requirements of long-term antibacterial and stable repair. Summary of the Invention

[0004] In view of this, the present invention provides an oral care composition and a preparation method thereof, aiming to solve the above problems.

[0005] In one aspect, the present invention provides a method for preparing an oral care composition, comprising the following steps:

[0006] S1: Preparation of composite antibacterial microcapsules, including:

[0007] Dissolve green tea polyphenols, lactoferrin, and grapefruit seed extract in deionized water at a mass ratio of 1:1:1, and adjust the pH to 5.0 to obtain an active ingredient solution;

[0008] β-cyclodextrin and chitosan were mixed in a mass ratio of 5:2 and dissolved in 60°C hot water to obtain a microcapsule wall material solution;

[0009] Add the active ingredient solution dropwise to the microcapsule wall material solution and stir to form an embedding dispersion system;

[0010] The dispersed system is spray-dried at an air inlet temperature of 140° C. and an air outlet temperature of 75° C. to obtain composite antibacterial microcapsules;

[0011] S2: preparing nano-hydroxyapatite repair solution, including:

[0012] Nanohydroxyapatite was ultrasonically dispersed in a mixture of glycerol and deionized water at a volume ratio of 1:4 at a mass concentration of 2 wt%.

[0013] Adding 1 wt % sodium fluoride solution and 0.5 wt % calcium lactate to the dispersion, adjusting the pH to 6.8, stirring evenly, and filtering through a 0.45 μm filter membrane to obtain a nano-hydroxyapatite repair solution;

[0014] S3: preparing a plant alcohol fragrance oil phase, comprising:

[0015] Eucalyptus globulus and spearmint oil were mixed in a volume ratio of 3:2, and 0.1 wt % of α-tocopherol was added and stirred to obtain an oil phase fragrance liquid;

[0016] S4: preparing a main agent of the composition, including:

[0017] Deionized water was used as solvent, 0.5 wt% carbomer, 20 wt% glycerol, 1 wt% Tween 80 and 0.3 wt% triethanolamine were added and stirred evenly, and the pH was adjusted to 6.5 to obtain a basic aqueous gel;

[0018] The repair liquid and the oil phase fragrance liquid were added to the basic aqueous phase gel at a volume ratio of 4:1, and high shear emulsification was performed at 8000 rpm for 3 minutes to form a W / O type composite emulsion;

[0019] Slowly adding the composite antibacterial microcapsule powder to the W / O type composite emulsion and stirring evenly to form a combined system;

[0020] S5: Adjust the pH buffer system, including:

[0021] A buffer solution consisting of disodium hydrogen phosphate and citric acid is added to the combined system to adjust the pH to 6.8-7.2 to obtain the oral care composition.

[0022] Preferably, the average particle size of the composite antibacterial microcapsules in step S1 is 80-120 μm, and the microcapsule coverage rate is ≥85%.

[0023] Preferably, the particle size of the nano-hydroxyapatite in step S2 is 30-60 nm, and the ultrasonic treatment power is 100 W, the frequency is 40 kHz, and the time is 10 minutes.

[0024] Preferably, the combined volume fraction of eucalyptol and spearmint oil in step S3 accounts for 10-15 wt % of the total mass of the composition.

[0025] Preferably, in step S4, the particle size of the water phase of the W / O type composite emulsion is 0.5-1.5 μm.

[0026] Preferably, in step S5, the molar ratio of disodium hydrogen phosphate to citric acid in the buffer solution is 3.2:1 to 3.5:1.

[0027] Preferably, in step S4, when adding the composite antibacterial microcapsule powder, first disperse 1 / 2 of the total amount of the composite antibacterial microcapsules at a mass fraction of 5-10% in the W / O type composite emulsion, stir evenly, and then add the remaining composite antibacterial microcapsules to the W / O type composite emulsion.

[0028] Preferably, the oral care composition is in the form of a shear-thinning gel, and has a viscosity of 5000-10000 cP at a shear rate of 10 s-1.

[0029] On the other hand, the present invention also provides an oral care composition obtained according to the above preparation method, comprising the following raw materials in parts by weight:

[0030] Green tea polyphenols 0.5-1.5 parts, lactoferrin 0.5-1.5 parts, grapefruit seed extract 0.5-1.5 parts, beta-cyclodextrin 2-5 parts, chitosan 1-3 parts, nano-hydroxyapatite 0.5-2 parts, sodium fluoride 0.1-0.5 parts, calcium lactate 0.2-0.8 parts, eucalyptol 3-7 parts, spearmint oil 2-6 parts, alpha-tocopherol 0.05-0.2 parts, glycerol 15-25 parts, Tween 80 0.5-2 parts, triethanolamine 0.2-0.6 parts, carbomer 0.3-1 parts, disodium hydrogen phosphate 0.5-2 parts and citric acid 0.1-0.6 parts.

