An aqueous personal lubricant and its preparation method

Abstract

The present invention belongs to the technical field of chemical products, and particularly relates to an aqueous personal lubricant and a preparation method thereof. The aqueous personal lubricant of the present invention comprises natural ingredients, auxiliary materials and pure water; the natural ingredients include TEMPO-oxidized nanocellulose, hyaluronic acid, squalane, lecithin, and the auxiliary materials include emulsifiers, antioxidants, bactericides, preservatives, etc. This personal lubricant has a continuous and stable lubricating effect and moisturizing ability, adapts to the environmental characteristics such as the PH and osmotic pressure of the human body cavity, and can be used as a lubricant for passive medical devices to enter the human body cavity, especially as a lubricant for condoms.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical products, and particularly relates to an aqueous lubricant and a preparation method thereof. Background Art

[0002] During the process of medical devices such as endoscopes, colposcopes, uterine forceps, and medical catheters entering the human body cavity, it is usually necessary to apply an appropriate amount of lubricant on the surface of the device to reduce the damage of the device to human tissues. Currently, the widely used human lubricants are generally divided into two categories: oil-based matrix and water-based matrix. The oil-based matrix lubricant has a better lubrication effect, but it is completely immiscible with the normal secretions of the human body cavity and has a strong greasy feeling and is not easy to clean. The water-based matrix lubricant has insufficient lubrication efficiency, but has a certain water replenishing and moisturizing function, is extremely easy to clean, and has a high affinity with the skin and vaginal endometrium, and has gradually become the mainstream of the market.

[0003] In addition to achieving the expected uses such as lubrication and water replenishing and moisturizing, the water-based human lubricant should not have a negative impact on the health of the human body cavity. The main factors such as glycerol, propylene glycol, and ethylene glycol contained in the water-based lubricant that determine the osmotic pressure of the lubricant will cause a hypertonic state to the mucosa, thus interfering with the ecosystem of the human body cavity (such as the female vagina), and may even cause symptoms such as burning and itching in the human body cavity. In vitro studies have shown that the osmotic pressure of the water-based lubricant will also have a negative impact on sperm motility (Agarwal A, Fertil Steril, 2008, 89: 375-379). Therefore, the water-based human lubricant should maintain a normal and consistent range with the osmotic pressure of female secretions (260-290 mOsm / kg) and the osmotic pressure of human semen (250-380 mOsm / kg), that is, create an "isotonic" vaginal environment.

[0004] Natural latex condoms generally need to add lubricants to prevent the discomfort and epidermal cell damage caused by the friction between the condom and the vagina. During the use of the condom, according to the state and properties of the lubricating film layer formed by the lubricant between the friction pairs, lubrication can be divided into fluid lubrication and boundary lubrication. In fluid lubrication, the two friction surfaces are separated by a flowable lubricating layer, and the friction coefficient is extremely small, which is an ideal lubrication state. During continuous use, when the lubricant is not sufficient to form a lubricating layer with sufficient thickness or continuity, the lubrication between the two friction surfaces mainly depends on an extremely thin, non-flowing adsorption lubricating film, and at this time, it is in the boundary lubrication state, and the physical and chemical interaction between the lubricant and the friction surface becomes the main factor affecting the lubrication effect. The water-based lubricant has a good affinity with the skin and the mucosal membrane of the cavity and can form a better flowable lubricating layer, but has poor compatibility with the latex surface, and the binding force between the adsorption lubricating film and the latex surface is weak, which results in a generally low lubrication time of the water-based lubricant.

[0005] In summary, an ideal water-based personal lubricant, especially for medical devices such as medical gloves and condoms, should possess the following three characteristics: first, it should have good biocompatibility to create a human body cavity environment with equal pH and equal osmotic pressure; second, it should have excellent lubricating and moisturizing properties to moisten and hydrate the mucous membranes of the human body cavity; third, it should improve the affinity between medical devices and the human body cavity to avoid frictional damage. Summary of the Invention

[0006] The present invention aims to provide a new water-based personal lubricant with good lubricity, strong moisturizing property and meeting the requirements of the human body cavity environment, as well as a preparation method thereof.

[0007] The water-based personal lubricant provided by the present invention comprises natural ingredients, auxiliary materials and pure water; wherein (by weight):

[0008] The natural ingredients include:

[0009] TEMPO-oxidized nanocellulose: 0.5 - 3 wt.%;

[0010] Hyaluronic acid: 0.05 - 1 wt.%;

[0011] Squalane: 0.05 - 0.5 wt.%;

[0012] Lecithin: 0.01 - 0.1 wt.%;

[0013] The auxiliary materials include:

[0014] Emulsifier: 0.02 - 0.2 wt.%;

[0015] Antioxidant: 0.01 - 0.05 wt.%;

[0016] Bactericide: 0.01 - 0.05 wt.%;

[0017] Preservative: 0.01 - 0.05 wt.%;

[0018] The rest is pure water; the total amount is 100%.

