Antibacterial whitening shower gel and preparation method thereof

Abstract

The invention relates to antibacterial whitening shower gel and a preparation method thereof in the technical field of personal care products, and solves the technical problems of mutual antagonism of effects and lack of intelligent response capability caused by chemical incompatibility of antibacterial and whitening components in existing products. According to the technical scheme, the shower gel comprises a shower gel substrate and a pH-temperature-sensitive dual-carrier synergistic release system, the system is composed of pH response polymer microcapsules and temperature-sensitive phospholipid lipidosome, the pH response polymer microcapsules entrap antibacterial components, the temperature-sensitive phospholipid lipidosome entraps whitening components, and the carrier concentration ratio is 1.8: 1-2.2: 1. The pH response threshold value of the pH response polymer microcapsule is 5.3 to 5.7, and the phase change temperature of the temperature-sensitive phospholipid liposome is 36.5 to 37.5 DEG C. The preparation method comprises the following steps: preparing a pH response polymer microcapsule by adopting an interfacial polymerization method, preparing a temperature-sensitive phospholipid liposome by adopting a film hydration method, compounding according to a carrier concentration ratio, and mixing with a shower gel matrix. The time-sharing precise delivery that the antibacterial component is preferentially released for 2-3 minutes and the whitening component is delayed to be released for 4-5 minutes is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of personal care products, in particular to an antibacterial and whitening shower gel based on a dual-carrier time-sequential synergistic release system and a preparation method thereof. Background Art

[0002] As consumers' demand for functional personal care products continues to increase, shower gels with dual antibacterial and whitening properties have attracted widespread attention. In the existing technology, researchers have developed a variety of carrier technologies for the encapsulation and release of functional ingredients.

[0003] JP2006519178A discloses a topical medication and cosmetic dispensing system that utilizes a dual-chamber structure to store incompatible active ingredients separately, allowing for manual mixing during use. While this technology physically separates the active ingredients from each other during storage, it suffers from complex structure, high manufacturing costs, and a lack of intelligent response mechanisms. Furthermore, it is unable to automatically adjust the release of active ingredients based on changes in the skin microenvironment.

[0004] CN108478478A describes the use of hydrogel microcapsules in cosmetics, using hydrogel as the capsule wall material to encapsulate active ingredients such as cactus flavonoids and mushroom polysaccharides. This technology protects the active ingredients from the effects of light and heat, but its functionality is relatively limited due to its single carrier system. Furthermore, its passive release mechanism makes it difficult to achieve the coordinated release and precise control of multiple active ingredients.

[0005] CN113520984A discloses a private care antibacterial spray formula containing micromolecule-encapsulated antibacterial active substances. Using micromolecule encapsulation technology to encapsulate plant antibacterial extracts, it can achieve 12 hours of long-lasting antibacterial effects. However, this technology is specifically targeted at the private care field, with a relatively limited scope of application and lacking the synergistic mechanism of multiple functional ingredients.

[0006] After searching and analyzing, the existing technology mainly has the following deficiencies: First, when antibacterial and whitening ingredients are added simultaneously in traditional shower gels, there is chemical incompatibility, which leads to antagonism of their efficacy and reduces the overall effect by 20-30%; Second, the effective ingredients cannot be adjusted and released according to the actual needs of the skin, resulting in resource waste and potential skin irritation; Third, existing carrier technologies are mostly single carriers or simple physical separations, lacking the ability to intelligently respond to changes in the skin microenvironment and unable to achieve precise delivery of active ingredients; Fourth, there is a lack of timed release design based on the physiological needs of the skin, which makes it impossible to implement the scientific care logic of first antibacterial and then whitening. Summary of the Invention

[0007] Technical issues The technical problem to be solved by the present invention is that the effective ingredients in existing antibacterial and whitening shower gels have chemical incompatibility, resulting in mutual antagonism of their effects. They lack the ability to intelligently respond to changes in the skin microenvironment and cannot achieve time-based and precise delivery based on the physiological needs of the skin, thus affecting the overall efficacy and user experience of the product.

[0008] Technical Solution To solve the above technical problems, the present invention provides an antibacterial and whitening shower gel, comprising a shower gel base and effective ingredients, and characterized in that it also comprises a pH-thermosensitive dual-carrier synergistic release system, wherein the pH-thermosensitive dual-carrier synergistic release system comprises pH-responsive polymer microcapsules and thermosensitive phospholipid liposomes; the pH-responsive polymer microcapsules encapsulate antibacterial ingredients, and the thermosensitive phospholipid liposomes encapsulate whitening ingredients; the carrier concentration ratio of the pH-responsive polymer microcapsules to the thermosensitive phospholipid liposomes is 1.8:1 to 2.2:1; the pH response threshold of the pH-responsive polymer microcapsules is 5.3 to 5.7, and the phase transition temperature of the thermosensitive phospholipid liposomes is 36.5 to 37.5°C.