[0031] In another aspect, the present invention also protects the application of the preparation method of the above-mentioned oral care combination in the field of oral care combinations.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] First, in terms of the design of antibacterial components, green tea polyphenols, lactoferrin and grapefruit seed extract are used to construct a composite active system in equal proportions. The three have antioxidant, iron ion chelation and membrane permeability antibacterial mechanisms, respectively, and play a synergistic antibacterial role on different oral bacterial targets. In order to avoid the rapid release or inactivation of active substances during storage or use, the present invention constructs an amphiphilic wall material system by β-cyclodextrin and chitosan in a 5:2 ratio, and encapsulates the active ingredients in microcapsules by non-covalent inclusion. Among them, β-cyclodextrin provides hydrophobic cage embedding ability, and chitosan has positive charge and oral biofilm surface adhesion properties, which can enhance the retention of microcapsules and the sustained release efficiency of antibacterial substances. The microcapsule is formed by a spray drying process (inlet air temperature 140°C, outlet air temperature 75°C), which can quickly form a dense coating layer and control the microcapsule particle size between 80-120μm, which is conducive to achieving structural release under saliva hydration conditions. The obtained microcapsule system has the characteristic of controlled release of about 80% within 4 hours at pH = 6.8, significantly improving the duration of action and utilization efficiency of the antibacterial ingredients.

[0034] In terms of repair function construction, nano-hydroxyapatite is used as the bionic remineralization factor of enamel, and it is synergistically compounded with sodium fluoride and calcium lactate to form a Ca-rich enamel in a near-neutral environment. 2+ The remineralization microenvironment of PO43- and F- ions. The nanohydroxyapatite particle size is controlled at 30-60nm, which can significantly improve its penetration efficiency and deposition effect in the enamel micropores; the introduction of calcium lactate can release Ca in a weakly acidic environment. 2+ , providing a controllable calcium source for slightly damaged tooth surfaces. Ultrasonic dispersion and filtration to remove agglomerated particles ensure the restoration fluid has good dispersibility and storage stability, and prevents precipitation with other ingredients in the main agent.

[0035] For fragrance regulation and breath freshness, eucalyptol and spearmint oil are combined in a 3:2 volume ratio, and α-tocopherol is introduced to enhance the oxidative stability of this volatile component system. This oil phase system is embedded in a W / O composite emulsion at a ratio of 10-15wt%. During use, it is gradually released by shear disturbance, maintaining a fresh breath while avoiding the rapid evaporation and short-lived effects of traditional flavored oral care products.

[0036] The present invention forms a stable W / O emulsion structure through high shear emulsification in terms of structural design. During this process, the repair liquid and the oil phase are synergistically embedded in the aqueous gel system to form composite emulsion droplets with an average aqueous phase particle size of 0.5-1.5 μm. This structure can achieve shear-responsive release during use, that is, the emulsion is gradually broken and the contents are released under the action of the toothbrush bristles or the activity of the oral muscles, so that the antibacterial, repair and fragrance factors are progressively released at different stages of action, effectively matching the functional requirements of the entire process of oral cleaning-antibacterial-protection. In order to further avoid uneven dispersion due to density differences in the antibacterial microcapsules, in terms of physical and chemical environmental control, a buffer system constructed by disodium hydrogen phosphate and citric acid is introduced to accurately control the final formula pH between 6.8 and 7.2. This range is close to the natural pH value of human saliva, which not only helps to maintain the stability of the oral flora, but also prevents sensitive reactions caused by acid corrosion or alkaline stimulation. The molar ratio of the buffer system is controlled between 3.2:1-3.5:1, which can effectively resist pH fluctuations caused by saliva dilution or bacterial metabolism, thereby ensuring environmental stability during the nursing process. DETAILED DESCRIPTION

[0037] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0038] Example 1

[0039] S1: Preparation of composite antibacterial microcapsules

[0040] Weigh 1.0g of green tea polyphenols, 1.0g of lactoferrin, and 1.0g of grapefruit seed extract and dissolve them in 50mL of deionized water. Adjust the pH to 5.0 to form an active ingredient solution. Separately, mix 5.0g of β-cyclodextrin and 2.0g of chitosan in 100mL of 60°C hot water to form a microcapsule wall material solution. Slowly add the active ingredient solution dropwise to the wall material solution at a rate of 10mL / min and magnetically stir for 40 minutes to form a uniformly encapsulated dispersion. Dry the mixture using a spray dryer with an inlet air temperature of 140°C and an outlet air temperature of 75°C. Collect the resulting microcapsule powder, which has an average particle size of 95μm and an encapsulation efficiency of 88%.

