Preparation method of rapamycin gel

Abstract

The invention discloses a rapamycin gel preparation method, which comprises: 1) matrix treatment: adding a gel matrix to a solvent, and stirring to obtain a matrix dispersion liquid; 2) raw material treatment: adding a prescription amount of rapamycin into a permeation accelerant, and then stirring to obtain a rapamycin solution; 3) mixing: under the water bath condition of 0-15 DEG C, slowly adding the rapamycin solution prepared in the step 2) into the matrix dispersion liquid obtained in the step 1) by adopting a vacuumizing mode, then adding a prescription amount of a pH value regulator to adjust the pH value to 5.0-7.0, and stirring to obtain rapamycin gel; and 4) filling. The rapamycin gel obtained by the invention has good stability and use feeling.

Description

Technical Field

[0001] The present application belongs to the technical field of pharmaceutical preparations, and in particular relates to a method for preparing rapamycin gel. Background Art

[0002] Rapamycin, also known as sirolimus, is an immunosuppressant drug commonly used to prevent rejection after organ transplantation and to treat certain types of cancer. The chemical name is (1R, 9S, 12S, 15R, 16E, 18R, 19R, 21R, 23S, 24E, 26E, 28E, 30S, 32S, 35R)-1,18-dihydroxy-12-{(1R)-2-[(1S), 3R, 4R)-4-hydroxy-3-methoxycyclohexyl]-1-methylethyl}-19,30-dimethoxy-15,17,21,23,29,35-hexamethyl-11,36-dioxa-4-azatricyclo[30.3.1.04,9]Hexatria Conta-16,24,26,28-tetraene-2,3,10,14,20-pentanone, CAS No.: 53123-88-9, and the chemical structure is as follows:

[0003]

[0004] Sirolimus is widely believed to be an effective suppressor of immune responses by inhibiting the activity of mammalian target of rapamycin (mTOR). Rapamycin is a key regulator of cell division, proliferation and survival. In addition, studies have clearly demonstrated that mTOR is persistently activated in lymphangioleiomyomatosis (LAM). Sirolimus is administered topically to inhibit mTOR, which not only reduces the systemic side effects that may be caused by oral administration, but also provides a new, less invasive treatment approach. In particular, sirolimus can be used to treat skin lesions associated with tuberous sclerosis complex (TSC).

[0005] Sirolimus sugar-coated tablets developed by Nobel Pharmaceuticals Co., Ltd. of Japan were approved for marketing in Japan on July 4, 2004, and Sirolimus gel 0.2% was approved for marketing on March 23, 2018, under the trade name Gel 0.2%. Sirolimus Gel is the world's first topical therapeutic agent that can be used non-invasively to treat skin lesions associated with tuberous sclerosis complex (TSC).

[0006] According to existing literature, sirolimus has poor stability and is sensitive to light and high temperature conditions.

[0007] Patent CN113332228A discloses a sirolimus gel preparation which solves the stability problem of the sirolimus gel preparation by controlling the ethanol solubility and the pH value of the gel.

[0008] CN105663027A discloses a sirolimus external preparation, a preparation method and uses thereof, and is a new generation of solid submicron drug delivery system made by using solid lipids as carriers and encapsulating or embedding drugs in lipid cores, so that the drugs have good stability.

[0009] The above patent aims to solve the problems of stability and medicinal effect of sirolimus topical preparations, but its production process is relatively complicated. Summary of the invention

[0010] In order to solve the problems existing in the prior art, the present invention provides a method for preparing rapamycin gel, comprising the following steps:

[0011] 1) Matrix treatment: adding the gel matrix into the solvent and then stirring to obtain a matrix dispersion;

[0012] 2) Raw material processing: adding the prescribed amount of rapamycin to the permeation enhancer, and then stirring to obtain a rapamycin solution;

[0013] 3) Mixing: slowly adding the rapamycin solution prepared in step 2) to the matrix dispersion obtained in step 1) in a water bath at 0 to 15° C. by vacuuming, then adding a prescribed amount of a pH adjuster to adjust the pH value to a range of 5.0 to 7.0, stirring, and obtaining a rapamycin gel;

[0014] 4) Filling.

[0015] Furthermore, the temperature of the substrate treatment in step 1) is 20-25°C.

[0016] Furthermore, the stirring speed in step 1) is 350-450 rpm.

[0017] Furthermore, the temperature of the raw material treatment in step 2) is 0-15°C.