[0009] The timed synergistic release refers to a synergistic control mechanism that realizes the release of antibacterial ingredients and whitening ingredients in a preset time sequence through the time difference between pH response and temperature response, ensuring the scientific care logic of antibacterial first and whitening later. The pH-thermosensitive dual-carrier synergistic release system realizes the time-sharing precise delivery of antibacterial ingredients with priority release for 2-3 minutes and delayed release of whitening ingredients for 4-5 minutes through the swelling deformation of pH-responsive polymers within the normal pH range of 4.5-6.5 on the skin and the phase change process of thermosensitive phospholipids at bathing temperature of 36.5-37.5°C. The response time of the pH priority trigger is 2 to 3 minutes, and the delayed release time of the temperature trigger is 4 to 5 minutes, realizing a time difference control of 1 to 3 minutes.

[0010] The wall material of the pH-responsive polymer microcapsules is polyacrylic acid-methyl methacrylate copolymer, with a molar ratio of acrylic acid to methyl methacrylate of 1:3 to 1:4, and a cross-linking degree of 10 to 13%, as determined by a swelling method. The thermosensitive phospholipid liposomes are composed of dipalmitoylphosphatidylcholine and cholesterol, with a mass ratio of dipalmitoylphosphatidylcholine to cholesterol of 6:3 to 5:2.

[0011] The particle size of the pH-responsive polymer microcapsules and thermosensitive phospholipid liposomes is controlled between 150 and 400 nm, with a polydispersity index (PDI) of ≤0.35, ensuring the uniformity and stability of the carrier. The carrier integrity rate is ≥85%, as determined by microscopic counting.

[0012] The antibacterial component is selected from one or more of benzalkonium chloride, polyhexamethyleneguanidine hydrochloride, and chlorhexidine, and the whitening component is selected from one or more of arbutin, kojic acid, and vitamin C derivatives. The pH-responsive polymer microcapsules have an encapsulation efficiency of 70-75% for the antibacterial component, and the thermosensitive phospholipid liposomes have an encapsulation efficiency of 65-70% for the whitening component.

[0013] The synergistic index CI value of the dual-carrier synergistic release system is 0.75-0.85, and the synergistic index is calculated according to the Chou-Talalay method, and the calculation formula is: ,in and are the dosages of each component in the combination, and The doses required to produce the same effect when each component is used alone.

[0014] The skin irritation index of the antibacterial whitening shower gel is 12 to 18. The skin irritation index is measured using an in vitro reconstructed human skin model and is calculated by measuring cell viability according to the OECD TG 439 standard. The calculation formula is: , An index of <20 indicates mild irritation, 20-50 indicates moderate irritation, and >50 indicates strong irritation. The pH-temperature-sensitive dual-carrier synergistic release system reduces the skin irritation index by more than 40% compared to the traditional direct addition method through carrier protection and time-sharing precise delivery mechanism.

[0015] The present invention also provides a method for preparing the antibacterial whitening shower gel, comprising the following steps: Step 1: pH-responsive polymer microcapsules are prepared by interfacial polymerization, and a polymerization reaction is carried out at the oil-water interface. The reaction temperature is 64-66° C., the reaction time is 3.8-4.2 hours, the monomer concentration is 14-16%, and the initiator concentration is 0.45-0.55%. The interfacial polymerization reaction is protected by nitrogen and the stirring speed is 280-320 rpm. After the reaction is completed, the microcapsules are purified by centrifugation at a centrifugal speed of 8000-10000 rpm and a centrifugal time of 15-20 minutes. Step 2: Prepare thermosensitive phospholipid liposomes by thin film hydration method, with a phospholipid concentration of 19-21 mg / mL, a hydration temperature of 44-46°C, and an ultrasonic dispersion time of 28-32 minutes. After the thin film is hydrated, it is processed by a high-pressure homogenizer with a homogenization pressure of 12-15 MPa and a homogenization number of 2-3 times; Step 3: Compounding the pH-responsive polymer microcapsules and the thermosensitive phospholipid liposomes at a carrier concentration ratio of 1.8:1 to 2.2:1. The compounding process adopts a stepwise addition method, first slowly adding the thermosensitive phospholipid liposome dispersion to the pH-responsive polymer microcapsule dispersion. The addition time is 15 to 20 minutes, the compounding temperature is controlled at 25 to 30° C., the stirring speed is 250 to 350 rpm, and the stirring time is 28 to 32 minutes. Step 4: Mix the compounded dual-carrier dispersion and the shower gel base in a mass ratio of 1:3.8 to 1:4.2, with a homogenization pressure of 14 to 16 MPa and 2 to 3 homogenization times. During the homogenization process, the temperature is controlled at 25 to 35°C.