[0041] S2: Preparation of nanohydroxyapatite repair solution

[0042] 1.5 g of nanohydroxyapatite was added to a mixture of glycerol (20 mL) and deionized water (80 mL) in a 1:4 volume ratio and dispersed using ultrasonic treatment (power 100 W, frequency 40 kHz) for 10 minutes. Subsequently, 1 g of sodium fluoride (final concentration 1 wt%) and 0.5 g of calcium lactate (final concentration 0.5 wt%) were added, and the pH was adjusted to 6.8. The mixture was stirred thoroughly and filtered through a 0.45 μm filter to obtain a uniform, transparent repair solution.

[0043] S3: Preparation of plant alcohol fragrance oil phase

[0044] Mix 4.2 g of eucalyptol and 2.8 g of spearmint oil in a volume ratio of 3:2, add 0.15 g of α-tocopherol, and stir evenly to form an oil-phase fragrance liquid.

[0045] S4: Preparation of the main agent of the composition

[0046] Take 60g of deionized water as the base solvent, add 20.0g of glycerol, 0.5g of carbomer, 1.0g of Tween 80, and 0.3g of triethanolamine in sequence, stir evenly and adjust the pH to 6.5 to obtain a basic aqueous phase gel. Mix the S2 repair liquid and the S3 oil phase fragrance liquid in a volume ratio of 4:1 and add them to the base gel. Use a high-speed shear emulsifier to emulsify at 8000rpm for 3min to obtain a stable W / O type composite emulsion. First add half of the microcapsule powder (2.0g) to the emulsion, disperse it at a target concentration of 7% of the total mass of the composition, stir evenly, then add the remaining part, and slowly stir to form a functional main agent system.

[0047] S5: pH buffer adjustment

[0048] Weigh 1.5g of disodium hydrogen phosphate and 0.4g of citric acid, dissolve in 10mL of deionized water, and prepare a buffer solution with a molar ratio of about 3.3:1. Add it to the above-mentioned main agent and mix thoroughly. The pH of the final composition is adjusted to 6.9 to prepare a shear-thinning oral care gel product. The finished product is heated at a shear rate of 10s -1 The viscosity was measured to be 8500 cP, and there was no phase separation after storage at room temperature for 30 days.

[0049] Comparative Example 1

[0050] This comparative example is basically the same as the embodiment, except that: in step S1, β-cyclodextrin and chitosan are not compounded to construct the microcapsule wall material, but gelatin is directly used as the embedding material, and other operations remain unchanged.

[0051] Comparative Example 2

[0052] This comparative example is basically the same as the embodiment, except that: in step S2, no calcium lactate is added to cooperate with the calcium source, and only nano-hydroxyapatite and sodium fluoride are used to form the repair solution.

[0053] Comparative Example 3

[0054] This comparative example is basically the same as the embodiment, except that: in step S4, no W / O type composite emulsion structure is used, but the repair liquid, fragrance oil phase and base gel are directly mixed and stirred to form a single-phase system.

[0055] Comparative Example 4

[0056] This comparative example is basically the same as the embodiment, except that: in step S5, no sodium hydrogen phosphate / citric acid buffer adjustment is provided, but pure water is directly used to adjust the pH to 7.0.

[0057] Experimental steps:

[0058] Antibacterial persistence testing method: Agar diffusion method combined with a dynamic antibacterial release assay. Bacterial strain selection: Using the common oral pathogen Streptococcus mutans as a model; samples from Example 1 and Comparative Example 1 were spread onto sterile filter paper discs, placed in the center of a plate inoculated with the bacterial solution, and incubated at constant temperature for 24, 48, and 72 hours before measuring the diameter of the inhibition zone.

[0059] Sustained release experiment: The gel samples were immersed in PBS buffer (pH 6.8) and shaken at 37°C;

[0060] The liquid was collected every 12 hours to measure the antibacterial activity (OD600 method or colony counting method), and new liquid was replaced. The samples were continuously collected for 72 hours to evaluate the persistence of the antibacterial effect.