[0019] Furthermore:

[0020] The TEMPO-oxidized nanocellulose is nanocellulose modified by a TEMPO (tetramethylpiperidine-N-oxide) oxidation system, with a width of 3 - 50 nm, a length of 0.1 - 20 μm, and a surface carboxyl content of 0.5 - 2.5 mmol / g. The TEMPO-oxidized nanocellulose solution endows the lubricant with non-Newtonian fluid characteristics, and can spread rapidly under external pressure to form a flowing lubricating layer with a certain resistance to deformation between the vagina and the condom. Its surface carboxyl and other polar groups can form hydrogen bonds with water to bind a large amount of water, promoting the hydration of the vaginal mucosal tissue.

[0021] The hyaluronic acid includes hyaluronic acid and its derivatives, with a molecular weight of 3,000 to 3 million. This hyaluronic acid is a mucopolysaccharide that can further improve the wetting and lubricating ability of the lubricant. As an intelligent moisturizing factor in the human body, hyaluronic acid has the physiological functions of regulating osmotic pressure and maintaining the extracellular space. At the same time, it contains a large number of carboxyl and hydroxyl groups, which can form a complex super-hydrogen bond three-dimensional network structure with water and TEMPO-oxidized nanofibrillated cellulose through intra- and intermolecular hydrogen bonds. It not only has a strong water-locking and moisturizing function but also can endow the flowing lubricating layer with certain viscoelasticity, improving the lubrication effect.

[0022] The squalane can be vegetable squalane, animal squalane, or synthetic squalane. As a lipid compound closest to human sebum, squalane is moisturizing and non-greasy. It is incompatible with the aqueous phase but has good compatibility with the surface of the condom. It can be adsorbed on the surface of the natural latex condom through intermolecular van der Waals forces to form a natural protective lubricating film, improving the affinity between the condom surface and the human body cavity and the boundary lubrication effect.

[0023] The lecithin mentioned is soy lecithin, also known as phosphatidylcholine. As an amphoteric surfactant, it has a series of interfacial properties and colloidal properties. The hydrophobic fatty acid chain has good physical adsorption with the latex surface, and the hydrophilic groups such as phosphate and choline have good affinity with the mucosal tissue, synergistically enhancing the lubricating film on the condom surface and improving the natural affinity.

[0024] The present invention also provides a preparation method for the aqueous human lubricant, including the following steps:

[0025] Step 1: Prepare a TEMPO-oxidized nanofibrillated cellulose sol with a target concentration that is transparent and homogeneous.

[0026] Step 2: Heat pure water to 25 - 80°C. Under high-speed stirring (800 - 3000 rpm), slowly add hyaluronic acid to the pure water until the sodium hyaluronate is fully dissolved. Then add lecithin, squalane, emulsifier, and other auxiliary materials to make the multiphase system fully mixed and uniform, obtaining a homogeneous and transparent liquid.

[0027] Step 3: Keep the temperature of the above homogeneous and transparent liquid (25 - 80°C) unchanged, reduce the stirring speed to below 800 rpm, and slowly add the TEMPO-oxidized nanofibrillated cellulose sol. After fully and uniformly mixing, naturally cool the resulting colorless viscous liquid to room temperature.

[0028] Step 4: Adjust the pH of the above colorless viscous liquid to 5 - 7 with a pH regulator to obtain the clear and transparent human lubricant of the present invention.

[0029] The personal lubricant of the present invention has a continuous and stable lubricating efficacy and moisturizing ability, adapts to the environmental characteristics such as the pH and osmotic pressure of the human body cavity, and can be used as a lubricant for passive medical devices to enter the human body cavity, especially as a lubricant for condoms. Description of the Drawings

[0030] Figure 1 is the moisturizing rate of each aqueous personal lubricant.

[0031] Figure 2 is the lubricating performance of each aqueous personal lubricant. Detailed Embodiments

[0032] Example 1

[0033] The personal lubricant of the present invention: TEMPO-oxidized nanocellulose 1 wt.%, sodium hyaluronate 0.2 wt.%, squalane 0.05 wt.%, lecithin 0.01 wt.%, sorbitan monooleate 0.05 wt.%, methyl paraben 0.01 wt.%.