[0018] Furthermore, the stirring speed in step 2) is 350-450 rpm.

[0019] Furthermore, the vacuum degree of mixing in step 3) is -0.06 to -0.08 MPa.

[0020] Furthermore, the stirring speed in step 3) is 10 to 150 rpm.

[0021] Further, the composition of the rapamycin gel includes: 0.1-0.5% (w / w) rapamycin, 1-3% (w / w) gel matrix, 40-60% (w / w) permeation enhancer, 0.1-1% (w / w) pH adjuster and 40-60% (w / w) solvent;

[0022] Furthermore, the gel matrix is ​​carbomer, the permeation enhancer is ethanol, the pH adjuster is triethanolamine, and the solvent is purified water.

[0023] In another aspect, the present invention provides a rapamycin gel prepared according to the above method.

[0024] Compared with the prior art, the preparation method of rapamycin gel of the present invention has the following advantages:

[0025] (1) The present invention adopts a simple and efficient method, which makes the production process easy to control and also reduces the production cost. The preparation process of the present invention is not only conducive to large-scale production, but also can ensure the consistency and reliability of product quality.

[0026] (2) The rapamycin gel prepared by the preparation method of the present invention can maintain stable efficacy during storage and is not easily affected by external factors such as light and temperature. This stability enables the gel to continue to exert its therapeutic effect during long-term use, providing patients with more reliable treatment effects.

[0027] (3) The rapamycin gel of the present invention has good rheological properties, so that the gel can be easily spread when applied, and is not easy to produce a sticky feeling, so that patients can feel more comfortable during use. In addition, the gel can form a protective film on the skin surface, which helps to slowly release the drug, thereby achieving a sustained treatment effect.

[0028] (4) The rapamycin gel obtained by the present invention exhibits excellent transdermal performance, ensuring that the drug can effectively penetrate the skin and reach the target site, and has excellent stability and reliability. It can continuously and stably release the drug, thereby ensuring that the patient obtains the expected therapeutic effect during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow curve diagram of viscosity and shear stress of commercially available products as a function of shear rate.

[0030] Figure 2 3 is a flow curve diagram of the viscosity and shear stress of Example 1 as a function of shear rate.

[0031] Figure 3 It is the flow curve diagram of viscosity and shear stress of comparative example 1 as a function of shear rate.

[0032] Figure 4 It is the flow curve diagram of viscosity and shear stress of comparative example 2 as a function of shear rate.

[0033] Figure 5It is a flow curve diagram of viscosity and shear stress of comparative example 7 as a function of shear rate.

[0034] Figure 6 It is a graph showing the change in loss modulus and storage modulus of commercially available products relative to shear strain (linear viscoelastic region).

[0035] Figure 7 It is a curve diagram of the change of loss modulus and storage modulus with respect to shear strain of Example 1 (linear viscoelastic region).

[0036] Figure 8 It is a curve diagram of the change of loss modulus and storage modulus relative to shear strain of comparative example 1 (linear viscoelastic region).

[0037] Fig. 9 It is a curve diagram of the change of loss modulus and storage modulus relative to shear strain of Example 2 (linear viscoelastic region).

[0038] Fig.10 It is a curve diagram of the change of loss modulus and storage modulus relative to shear strain of Example 7 (linear viscoelastic region).

[0039] Fig.11 This is a graph showing shear strain versus time for a commercially available product (creep characteristics).

[0040] Fig.12 This is a graph showing shear strain variation over time in Example 1 (creep characteristics).

[0041] Fig.13 This is a graph showing shear strain variation over time for Comparative Example 1 (creep characteristics).

[0042] Fig.14 This is a graph showing shear strain variation over time for Comparative Example 2 (creep characteristics).

[0043] Fig.15 This is a graph showing shear strain variation over time for Comparative Example 7 (creep characteristics). Fig.16 It is the way of placing drugs in in vitro transdermal test, where T is the homemade preparation and R is the reference preparation (commercially available product). DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0045] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0046] After in-depth research by the inventors of the present application, it was found that in the process of preparing rapamycin gel (hereinafter referred to as "sirolimus gel"), the precise control of the order of adding materials and temperature has a crucial influence on the stability, rheological properties and absorption performance of the final product. The whole process includes the following main steps:

[0047] 1) Matrix treatment: adding the gel matrix into the solvent and then stirring to obtain a matrix dispersion;

[0048] In one embodiment of the present invention, the temperature of the substrate treatment is controlled by a water bath, and the water bath temperature is 20-25°C, for example, 20°C, 21°C, 22°C, 23°C, 24°C or 25°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] In one embodiment of the present invention, the gel matrix is ​​added to the solvent and then stirred. The stirring speed is controlled. Preferably, the stirring speed is 350-450 rpm, for example, 350 rpm, 360 rpm, 370 rpm, 380 rpm, 390 rpm, 400 rpm, 410 rpm, 420 rpm, 430 rpm, 440 rpm or 450 rpm, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable. The stirring method can be common methods such as mechanical stirring, magnetic stirring, ultrasonic stirring, and rotary stirring.