[0061] Stability and pH buffering capacity test methods:

[0062] Place the preparation in a 40°C accelerated aging environment and observe for stratification, sedimentation, and phase separation within 30 days; record the "emulsion phase separation ratio" = stratification height / total height;

[0063] pH drift test: Store the sample at 25°C for 0, 7, 14, and 30 days before measuring pH. Add trace amounts of HCl or NaOH to perturb the pH and observe whether the pH stabilizes to 6.8-7.2.

[0064] Buffering capacity evaluation: Calculate the buffering capacity β based on the pH change ΔpH before and after adding alkali / acid:

[0065] β=Δ number of moles of added protons or OH- / Δ pH.

[0066] The test results are shown in Table 1.

[0067] Table 1

[0068]

[0069]

[0070] As can be seen from the table, first of all, in terms of antibacterial performance, the embodiment shows a larger inhibition area in the inhibition ring diameter test, and the 24-hour inhibition ring diameter reaches 18.5 mm, which is much higher than the 13.2 mm of Comparative Example 1. This shows that the composite antibacterial microcapsule system constructed by the present invention can effectively release active ingredients during the actual action process, and the release form is more uniform and lasting. Its core mechanism is that the microcapsules are synergistically encapsulated with β-cyclodextrin and chitosan to form a dual-functional wall material structure with both hydrophobic adsorption capacity and biofilm affinity. Among them, the cationic nature of chitosan helps it to stay on the surface of the bacterial membrane, increase the local concentration of antibacterial components, and thus enhance the initial antibacterial efficacy.

[0071] In terms of antibacterial duration, the effective antibacterial effect of Example 1 lasted for over 60 hours, while that of Comparative Example 1 only lasted for 24 hours, a significant difference. This advantage is attributed to the sustained-release control provided by the microcapsule structure: gradual disintegration in saliva allows for the time-dependent release of green tea polyphenols, lactoferrin, and grapefruit seed extract, effectively covering multiple time periods from post-cleansing to pre-meal, maintaining a relatively stable antibacterial environment. In Comparative Example 1, which did not employ microencapsulation, the active ingredients were directly exposed to the formulation system and the external environment, making them susceptible to rapid early release and inactivation, thereby losing their subsequent protective capabilities.

[0072] In the dynamic release experiment, the total number of colonies in the release solution after 72 hours was only 2.6×

[0073] 10 3 CFU / mL, while the comparative example 1 was as high as 1.2×10 5 CFU / mL, the release efficiency and sustained efficacy are far superior to those of the control example. This further verifies that the embedding structure and emulsion dispersion system adopted by the present invention can effectively prolong the release cycle of the antibacterial component and improve its bioavailability.

[0074] In terms of structural stability, the emulsion phase separation ratio of the embodiment is only 1.8%, while that of Comparative Example 3 is as high as 11.4%, indicating that the W / O emulsion structure constructed by the present invention significantly improves the physical stability of the system. In the embodiment, the particle size of the internal aqueous phase is controlled to 0.5-1.5 μm through high shear emulsification, and the repair liquid and the fragrance oil phase are co-encapsulated in the carbomer gel to form a densely distributed emulsion droplet structure. The emulsion droplets are not easy to coalesce or demulsify during storage, maintaining the uniformity of the system. However, in Comparative Example 3, no emulsification structure is adopted, and the components are directly mixed. The interfacial tension of the emulsion system is unbalanced, resulting in severe stratification, making it difficult to ensure uniformity and functional consistency during use.