[0016] During the preparation process, the carrier integrity rate test requirement is ≥85%, which is determined by microscopic counting method, and the number of test samples for each batch is ≥500 carrier particles; the cross-linking degree of the pH-responsive polymer microcapsules is determined by a swelling method, the swelling medium is pH 7.4 phosphate buffer, and the swelling time is 24 hours; the phase transition temperature of the thermosensitive phospholipid liposomes is determined by differential scanning calorimetry.

[0017] The antibacterial whitening shower gel has an inhibition rate of 93±3% against Staphylococcus aureus and an inhibition rate of 88±4% against Escherichia coli; a tyrosinase inhibition rate of 50±3% and a melanin production inhibition rate of 40±3%; the efficacy lasts for 3.5 to 4.5 hours, and the skin irritation index is reduced to 12 to 18; after storage at 25°C for 6 months, the integrity rate of the carrier remains ≥80%, and the efficacy retention rate is ≥85%.

[0018] Beneficial effects The present invention has the following beneficial effects: 1. The pH-temperature-sensitive dual-carrier synergistic release system achieves spatial separation and encapsulation of active ingredients, completely solving the chemical incompatibility problem of antibacterial and whitening ingredients, avoiding the 20-30% efficacy loss in traditional products, and producing a synergistic effect. The synergistic index CI value is 0.75-0.85, which improves the overall efficacy by 20-25%.

[0019] 2. Based on the dual response mechanism of the normal skin pH range of 4.5-6.5 and the bathing temperature of 36.5-37.5℃, when the carrier contacts the skin, the pH-responsive carrier preferentially swells and releases antibacterial ingredients, and the bathing temperature triggers the phase change of the thermosensitive carrier to release whitening ingredients, realizing the time-sharing and precise delivery of antibacterial first and then whitening, which is in line with the scientific logic of skin care.

[0020] 3. The utilization rate of active ingredients is increased from 40-50% of traditional products to 65-75%, the antibacterial effect is improved by 10-15% compared with traditional products, the whitening effect is improved by 25-35%, and the duration of efficacy is extended from 2-3 hours to 3.5-4.5 hours.

[0021] 4. Through carrier protection and time-sharing precise delivery mechanism, the skin irritation index is reduced from 25 of traditional products to 12-18, a reduction of 40%, significantly improving the safety and comfort of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of the pH-temperature sensitive dual carrier synergistic release system of the present invention; Figure 2 It is a process flow chart of the preparation method of the present invention; Figure 3 This is a comparison chart of the effects of the time-sharing precise delivery mechanism of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1 The purpose of this example is to verify the basic technical solution of the pH-temperature sensitive dual-carrier synergistic release system and to demonstrate the encapsulation and time-sharing precise delivery effect of the dual-carrier system on antibacterial and whitening ingredients.

[0025] like Figure 1 As shown, the pH-thermosensitive dual-carrier coordinated release system of this embodiment includes two core components: pH-responsive polymer microcapsules and thermosensitive phospholipid liposomes.

[0026] according to Figure 2 The process flow shown in FIG. 1 , the preparation method of this embodiment includes the following steps: Step 1: Preparation of pH-responsive polymer microcapsules; pH-responsive polymer microcapsules were prepared by interfacial polymerization. Acrylic acid (AA) and methyl methacrylate (MMA) were mixed in a molar ratio of 1:3.5 as monomers, with a total monomer concentration of 15%. Potassium persulfate was used as an initiator at a concentration of 0.5%. Interfacial polymerization was carried out at 65°C for 4 hours under nitrogen protection, with a stirring speed of 300 rpm. After completion of the reaction, the microcapsules were purified by centrifugation at 9000 rpm for 18 minutes to obtain pH-responsive polymer microcapsules.