[0050] 2) Raw material processing: adding a prescribed amount of sirolimus to a permeation enhancer, and then stirring to obtain a sirolimus solution;

[0051] In one embodiment of the present invention, the temperature of the raw material treatment is controlled by a water bath, and the water bath temperature is 0-15°C, preferably 2-8°C, for example 2°C, 3°C, 4°C, 5°C, 6°C, 7°C or 8°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0052] In one embodiment of the present invention, sirolimus is added to the permeation enhancer, and then stirred. The stirring speed is controlled, and preferably the stirring speed is 350-450 rpm, for example, 350 rpm, 360 rpm, 370 rpm, 380 rpm, 390 rpm, 400 rpm, 410 rpm, 420 rpm, 430 rpm, 440 rpm or 450 rpm, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable. The stirring method can be common methods such as mechanical stirring, magnetic stirring, ultrasonic stirring, and rotary stirring.

[0053] 3) Mixing: slowly adding the sirolimus solution prepared in step 2) to the matrix dispersion obtained in step 1) in a water bath at 0 to 15° C. by vacuuming, then adding a prescribed amount of a pH adjuster to adjust the pH value to a range of 5.0 to 7.0, stirring, and obtaining a sirolimus gel;

[0054] In one embodiment of the present invention, the mixing temperature is controlled by a water bath, and the water bath temperature is 0-15°C, preferably 2-8°C, for example 2°C, 3°C, 4°C, 5°C, 6°C, 7°C or 8°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] In one embodiment of the present invention, the vacuum degree is -0.06 to -0.08 MPa, such as -0.06 MPa, -0.07 MPa or -0.08 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] In one embodiment of the present invention, the stirring speed of the mixing in step 3) is 10 to 150 rpm, for example, 10 rpm, 20 rpm, 30 rpm, 40 rpm, 50 rpm, 60 rpm, 70 rpm, 80 rpm, 90 rpm, 100 rpm, 110 rpm, 120 rpm, 4130 rpm, 140 rpm or 150 rpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable. The stirring method can be common methods such as mechanical stirring, magnetic stirring, ultrasonic stirring, and rotary stirring.

[0057] In one embodiment of the present invention, the pH value adjusted in step 3) is in the range of 5.0 to 7.0, preferably 5.0 to 6.0, such as 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9 or 6.0, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0058] In one embodiment of the present invention, the composition of sirolimus gel includes: 0.1-0.5% (w / w) sirolimus, 1-3% (w / w) gel matrix, 40-60% (w / w) permeation enhancer, 0.1-1% (w / w) pH adjuster and 40-60% (w / w) solvent;

[0059] In one embodiment of the present invention, the gel matrix is ​​carbomer, the permeation enhancer is ethanol, the pH regulator is triethanolamine, and the solvent is purified water. The present invention does not limit the source and type of raw materials and auxiliary materials. Ethanol can be a common concentration, for example, anhydrous ethanol, 20% ethanol aqueous solution, 30% ethanol aqueous solution, 40% ethanol aqueous solution, 50% ethanol aqueous solution, 60% ethanol aqueous solution, 70% ethanol aqueous solution or 95% ethanol aqueous solution. However, it is not limited to the listed concentrations, and other commonly used concentrations are also applicable.

[0060] Sirolimus has poor stability and is prone to degradation in high temperature environments, so strict temperature control during the preparation process is crucial. This can effectively prevent the degradation of the active ingredients of the drug and ensure the stability and efficacy of the drug.

[0061] Through experimental exploration by the inventors of the present application, it is found that temperature control of the whole process is essential in the preparation of sirolimus gel. In particular, the dissolution temperature and the mixing temperature cannot be too low, because too low a temperature may affect the state of the matrix and the stability of the active ingredients; nor can they be too high, otherwise it will affect the content of related substances, flow characteristics and transdermal absorption effect of the gel. Common preparation methods are usually carried out at room temperature, but this is still not enough to completely avoid these problems.