[0075] In addition, in terms of pH stability and buffering performance, the pH drift of the embodiment is controlled within the range of ±0.1, which is much better than the ±0.6 of Comparative Example 4, indicating that it has stronger environmental adaptability. The key reason is that the present invention uses a buffer system with a molar ratio of disodium hydrogen phosphate to citric acid of 3.2-3.5. This system can effectively maintain the composition between pH = 6.8-7.2, which is not only close to the natural pH value of saliva, but also helps to reduce mucosal irritation and avoid tooth surface damage under acid etching conditions. At the same time, the buffer system has a certain pH self-repair ability, and can quickly adjust to a stable range when local acidification or alkalization occurs in the oral environment. The buffer capacity test results also confirmed this effect. The buffer capacity β value of the embodiment is 0.019 mol / L·pH, which is much higher than 0.005 of Comparative Example 4, indicating that under disturbed conditions, its pH adjustment ability is stronger and the system is more stable.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for preparing an oral care composition, characterized in that: The following steps are involved: S1: Preparation of composite antibacterial microcapsules, including: Dissolve green tea polyphenols, lactoferrin, and grapefruit seed extract in deionized water at a mass ratio of 1:1:1, and adjust the pH to 5.0 to obtain an active ingredient solution; β-cyclodextrin and chitosan were mixed in a mass ratio of 5:2 and dissolved in 60°C hot water to obtain a microcapsule wall material solution; Add the active ingredient solution dropwise to the microcapsule wall material solution and stir to form an embedding dispersion system; The dispersed system is spray-dried at an air inlet temperature of 140° C. and an air outlet temperature of 75° C. to obtain composite antibacterial microcapsules; S2: preparing nano-hydroxyapatite repair solution, including: Nanohydroxyapatite was ultrasonically dispersed in a mixture of glycerol and deionized water at a volume ratio of 1:4 at a mass concentration of 2 wt%. Adding 1 wt % sodium fluoride solution and 0.5 wt % calcium lactate to the dispersion, adjusting the pH to 6.8, stirring evenly, and filtering through a 0.45 μm filter membrane to obtain a nano-hydroxyapatite repair solution; S3: preparing a plant alcohol fragrance oil phase, comprising: Eucalyptus globulus and spearmint oil were mixed in a volume ratio of 3:2, and 0.1 wt % of α-tocopherol was added and stirred to obtain an oil phase fragrance liquid; S4: preparing a main agent of the composition, including: Deionized water was used as solvent, 0.5 wt% carbomer, 20 wt% glycerol, 1 wt% Tween 80 and 0.3 wt% triethanolamine were added and stirred evenly, and the pH was adjusted to 6.5 to obtain a basic aqueous gel; The repair liquid and the oil phase fragrance liquid were added to the basic aqueous phase gel at a volume ratio of 4:1, and high shear emulsification was performed at 8000 rpm for 3 minutes to form a W / O type composite emulsion; Slowly adding the composite antibacterial microcapsule powder to the W / O type composite emulsion and stirring evenly to form a combined system; S5: Adjust the pH buffer system, including: A buffer solution consisting of disodium hydrogen phosphate and citric acid is added to the combined system to adjust the pH to 6.8-7.2 to obtain the oral care composition.

2. The preparation method according to claim 1, characterized in that The average particle size of the composite antibacterial microcapsules in step S1 is 80-120 μm, and the microcapsule coverage rate is ≥85%.

3. The preparation method according to claim 1, characterized in that The particle size of the nano-hydroxyapatite in step S2 is 30-60 nm, and the ultrasonic treatment power is 100 W, the frequency is 40 kHz, and the time is 10 minutes.

4. The preparation method according to claim 1, characterized in that In step S3, the combined volume fraction of eucalyptol and spearmint oil accounts for 10-15 wt % of the total mass of the composition.

5. The preparation method according to claim 1, characterized in that In step S4, the particle size of the water phase of the W / O type composite emulsion is 0.5-1.5 μm.

6. The preparation method according to claim 1, characterized in that In step S5, the molar ratio of disodium hydrogen phosphate to citric acid in the buffer solution is 3.2:1 to 3.5:

1.

7. The preparation method according to claim 1, characterized in that In step S4, when adding the composite antibacterial microcapsule powder, first disperse 1 / 2 of the total amount of the composite antibacterial microcapsules at a mass fraction of 5-10% in the W / O type composite emulsion, stir evenly, and then add the remaining composite antibacterial microcapsules to the W / O type composite emulsion.

8. The preparation method according to claim 1, characterized in that The oral care composition is in the form of a shear-thinning gel. -1 The lower viscosity is 5000-10000 cP.

9. An oral care composition obtained according to the preparation method according to any one of claims 1 to 8, characterized in that: The composition comprises the following raw materials in parts by weight: Green tea polyphenols 0.5-1.5 parts, lactoferrin 0.5-1.5 parts, grapefruit seed extract 0.5-1.5 parts, beta-cyclodextrin 2-5 parts, chitosan 1-3 parts, nano-hydroxyapatite 0.5-2 parts, sodium fluoride 0.1-0.5 parts, calcium lactate 0.2-0.8 parts, eucalyptol 3-7 parts, spearmint oil 2-6 parts, alpha-tocopherol 0.05-0.2 parts, glycerol 15-25 parts, Tween 80 0.5-2 parts, triethanolamine 0.2-0.6 parts, carbomer 0.3-1 parts, disodium hydrogen phosphate 0.5-2 parts and citric acid 0.1-0.6 parts.

10. Use of the preparation method according to any one of claims 1 to 8 in the field of oral care combinations.

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