[0027] The specific method for determining the degree of cross-linking by the swelling method is as follows: the dried microcapsule sample is swollen in a pH 7.4 phosphate buffer for 24 hours to equilibrium, the mass change before and after swelling is measured, and the mass change is calculated according to the formula: , in is the dry weight at swelling equilibrium, The dry weight before swelling was 2.5%. The cross-linking degree was 11.5% and the pH response threshold was 5.5, as determined by the swelling method. Benzalkonium chloride was loaded into the microcapsules as an antibacterial ingredient using the swelling method, achieving an encapsulation efficiency of 72%.

[0028] Step 2: Preparation of thermosensitive phospholipid liposomes; Thermosensitive phospholipid liposomes were prepared using a thin-film hydration method. Dipalmitoylphosphatidylcholine (DPPC) and cholesterol were mixed in a mass ratio of 5.5:2.5, resulting in a total phospholipid concentration of 20 mg / mL. Thin-film hydration was performed at 45°C, followed by ultrasonic dispersion for 30 minutes and homogenization three times using a high-pressure homogenizer at 14 MPa. The phase transition temperature was determined by differential scanning calorimetry to be 37°C. Arbutin, a whitening ingredient, was loaded into the liposomes with an encapsulation efficiency of 67%.

[0029] Step 3: Dual carrier compounding; The prepared pH-responsive polymer microcapsules and thermosensitive phospholipid liposomes were compounded at a carrier concentration ratio of 2:1. The thermosensitive phospholipid liposome dispersion was slowly added to the pH-responsive polymer microcapsule dispersion in a stepwise addition manner for 18 minutes. The mixture was stirred at 300 rpm for 30 minutes. The compounding temperature was controlled at 28°C to obtain a dual-carrier dispersion.

[0030] Step 4: Mix with the matrix; The dual-carrier dispersion and the shower gel base were mixed in a mass ratio of 1:4, homogenized twice under a pressure of 15 MPa, and the temperature was controlled at 30°C during the homogenization process to obtain the final antibacterial and whitening shower gel product.

[0031] Performance testing: The carrier particle size was determined by dynamic light scattering. The average particle size of pH-responsive polymer microcapsules was 280 nm, and the average particle size of thermosensitive phospholipid liposomes was 320 nm. The polydispersity index (PDI) was less than 0.3.

[0032] The specific method of determining the integrity rate of carriers by microscope counting method is as follows: take a sample of carrier dispersion, observe it under an optical microscope, and count the number of intact carrier particles and damaged carrier particles in the field of view. , Each batch of samples tested contained no fewer than 500 vector particles. The vector integrity rate was determined to be 87% using a microscopic counting method, with a sample size of 500 vector particles.

[0033] In vitro release experiments were conducted in a phosphate buffer solution at pH 5.5 at 37°C. The results showed that the pH-responsive polymer microcapsules began to release antibacterial ingredients within 2.5 minutes, and the thermosensitive phospholipid liposomes began to release whitening ingredients after 4.5 minutes, achieving a time difference of 2 minutes. Figure 3 As shown, compared with traditional products, the dual-carrier system of the present invention achieves obvious time-sharing and precise delivery effect. The pH-responsive carrier begins to release antibacterial ingredients within 2.5 minutes, and the temperature-sensitive carrier begins to release whitening ingredients after 4.5 minutes, forming a clear time difference control effect.

[0034] Skin irritation testing: Skin irritation was evaluated using an in vitro reconstructed human skin model according to OECD TG 439. The reconstructed skin model was treated with a diluted shower gel sample (dilution ratio 1:10) for 15 minutes, then rinsed with phosphate buffered saline and incubated for a further 42 hours. Cell viability was determined using the MTT assay, and the skin irritation index was calculated. Results showed that cell viability in the treated group was 85.2%, while that in the control group was 100%. This was calculated using the formula: , It belongs to the non-irritating range (index ≤ 20), indicating that the dual-carrier system of the present invention significantly reduces skin irritation.

[0035] The antibacterial effect was tested using the agar diffusion method, with inhibition rates against Staphylococcus aureus reaching 94% and against Escherichia coli reaching 89%. The whitening effect was tested using spectrophotometry, with inhibition rates of tyrosinase reaching 51% and melanin production reaching 41%.

[0036] The specific formula for calculating the synergy index using the Chou-Talalay method is: , in and are the dosages of each component in the combination, and The doses required to produce the same effect when each component is used alone. Indicates synergy, represents the additive effect, Indicates antagonism. Synergy index was calculated according to the Chou-Talalay method. The value was 0.78, indicating a significant synergistic effect.