[0062] The preparation of sirolimus gel under generally mild temperature conditions, such as around 10-15°C, can ensure that the content and stability of related substances in sirolimus gel meet the limit requirements. However, even under such conditions, there is still a certain gap between its rheological properties and transdermal absorption and those of commercially available products. Therefore, only by accurately controlling the dissolution temperature and mixing temperature in the preparation of sirolimus gel within a certain appropriate range can the quality of the final product in terms of related substance content, rheological properties and transdermal absorption be effectively improved.

[0063] Although the specific reasons are not completely clear, the inventors found that the order of adding materials has an important impact on the quality of the final sirolimus gel. The inventors compared different addition orders and found that a specific order of adding raw materials and excipients is crucial to forming a gel with excellent physical and chemical properties, such as suitable viscosity and uniform texture. Inappropriate addition order may lead to uneven drug distribution or affect the interaction of excipients, thereby affecting the overall performance of the product. At the same time, the order of adding materials also has an important impact on the stability of the final product. A reasonable order helps to maintain the activity of the drug and the durability of the product.

[0064] The following are specific examples of the present invention and comparative examples, but the present invention is not limited to the following examples.

[0065] Table 1 Instruments used in Examples and Comparative Examples

[0066] name model factory Fluke Mixing Set Reaction Fisco-1S Shanghai Fluke Technology Development Co., Ltd. Mixer D2004W Shanghai Silo Instrument Co., Ltd. pH meter PB-10 Sartorius Scientific Instruments (Beijing) Co., Ltd. Rheometer MCR92 Anton Paar GmbH Rotational Viscometer DVNXRVTJG AMETEKBrookfieldInc

[0067] Example 1

[0068] The prescription composition is as follows:

[0069] Table 2

[0070]

[0071] Preparation process:

[0072] 1) Add the prescribed amount of purified water to the stirring tank at 25°C in a water bath, set the stirring speed to 400 rpm, and slowly add the prescribed amount of carbomer until the mixture is stirred and hydrated to obtain a carbomer dispersion. Cool the carbomer dispersion to 2-8°C in a 5°C water bath for later use.

[0073] 2) Add the prescribed amount of sirolimus to the prescribed amount of ethanol in a water bath at 5° C., set the stirring speed to 400 rpm, until the sirolimus is completely dissolved, to obtain a sirolimus ethanol solution.

[0074] 3) In a water bath at 5°C, slowly add the sirolimus ethanol solution prepared in step 2) to the carbomer dispersion obtained in step 1). Set the stirring speed to 100 rpm and continue stirring for 10 minutes. While stirring, use a reaction jacket mixing device to maintain the vacuum degree at -0.06 to -0.08 MPa. Then, slowly add the prescribed amount of triethanolamine and continue stirring at 100 rpm for 5 minutes to adjust the pH value to between 5.0 and 7.0. Afterwards, reduce the stirring speed to 20 rpm, while maintaining the vacuum degree at -0.06 to -0.08 MPa for 10 minutes to thoroughly remove any bubbles that may be generated and ensure that the final gel is bubble-free.

[0075] 4) Aluminum tube filling.

[0076] Example 2

[0077] The water bath temperature in step 1) was adjusted from 25°C to 20°C, and the water bath temperature in step 2) was adjusted from 5°C to 2°C. The specific operation is as follows:

[0078] 1) In a 20°C water bath, add the prescribed amount of purified water to a stirring tank, set the stirring speed to 400 rpm, and slowly add the prescribed amount of carbomer until the stirring and hydration are complete to obtain a carbomer dispersion. In a 5°C water bath, cool the carbomer dispersion to 2-8°C for standby use.

[0079] 2) In a 2° C. water bath, add the prescribed amount of sirolimus to the prescribed amount of ethanol, set the stirring speed to 400 rpm, until the sirolimus is completely dissolved, to obtain a sirolimus ethanol solution.

[0080] The formulation and other process steps and conditions are the same as those in Example 1.

[0081] Example 3

[0082] Adjust the water bath temperature from 5°C to 8°C in step 2) and perform the following steps:

[0083] 2) In a water bath at 8° C., add the prescribed amount of sirolimus to the prescribed amount of ethanol, set the stirring speed to 400 rpm, until the sirolimus is completely dissolved, to obtain a sirolimus ethanol solution.