[0034] Example 2

[0035] The personal lubricant of the present invention: TEMPO-oxidized nanocellulose 0.5 wt.%, sodium hyaluronate 0.5 wt.%, squalane 0.02 wt.%, lecithin 0.02 wt.%, sorbitan monooleate 0.05 wt.%, methyl paraben 0.01 wt.%.

[0036] Comparative Example 1

[0037] A commercial aqueous personal lubricant, the main components of which are: water, glycerol, hydroxyethyl cellulose, chlorhexidine gluconate, glucono delta-lactone, methyl p-hydroxybenzoate, sodium hydroxide.

[0038] To further illustrate the excellent performance of the personal lubricant of the present invention, the above examples and comparative examples were subjected to the following verification tests.

[0039] (1) Osmotic pressure and pH value

[0040] The osmotic pressure was measured using a membrane osmometer. The lubricant was diluted 100 times with distilled water and compared with a standard glucose solution of known concentration, and the measured osmotic pressure (mm / min) was converted to mOsm / kg. The pH value of the water-soluble personal lubricant was measured using a PHSJ-6L laboratory pH meter of Shanghai Yidian Scientific Instrument Co., Ltd., and a pH value between 5 and 7 was considered qualified.

[0041] As can be seen from the test results of the pH value and osmotic pressure in Table 1, the pH values of Example 1 and Example 2 are weakly acidic, and the osmotic pressures are 295 mOsm / kg and 284 mOsm / kg respectively, which can be regarded as isosmotic with the vaginal environment (260 - 290 mOsm / kg).

[0042] (2) Moisturizing property

[0043] Weigh 5 g of the samples of the above-mentioned examples and comparative examples respectively, place them in weighing bottles, without covering, and place them in a constant temperature and humidity chamber at 40 °C with a relative humidity (RH) of 30% at the same time. Take them out and weigh them at regular intervals. Among them, the water content of the sample before the test is recorded as m1, and the water content of the sample after the test is recorded as m2. Calculate the moisturizing rate, and calculate the moisturizing rate according to the following formula:

[0044]

[0045] As Figure 1 shown, due to the super-hydrogen bond cross-linked structure formed by TEMPO-oxidized nanocellulose, hyaluronic acid and water, the aqueous personal lubricant of the present invention has excellent water-locking and moisturizing functions, and the moisturizing rate can reach more than 80%.

[0046] (3) Bursting performance

[0047] To test whether the water-soluble personal lubricant affects the mechanical properties of the condom after it is used, a condom bursting volume and pressure test is carried out, and a condom without adding any lubricant is used as the control group. Refer to the guidance in GB / T 7544-2019 and the guidelines for analyzing accelerated aging studies to conduct aging test measurements, that is, place 300 samples in the examples and comparative examples in an aging chamber at 70 ± 2 °C for 7 days.

[0048] From Figure 2 the test results of the bursting performance before and after aging, it can be seen that the aqueous personal lubricant in each example does not affect the bursting performance of the condom after it is used.

[0049] (4) The stimulating effect of the personal lubricant

[0050] The slug mucosal irritation test (SMI) is a more sensitive detection test than the rabbit vaginal irritation test (RVI) and can detect mild mucosal irritation efficacy, that is, the clinical manifestations are genital itching and secretions, even if the RVI test result is negative (Dhondt MMM, Eur J Pharm Biopharm, 2005, 60:419–425.). The specific test method is to place the slug in a petri dish containing 100 g of lubricant and keep it in contact for 30 min, and continuously test for 5 days. When in contact with irritating substances, the slug will actively produce mucus, which is a self-protection mechanism. The NanoOrange protein quantification kit is used to measure the total amount of mucus produced by the slug, and the percentage of this value to the slug's body weight characterizes the irritation efficacy of the lubricant. Less than 15% is non-irritating, 15%-20% is mild irritation, 20-25% is moderate irritation, and greater than 25 is severe irritation.

[0051] Table 3 lists the results of the slug mucosal irritation test of each aqueous personal lubricant. The aqueous personal lubricants in Examples 1 and 2 with the same osmotic pressure as the vaginal environment showed no irritation, while the aqueous personal lubricant in Comparative Example 1 with a higher osmotic pressure had mild irritation, indicating that controlling the osmotic pressure of personal lubricants is necessary to avoid adverse reactions such as skin and genital itching.

[0052] (5) Lubricating performance

[0053] According to the method in GB 10006-1988 Determination of Coefficient of Friction of Plastic Films and Sheets, the dynamic friction coefficient μ of the lubricants in each example and comparative example was detected. In addition, a linear wear-resistant testing machine was used, with the surface of the latex condom wetted by the lubricant as the test surface and the friction counter surface as pigskin. Under a certain pressure, the linear repeated friction speed was 60 times per minute, and the dynamic friction coefficient of the friction surface of the condom was measured every minute to evaluate the lubrication aging time of the lubricants in each example and comparative example on the surface of the latex condom.