[0037] This example verifies that the pH-temperature-sensitive dual-carrier synergistic release system can effectively achieve the separation, encapsulation and time-sharing precise delivery of antibacterial and whitening ingredients, demonstrating the feasibility and effectiveness of the dual-carrier synergistic technology solution.

[0038] Example 2 The purpose of this example is to verify the effect of carrier concentration ratio on the synergistic effect of dual carriers and to demonstrate the effect of optimizing the carrier concentration ratio on improving product performance.

[0039] pH-responsive polymer microcapsules and thermosensitive phospholipid liposomes were prepared according to the method of Example 1, except that the carrier concentration ratio was adjusted to 1.8:1. Other preparation conditions remained unchanged.

[0040] Performance test results: Carrier particle size distribution: The average particle size of the pH-responsive polymer microcapsules was 275 nm, and the average particle size of the thermosensitive phospholipid liposomes was 315 nm. The PDIs were 0.28 and 0.31, respectively. The carrier integrity rate was 85%.

[0041] Time-sharing precise delivery test: pH-responsive polymer microcapsules began to release antibacterial ingredients within 3 minutes, and thermosensitive phospholipid liposomes began to release whitening ingredients after 5 minutes, with the time difference controlled at 2 minutes.

[0042] Efficacy test: The inhibition rate against Staphylococcus aureus was 92%, the inhibition rate against Escherichia coli was 87%, the inhibition rate against tyrosinase was 48%, and the inhibition rate against melanin production was 38%. The synergy index (CI) value was 0.82.

[0043] This example verifies that a good dual-carrier synergistic effect can still be achieved when the carrier concentration ratio is 1.8:1, but the antibacterial and whitening effects are slightly reduced compared to the 2:1 ratio in Example 1, proving that a carrier concentration ratio of 2:1 is a better choice.

[0044] Example 3 The purpose of this example is to verify the technical effect of the upper limit of the carrier concentration ratio of 2.2:1 and to demonstrate the performance of the boundary value of the ratio range.

[0045] A dual-vector system was prepared according to the method of Example 1, except that the vector concentration ratio was adjusted to 2.2:1.

[0046] Performance test results: Carrier particle size distribution: The average particle size of the pH-responsive polymer microcapsules was 285 nm, and the average particle size of the thermosensitive phospholipid liposomes was 325 nm. The PDIs were 0.32 and 0.35, respectively. The carrier integrity rate was 83%.

[0047] Time-sharing precise delivery test: pH-responsive polymer microcapsules began to release antibacterial ingredients within 2 minutes, and thermosensitive phospholipid liposomes began to release whitening ingredients after 5 minutes, with the time difference controlled at 3 minutes.

[0048] Efficacy test: The inhibition rate against Staphylococcus aureus was 96%, the inhibition rate against Escherichia coli was 91%, the inhibition rate against tyrosinase was 49%, and the inhibition rate against melanin production was 39%. The synergy index (CI) value was 0.75.

[0049] This example verifies that the best antibacterial effect can be achieved when the carrier concentration ratio is 2.2:1, but the whitening effect is slightly lower than that of the 2:1 ratio, which proves the rationality of the ratio range of 1.8:1 to 2.2:1.

[0050] Example 4 The purpose of this example is to verify the impact of different pH response thresholds and temperature response thresholds on the accuracy of time-sharing precise delivery and to demonstrate the importance of response parameter optimization.

[0051] The dual-carrier system was prepared according to the method of Example 1, except that the pH response threshold was adjusted to 5.3 and the phase transition temperature of the thermosensitive phospholipid liposome was adjusted to 36.5°C.

[0052] Preparation parameter adjustment: When preparing pH-responsive polymer microcapsules, the cross-linking degree was adjusted to 12% to lower the pH response threshold to 5.3. When preparing thermosensitive phospholipid liposomes, the mass ratio of DPPC to cholesterol was adjusted to 6:3, lowering the phase transition temperature to 36.5°C.

[0053] Performance test results: Time-sharing precise delivery test: Under the conditions of pH 5.3 and 36.5℃, the pH-responsive polymer microcapsules began to release antibacterial ingredients within 2 minutes, and the thermosensitive phospholipid liposomes began to release whitening ingredients after 4 minutes, with the time difference controlled at 2 minutes.

[0054] Efficacy test: The inhibition rate against Staphylococcus aureus was 95%, the inhibition rate against Escherichia coli was 90%, the inhibition rate against tyrosinase was 52%, and the inhibition rate against melanin production was 42%. The synergy index (CI) value was 0.76.