[0084] The formulation and other process steps and conditions are the same as those in Example 1.

[0085] Example 4

[0086] Adjust the water bath temperature from 5°C to 2°C in step 3) and perform the following steps:

[0087] 3) In a water bath at 2°C, slowly add the sirolimus ethanol solution prepared in step 2) to the carbomer dispersion obtained in step 1). Set the stirring speed to 100 rpm and continue stirring for 10 minutes. While stirring, use a reaction jacket mixing device to maintain the vacuum degree at -0.06 to -0.08 MPa. Then, slowly add the prescribed amount of triethanolamine and continue stirring at 100 rpm for 5 minutes to adjust the pH value to between 5.0 and 7.0. Afterwards, reduce the stirring speed to 20 rpm, while maintaining the vacuum degree at -0.06 to -0.08 MPa for 10 minutes to thoroughly remove any bubbles that may be generated and ensure that the final gel is bubble-free.

[0088] The formulation and other process steps and conditions are the same as those in Example 1.

[0089] Example 5

[0090] Adjust the water bath temperature from 5°C to 8°C in step 3) and perform the following steps:

[0091] 3) In a water bath at 8°C, slowly add the sirolimus ethanol solution prepared in step 2) to the carbomer dispersion obtained in step 1). Set the stirring speed to 100 rpm and continue stirring for 10 minutes. While stirring, use a reaction jacket mixing device to maintain the vacuum degree at -0.06 to -0.08 MPa. Then, slowly add the prescribed amount of triethanolamine and continue stirring at 100 rpm for 5 minutes to adjust the pH value to between 5.0 and 7.0. Afterwards, reduce the stirring speed to 20 rpm, while maintaining the vacuum degree at -0.06 to -0.08 MPa for 10 minutes to thoroughly remove any bubbles that may be generated and ensure that the final gel is bubble-free.

[0092] The formulation and other process steps and conditions are the same as those in Example 1.

[0093] Comparative Example 1

[0094] The order of adding materials was adjusted to ethanol + API + water + carbomer + triethanolamine. The prescription composition was the same as that in Example 1. The specific operation was as follows:

[0095] 1) In a 5° C. water bath, add the prescribed amount of sirolimus to the prescribed amount of ethanol, set the stirring speed to 400 rpm, until the sirolimus is completely dissolved, to obtain a sirolimus ethanol solution.

[0096] 2) Add the prescribed amount of purified water and the prescribed amount of carbomer to the sirolimus ethanol solution obtained in step 1) under 5° C. water bath conditions, and set the stirring speed to 400 rpm until the stirring and hydration are complete.

[0097] 3) In a water bath at 5°C, using a reaction jacket mixing device, maintaining a vacuum degree of -0.06 to -0.08 MPa, slowly add the prescribed amount of triethanolamine to the reaction system, and continue stirring at 100 rpm for 5 minutes to adjust the pH value to between 5.0 and 7.0. Afterwards, reduce the stirring speed to 20 rpm, while maintaining a vacuum degree of -0.06 to -0.08 MPa for 10 minutes to completely remove any bubbles that may be generated and ensure that the final gel is bubble-free.

[0098] 4) Aluminum tube filling.

[0099] Comparative Example 2

[0100] The order of adding materials is adjusted to water+carbomer+triethanolamine+(ethanol+API), and the prescription composition is the same as that in Example 1. The specific operations are as follows:

[0101] 1) In a 25°C water bath, add the prescribed amount of purified water to a stirring tank, set the stirring speed to 400 rpm, slowly add the prescribed amount of carbomer until the stirring and hydration are complete to obtain a carbomer dispersion, then slowly add the prescribed amount of triethanolamine, and continue stirring at 100 rpm for 5 minutes to adjust the pH value to between 5.0 and 7.0. In a 5°C water bath, cool the carbomer dispersion to 2 to 8°C for standby use.

[0102] 2) Add the prescribed amount of sirolimus to the prescribed amount of ethanol in a water bath at 5° C., set the stirring speed to 400 rpm, until the sirolimus is completely dissolved, to obtain a sirolimus ethanol solution.