[0054] From Figure 2 The lubricating performance test results show that the initial dynamic friction coefficient of the aqueous personal lubricants in Examples 1 and 2 is about 0.1, slightly lower than the initial dynamic friction coefficient of 0.137 of the lubricant in Comparative Example 1. During the continuous linear friction process, the lubricating performance of the lubricant is somewhat lost, but during the 2-4 min period, the lubricating efficacy of the personal lubricant in the examples remains good, and its dynamic friction factor does not show a significant increase compared to the personal lubricant in Comparative Example 1 but enters a period of slow growth.

[0055] This is because the personal lubricant of the present invention has the characteristics of non-Newtonian fluid, has a certain ability to resist external forces, and its rich hydrogen bond cross-linked network endows the lubricant with good viscoelasticity. Both characteristics are beneficial to improving the stability of the flowing lubricating layer. As the friction continues, the flowing lubricating layer loses continuity and fluidity due to continuous consumption, and the dynamic friction coefficient increases sharply. The water-based lubricant of the comparative example has extremely poor affinity with the latex surface and pigskin sebum, quickly loses its lubricating effect, and the dynamic friction coefficient is as high as 1.13. In contrast, after the flowing lubricating layer of the water-based lubricant in the example is consumed, squalane and lecithin play a boundary lubrication role in the adsorption lubricating film formed by latex and pigskin sebum. Therefore, the dynamic friction coefficient of the lubricant in the example is always lower than 1 in the second half of the test, which is better than that of the comparative example.

[0056] In summary, the water-based personal lubricant with the same pH and isotonicity as the vaginal environment proposed by the present invention is non-irritating and has continuous and stable lubricating performance and moisturizing ability.

[0057] Table 1 Osmotic pressure and pH value of each water-based personal lubricant

[0058] Category Osmotic pressure (mOsm / kg) pH value Example 1 299 6.32 Example 2 285 6.71 Comparative Example 1 1800 5.85

[0059] Table 2 Blasting performance of condoms treated with water-based personal lubricants

[0060]

[0061] Table 3 Stimulating efficacy of each water-based personal lubricant.

[0062] Personal lubricant Example 1 Example 2 Comparative Example 1 Stimulation efficacy / % 2.4±1.7 1.8±2.9 18.9±2.3

Claims

1. An aqueous personal lubricant, characterized in that, The components include the main components, excipients and pure water; among which: The main components include: TEMPO-oxidized nanocellulose: 0.5-3 wt.%; Hyaluronic acid: 0.05-1 wt.%; Squalane: 0.05-0.5 wt.%; Lecithin: 0.01-0.1 wt.%; The excipients include: Emulsifier: 0.02-0.2 wt.%; Antioxidant: 0.01-0.05 wt.%; Bactericide: 0.01-0.05 wt.%; Preservative: 0.01-0.05 wt.%; The rest is pure water; the total amount is 100%; The TEMPO-oxidized nanocellulose is nanocellulose modified by a TEMPO oxidation system, with a width of 3-50 nm, a length of 0.1-20 μm, and a surface carboxyl content of 0.5-2.5 mmol / g; The hyaluronic acid includes hyaluronic acid and its derivatives, with a molecular weight of 3,000 to 3 million; The squalane is plant squalane, animal squalane, or synthetic squalane; The lecithin is soy lecithin.

2. The preparation method of the aqueous personal lubricant according to claim 1, characterized in that, The specific steps are as follows: Step 1: Prepare a transparent and homogeneous TEMPO-oxidized nanocellulose sol with a target concentration of TEMPO-oxidized nanocellulose; Step 2: Heat the pure water to 25-80°C, and under the condition of high-speed stirring at 800-3000 rpm, slowly add hyaluronic acid to the pure water. After the hyaluronic acid is fully dissolved, add lecithin, squalane and excipients to make the multiphase system fully mixed and uniform, obtaining a homogeneous and transparent liquid; Step 3: Keep the temperature of the above homogeneous and transparent liquid unchanged, reduce the stirring speed to below 800 rpm, and slowly add the TEMPO-oxidized nanocellulose sol. After full and uniform mixing, naturally cool the obtained colorless viscous liquid to room temperature; Step 4: Adjust the pH of the above colorless viscous liquid to 5-7 with a pH regulator to obtain a clear and transparent human lubricant.

Images