[0055] This example verifies that the accuracy and performance of time-sharing precise delivery can be further optimized by adjusting the response threshold, demonstrating the importance of response parameter design and the adjustability of the technical solution.

[0056] Example 5 The purpose of this example is to verify the technical effect of the upper limit of the response threshold and to demonstrate the performance of a pH response threshold of 5.7 and a phase transition temperature of 37.5°C.

[0057] The dual-carrier system was prepared according to the method of Example 1, except that the pH response threshold was adjusted to 5.7 and the phase transition temperature of the thermosensitive phospholipid liposome was adjusted to 37.5°C.

[0058] Preparation parameter adjustment: When preparing pH-responsive polymer microcapsules, the pH response threshold was increased to 5.7 by adjusting the cross-linking degree to 10%. When preparing thermosensitive phospholipid liposomes, the mass ratio of DPPC to cholesterol was adjusted to 5:2, raising the phase transition temperature to 37.5°C.

[0059] Performance test results: Time-sharing precise delivery test: Under the conditions of pH 5.7 and 37.5°C, the pH-responsive polymer microcapsules began to release antibacterial ingredients within 3 minutes, and the thermosensitive phospholipid liposomes began to release whitening ingredients after 5 minutes, with the time difference controlled at 2 minutes.

[0060] Efficacy test: The inhibition rate against Staphylococcus aureus was 93%, the inhibition rate against Escherichia coli was 88%, the inhibition rate against tyrosinase was 50%, and the inhibition rate against melanin production was 40%. The synergy index (CI) value was 0.80.

[0061] Stability test: After storage at 25°C for 6 months, the integrity of the vector remained at 82% and the efficacy retention rate was 87%.

[0062] This example verifies that the upper limit of the response threshold can still maintain good technical effects, and proves the rationality of the pH response threshold of 5.3 to 5.7 and the phase transition temperature of 36.5 to 37.5°C.

[0063] Comparative Example 1 The purpose of this comparative example is to verify the difference in product performance when the pH-temperature sensitive dual carrier synergistic release system is missing, and to highlight the advantages of the dual carrier synergistic technology of the present invention by comparing it with the traditional direct mixing method.

[0064] A comparative sample was prepared by a conventional method: benzalkonium chloride and arbutin at the same concentration were directly added to the shower gel base without using any carrier system, and the other components remained the same as in Example 1.

[0065] Preparation process: A comparative sample was prepared by directly dissolving 0.2% benzalkonium chloride and 0.3% arbutin in a shower gel base and stirring at room temperature for 2 hours until the mixture was completely dissolved.

[0066] Performance test results: Efficacy test: The inhibition rate against Staphylococcus aureus is 78%, the inhibition rate against Escherichia coli is 72%; the tyrosinase inhibition rate is 32%, and the melanin production inhibition rate is 28%.

[0067] Stability test: After storage at 25°C for 3 months, the antibacterial effect dropped to 65% and the whitening effect dropped to 25%, indicating that the active ingredients were antagonistic and degraded.

[0068] Skin irritation test: Using the same test method, the cell viability of the treated group was 76.2%, and the calculated skin irritation index was 23.8, which is in the mild irritation range (index 20-50), significantly higher than 14.8 in Example 1.

[0069] By comparison, it can be seen that the lack of the pH-temperature-sensitive dual-carrier synergistic release system leads to a 16-17% decrease in antibacterial effect and a 19-23% decrease in whitening effect, and there is an obvious antagonism between the effective ingredients, which proves the necessity and superiority of the dual-carrier synergistic technology of the present invention.

[0070] Comparative Example 2 The purpose of this comparative example is to verify the performance difference between a single carrier system and a pH-temperature sensitive dual carrier synergistic release system, and to demonstrate the technical advantages of the dual carrier synergistic design.

[0071] A single pH-responsive microcapsule was used to simultaneously encapsulate the antibacterial and whitening ingredients. The preparation process was the same as that of the pH-responsive polymer microcapsules in Example 1, but benzalkonium chloride and arbutin were simultaneously encapsulated into the microcapsules.

[0072] Preparation process: During the preparation of pH-responsive polymer microcapsules, benzalkonium chloride and arbutin were added simultaneously and co-encapsulated via a swelling method. The encapsulation efficiency was 65% for benzalkonium chloride and 58% for arbutin.

[0073] Performance test results: Efficacy test: The inhibition rate against Staphylococcus aureus is 83%, the inhibition rate against Escherichia coli is 79%; the tyrosinase inhibition rate is 38%, and the melanin production inhibition rate is 34%.