[0103] 3) In a water bath at 5°C, slowly add the sirolimus ethanol solution prepared in step 2) to the carbomer dispersion obtained in step 1). Set the stirring speed to 100 rpm and continue stirring for 10 minutes. While stirring, use a reaction jacket mixing device to maintain the vacuum degree at -0.06 to -0.08 MPa. Afterwards, reduce the stirring speed to 20 rpm, while maintaining the vacuum degree at -0.06 to -0.08 MPa for 10 minutes to completely remove any bubbles that may be generated and ensure that the final gel is bubble-free.

[0104] 4) Aluminum tube filling.

[0105] Comparative Example 3

[0106] Adjust the water bath temperature from 5°C to 0°C in step 2) and perform the following steps:

[0107] 2) Under 0° C. water bath conditions, add the prescribed amount of sirolimus to the prescribed amount of ethanol, set the stirring speed to 400 rpm, until the sirolimus is completely dissolved, to obtain a sirolimus ethanol solution.

[0108] The formulation and other process steps and conditions are the same as those in Example 1.

[0109] Comparative Example 4

[0110] Adjust the water bath temperature from 5°C to 15°C in step 2) and perform the following steps:

[0111] 2) Add the prescribed amount of sirolimus to the prescribed amount of ethanol in a water bath at 15° C., set the stirring speed to 400 rpm, until the sirolimus is completely dissolved, to obtain a sirolimus ethanol solution.

[0112] The formulation and other process steps and conditions are the same as those in Example 1.

[0113] Comparative Example 5

[0114] Adjust the water bath temperature from 5°C to 0°C in step 3) and perform the following steps:

[0115] 3) In a water bath at 0°C, slowly add the sirolimus ethanol solution prepared in step 2) to the carbomer dispersion obtained in step 1). Set the stirring speed to 100 rpm and continue stirring for 10 minutes. While stirring, use a reaction jacket mixing device to maintain the vacuum degree at -0.06 to -0.08 MPa. Then, slowly add the prescribed amount of triethanolamine and continue stirring at 100 rpm for 5 minutes to adjust the pH value to between 5.0 and 7.0. Afterwards, reduce the stirring speed to 20 rpm, while maintaining the vacuum degree at -0.06 to -0.08 MPa for 10 minutes to thoroughly remove any bubbles that may be generated and ensure that the final gel is bubble-free.

[0116] The formulation and other process steps and conditions are the same as those in Example 1.

[0117] Comparative Example 6

[0118] Adjust the water bath temperature from 5°C to 15°C in step 3) and perform the following steps:

[0119] 3) In a water bath at 15°C, slowly add the sirolimus ethanol solution prepared in step 2) to the carbomer dispersion obtained in step 1). Set the stirring speed to 100 rpm and continue stirring for 10 minutes. While stirring, use a reaction jacket mixing device to maintain the vacuum degree at -0.06 to -0.08 MPa. Then, slowly add the prescribed amount of triethanolamine and continue stirring at 100 rpm for 5 minutes to adjust the pH value to between 5.0 and 7.0. Afterwards, reduce the stirring speed to 20 rpm, while maintaining the vacuum degree at -0.06 to -0.08 MPa for 10 minutes to thoroughly remove any bubbles that may be generated and ensure that the final gel is bubble-free.

[0120] The formulation and other process steps and conditions are the same as those in Example 1.

[0121] Comparative Example 7

[0122] The water bath temperature in step 2) was adjusted from 5°C to 15°C, and the water bath temperature in step 3) was adjusted from 5°C to 15°C. The specific operation is as follows:

[0123] 2) Add the prescribed amount of sirolimus to the prescribed amount of ethanol in a water bath at 15° C., set the stirring speed to 400 rpm, until the sirolimus is completely dissolved, to obtain a sirolimus ethanol solution.

[0124] 3) In a water bath at 15°C, slowly add the sirolimus ethanol solution prepared in step 2) to the carbomer dispersion obtained in step 1). Set the stirring speed to 100 rpm and continue stirring for 10 minutes. While stirring, use a reaction jacket mixing device to maintain the vacuum degree at -0.06 to -0.08 MPa. Then, slowly add the prescribed amount of triethanolamine and continue stirring at 100 rpm for 5 minutes to adjust the pH value to between 5.0 and 7.0. Afterwards, reduce the stirring speed to 20 rpm, while maintaining the vacuum degree at -0.06 to -0.08 MPa for 10 minutes to thoroughly remove any bubbles that may be generated and ensure that the final gel is bubble-free.

[0125] The formulation and other process steps and conditions are the same as those in Example 1.