[0074] Release test: The two active ingredients are released simultaneously, making it impossible to achieve precise delivery at different times.

[0075] Stability test: Since the active ingredients are still in contact with the inside of the carrier, the efficacy decreases by 15-20% after 3 months.

[0076] By comparison, it can be seen that although the single-carrier system is an improvement over direct mixing, it still cannot completely avoid the interaction of active ingredients and cannot achieve precise delivery in a timely manner. The antibacterial and whitening effects are 11-15% and 13-17% lower than those of the dual-carrier system, respectively, proving the technical superiority of the dual-carrier collaborative design.

[0077] Comparative Example 3 The purpose of this comparative example is to verify the effect of different carrier materials on product performance and to demonstrate the advantages of the specific carrier material selection of the present invention by comparison with conventional carrier materials.

[0078] Conventional gelatin microcapsules were used instead of pH-responsive polymer microcapsules, and other conditions were the same as those in Example 1.

[0079] Preparation process: The gelatin microcapsules containing benzalkonium chloride were prepared by complex coacervation, with a gelatin concentration of 3% and an encapsulation efficiency of 60%. The preparation method of thermosensitive phospholipid liposomes was the same as that in Example 1.

[0080] Performance test results: Release test: Gelatin microcapsules have no pH responsiveness and release continuously under various pH conditions, and cannot achieve precise pH-triggered release.

[0081] Efficacy test: Due to the lack of precise release control, the antibacterial effect was 85% and the whitening effect was 43%, both lower than that of Example 1.

[0082] Stability: The gelatin carrier has poor stability in the shower gel environment, and the carrier integrity rate drops to 70% after one month.

[0083] By comparison, it can be seen that conventional carrier materials cannot provide precise environmental response capabilities, resulting in a lack of targeted release of effective ingredients. The overall performance is significantly lower than the specific carrier material combination of the present invention, which proves the scientific nature and advancement of the carrier material selection of the present invention.

[0084] Based on the verification of the above embodiments and comparative examples, the present invention realizes the spatial separation encapsulation and time-sharing precise delivery of the functional ingredients of antibacterial and whitening ingredients through the pH-temperature-sensitive dual-carrier synergistic release system, which solves the technical problem of chemical incompatibility of functional ingredients in traditional products. The dual-carrier synergistic technology not only avoids the mutual antagonism of the functional ingredients, but also produces a synergistic effect, which significantly improves the antibacterial and whitening effects of the product, while reducing skin irritation, and provides a new technical path for the intelligent development of functional personal care products. The pH-responsive polymer microcapsules of the present invention can accurately respond to changes in skin pH, and the thermosensitive phospholipid liposomes can accurately respond to changes in bathing temperature. The two work together to achieve intelligent functional ingredient delivery based on the physiological environment of the skin, reflecting the technological progress of carrier technology from passive release to active response.

Claims

1. An antibacterial whitening shower gel, comprising a shower gel base and functional ingredients, characterized in that: It also includes a pH-temperature-sensitive dual-carrier coordinated release system, which includes pH-responsive polymer microcapsules and thermosensitive phospholipid liposomes; the pH-responsive polymer microcapsules encapsulate antibacterial components, and the thermosensitive phospholipid liposomes encapsulate whitening components; the carrier concentration ratio of the pH-responsive polymer microcapsules to the thermosensitive phospholipid liposomes is 1.8:1 to 2.2:1; the pH response threshold of the pH-responsive polymer microcapsules is 5.3 to 5.7, and the phase transition temperature of the thermosensitive phospholipid liposomes is 36.5 to 37.5°C; the pH-temperature-sensitive dual-carrier coordinated release system realizes the timed coordinated release of pH-prioritized antibacterial component release and temperature-triggered delayed release of whitening component, wherein the response time of pH-prioritized triggering is 2 to 3 minutes, and the delayed release time of temperature-triggered is 4 to 5 minutes, realizing a time difference control of 1 to 3 minutes.

2. The antibacterial whitening shower gel according to claim 1, characterized in that The wall material of the pH-responsive polymer microcapsule is polyacrylic acid-methyl methacrylate copolymer, the molar ratio of acrylic acid to methyl methacrylate is 1:3-1:4, the cross-linking degree is 10-13%, and the cross-linking degree is determined by a swelling method; the thermosensitive phospholipid liposome is composed of dipalmitoylphosphatidylcholine and cholesterol, and the mass ratio of dipalmitoylphosphatidylcholine to cholesterol is 6:3-5:

2.

3. The antibacterial whitening shower gel according to claim 1, characterized in that The particle sizes of the pH-responsive polymer microcapsules and the thermosensitive phospholipid liposomes are both 150-400 nm, and the polydispersity index (PDI) is ≤0.35; the total concentration of the pH-thermosensitive dual-carrier synergistic release system in the shower gel matrix is ​​9-11%; the carrier integrity rate is ≥85%, and the carrier integrity rate is determined by a microscope counting method.

4. The antibacterial whitening shower gel according to claim 1, characterized in that The antibacterial component is selected from one or more of benzalkonium chloride, polyhexamethyleneguanidine hydrochloride, and chlorhexidine, and the encapsulation rate of the pH-responsive polymer microcapsule for the antibacterial component is 70-75%; the whitening component is selected from one or more of arbutin, kojic acid, and vitamin C derivatives, and the encapsulation rate of the thermosensitive phospholipid liposome for the whitening component is 65-70%.

5. The antibacterial whitening shower gel according to claim 1, characterized in that The pH-responsive polymer microcapsules swell and release antibacterial components within the normal pH range of 4.5 to 6.5 on the skin, and the thermosensitive phospholipid liposomes undergo phase change and release whitening components within the bathing temperature range of 36.5 to 37.5°C. The synergistic index CI value of the dual-carrier synergistic release system is 0.75 to 0.85, and the synergistic index is calculated according to the Chou-Talalay method.

6. A method for preparing the antibacterial whitening shower gel according to claim 1, characterized in that: The method comprises the following steps: step 1: preparing pH-responsive polymer microcapsules by adopting an interfacial polymerization method, carrying out a polymerization reaction at an oil-water interface, wherein the reaction temperature is 64-66° C., the reaction time is 3.8-4.2 hours, the monomer concentration is 14-16%, and the initiator concentration is 0.45-0.55%; step 2: preparing thermosensitive phospholipid liposomes by adopting a thin film hydration method, wherein the phospholipid concentration is 19-21 mg / mL, the hydration temperature is 44-46° C., and the ultrasonic dispersion time is 28-32 minutes; step 3: compounding the pH-responsive polymer microcapsules and the thermosensitive phospholipid liposomes at a carrier concentration ratio of 1.8:1-2.2:1, the stirring speed is 250-350 rpm, and the stirring time is 28-32 minutes; and step 4: mixing the compounded dual-carrier dispersion liquid with a shower gel matrix at a mass ratio of 1:3.8-1:4.2, and the homogenization pressure is 14-16 MPa.

7. The preparation method according to claim 6, characterized in that In the step 1, the interfacial polymerization reaction is protected by nitrogen, the stirring speed is 280-320 rpm, and after the reaction is completed, it is purified by centrifugation, the centrifugal speed is 8000-10000 rpm, and the centrifugation time is 15-20 minutes; in the step 2, after the film is hydrated, it is processed by a high-pressure homogenizer, the homogenization pressure is 12-15 MPa, and the number of homogenization times is 2-3 times.

8. The preparation method according to claim 6, characterized in that In the step three, the compounding process adopts a gradual addition method, first slowly adding the thermosensitive phospholipid liposome dispersion into the pH-responsive polymer microcapsule dispersion, the addition time is 15 to 20 minutes, and the compounding temperature is controlled at 25 to 30°C; in the step four, the homogenization pressure is 14 to 16 MPa, the homogenization times are 2 to 3 times, and the temperature is controlled at 25 to 35°C during the homogenization process.

9. The preparation method according to claim 6, characterized in that During the preparation process, the carrier integrity rate test requirement is ≥85%, which is determined by microscopic counting method, and the number of test samples for each batch is ≥500 carrier particles; the cross-linking degree of the pH-responsive polymer microcapsules is determined by a swelling method, the swelling medium is pH 7.4 phosphate buffer, and the swelling time is 24 hours; the phase transition temperature of the thermosensitive phospholipid liposomes is determined by differential scanning calorimetry.

10. Use of the antibacterial whitening shower gel according to claim 1 in preparing functional personal care products, characterized in that: The antibacterial whitening shower gel has an inhibition rate of 93±3% against Staphylococcus aureus and an inhibition rate of 88±4% against Escherichia coli; a tyrosinase inhibition rate of 50±3% and a melanin production inhibition rate of 40±3%; the efficacy lasts for 3.5 to 4.5 hours, and the skin irritation index is reduced to 12 to 18; after storage at 25°C for 6 months, the integrity rate of the carrier remains ≥80%, and the efficacy retention rate is ≥85%.

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