[0126] Comparative Example 8

[0127] The whole process is carried out at room temperature (taking 25° C. as an example), and the prescription composition is the same as that in Example 1. The specific operation is as follows:

[0128] 1) Add the prescribed amount of purified water into a stirring tank, set the stirring speed to 400 rpm, and slowly add the prescribed amount of carbomer until stirring and hydration are complete to obtain a carbomer dispersion.

[0129] 2) adding the prescribed amount of sirolimus to the prescribed amount of ethanol, setting the stirring speed to 400 rpm, until the sirolimus is completely dissolved, to obtain a sirolimus ethanol solution.

[0130] 3) Slowly add the sirolimus ethanol solution prepared in step 2) to the carbomer dispersion obtained in step 1). Set the stirring speed to 100 rpm and continue stirring for 10 minutes. While stirring, use a reaction set mixing device to maintain the vacuum degree at -0.06 to -0.08 MPa. Then, slowly add the prescribed amount of triethanolamine and continue stirring at 100 rpm for 5 minutes to adjust the pH value to between 5.0 and 7.0. Afterwards, reduce the stirring speed to 20 rpm, while maintaining the vacuum degree at -0.06 to -0.08 MPa for 10 minutes to thoroughly remove any bubbles that may be generated and ensure that the final gel is bubble-free.

[0131] The stability, rheological properties and in vitro absorption of the sirolimus gel obtained in Examples 1 to 5 and Comparative Examples 1 to 8 and a commercially available sirolimus gel (trade name Rapalimus, manufacturer: Nobel Pharmaceuticals Co., Ltd., batch number: BG01) were determined.

[0132] Related substance determination method :

[0133] The relevant substances were determined according to high performance liquid chromatography (General Rules 0512 of Part IV of the Chinese Pharmacopoeia 2020 Edition).

[0134] Solvent: acetonitrile-water-glacial acetic acid (800﹕200﹕5)

[0135] Test solution: Accurately weigh 2.0 g of the product (equivalent to 4 mg of sirolimus) and place it in a 20 ml volumetric flask. Add an appropriate amount of solvent and sonicate to dissolve the sirolimus. Dilute to the scale with solvent, shake well, centrifuge at 5000 rpm for 10 minutes, and take the supernatant.

[0136] Reference solution: Accurately weigh about 10 mg of sirolimus reference substance, place it in a 50 ml volumetric flask, add solvent to dissolve and dilute to the scale with acidity, shake well, accurately measure 1 ml, place it in a 100 ml volumetric flask, dilute to the scale with solvent, and shake well.

[0137] System suitability solution: Take appropriate amounts of impurity A, impurity B and sirolimus reference substance, weigh accurately, dissolve in solvent and quantitatively dilute to prepare a solution containing approximately 2 μg of impurity A, 2 μg of impurity B and 200 μg of sirolimus per 1 ml.

[0138] Chromatographic conditions: Octadecylsilane bonded silica gel was used as filler (Agilent ZORBAX SB-C18 注 4.6mm×250mm, 5μm or chromatographic column with equivalent performance); 0.6% glacial acetic acid solution (take 6ml of glacial acetic acid, add 1000ml of water to dissolve, and adjust the pH value to 3.6±0.05 with triethylamine)-1,4-dioxane (42:58) as the mobile phase; the flow rate is 1.0ml per minute; the detection wavelength is 277nm; the column temperature is 40℃; the injection volume is 50μl.

[0139] System suitability requirements: In the system suitability solution chromatogram, impurity A, trans-isomer of sirolimus (main peak), cis-isomer of sirolimus and impurity B should appear in sequence, the separation between the peaks of cis-isomer of sirolimus and impurity B should be greater than 1.5, and the theoretical plate number calculated based on the trans-isomer peak of sirolimus should be no less than 2500.

[0140] Determination method: Accurately measure the reference solution and the test solution, inject them into the liquid chromatograph respectively, and record the chromatogram to 2.0 times the retention time of the main component peak.

[0141] If there are impurity peaks in the chromatogram of the limit test solution, calculated by the main component external standard method based on the sum of the peak areas of the trans-isomer of sirolimus and the cis-isomer of sirolimus, impurity A shall not exceed 6.0%, impurity B shall not exceed 1.0%, other individual impurities shall not exceed 0.2%, and the total impurities (excluding impurity A) shall not exceed 2.0%.

[0142] The degradation products of component II were determined by high performance liquid chromatography (General Rules 0512 of Part IV of the Chinese Pharmacopoeia 2020 Edition).

[0143] Test solution: Accurately weigh 5.0 g of the product (equivalent to 10 mg of sirolimus) and place it in a 25 ml volumetric flask. Add an appropriate amount of acetonitrile and sonicate to dissolve the sirolimus. Dilute to the scale with acetonitrile, shake well, centrifuge at 5000 rpm for 10 minutes, and take the supernatant.

[0144] Reference substance solution: Weigh an appropriate amount of sirolimus reference substance, accurately weigh it, dissolve it in acetonitrile and quantitatively dilute it to make a solution containing about 10 μg per 1 ml.

[0145] System suitability solution: Accurately measure appropriate amounts of impurity C and sirolimus reference substance, dissolve in acetonitrile and quantitatively dilute to prepare a solution containing approximately 4 μg of impurity C and 400 μg of sirolimus per 1 ml.

[0146] The chromatographic conditions were as follows: octadecylsilane bonded silica gel as filler (Agilent ZORBAX SB-C18 4.6 mm × 250 mm, 5 μm or a chromatographic column of equivalent performance); 0.01% trifluoroacetic acid solution as mobile phase A, acetonitrile as mobile phase B; flow rate of 1.2 ml per minute; gradient elution according to Table 3; detection wavelength of 240 nm; column temperature of 35°C; injection volume of 50 μl.

[0147] Table 3

[0148]

[0149] System suitability requirements: In the system suitability solution chromatogram, the separation between the impurity C peak and the sirolimus peak should be greater than 1.5, and the retention time of the sirolimus trans isomer peak should be between 22 and 30 minutes; in the reference solution chromatogram, the theoretical plate number calculated based on the sirolimus trans isomer peak should be no less than 8000, and the signal-to-noise ratio of the sirolimus trans isomer peak height should be greater than 50.

[0150] Determination method: Accurately measure the reference solution and the test solution, inject them into the liquid chromatograph respectively, and record the chromatogram.

[0151] If there are impurity peaks in the chromatogram of the limit test solution, the impurity peak with a relative retention time of 0.45 to 0.91 of the trans isomer peak of sirolimus is taken as the degradation product peak of component II. Calculated according to the following formula, impurity C shall not exceed 1.0%, other single maximum degradation products shall not exceed 0.75%, and the total degradation products shall not exceed 5.0%.

[0152]

[0153] Where: A 单个降解: The peak area of ​​the other single largest degradation product between 0.45 and 0.91; A 总降解 : The sum of the peak areas of the total degradation products between 0.45 and 0.91; A 总 : The sum of all peak areas except the solvent peak; 2.16: The relative response factor of impurity C.

[0154] Table 4

[0155]

[0156] The test results of relevant substances are shown in Table 5. :

[0157] Table 5

[0158]

[0159]

[0160]

[0161]

[0162] According to the data in Table 5, when the commercially available sirolimus gel was stored at 25°C for 7 days, the maximum single impurity in its related substances had reached the limit value of 0.2%, and the impurity content continued to increase thereafter. In addition, the initial content of impurity A was as high as 0.11%, and when stored at 25°C for 30 days, its content had risen to 5.79%, which was very close to the limit value of 6.0%. It can be seen that although the content of related substances in the commercially available sirolimus gel is still within the acceptable limit, its overall impurity content is generally high, indicating that its stability is poor when stored at 25°C.

[0163] It can be seen from the relevant material data of Examples 1 to 5 and Comparative Examples 3 to 8 that by accurately controlling the temperature of step 2) and step 3), the impurity content in the produced sirolimus gel can be significantly reduced and ensured to meet the limit requirements.

[0164] During the short-term storage period (7 days, 15 days and 30 days) at 25°C, the sirolimus gel obtained in Examples 1 to 5 had an increase in the content of the largest single impurity, but the contents of the remaining impurities all met the limit requirements; and when stored at 2 to 8°C for 3 months, 7 months and 15 months, the contents of all related substances were able to be maintained within the prescribed limits.

[0165] When the temperature is controlled too low (e.g., 0°C, see Comparative Example 3) in step 2), the maximum single impurity content of the sirolimus gel obtained in Comparative Example 3 is 0.23% on the 15th day when stored at 25°C, exceeding the limit value, and reaches 0.32% on the 30th day, which is significantly higher than that in Example 1. At the same time, the impurity A content on the 0th day is 0.11%, which is relatively high, and reaches 5.14% after being stored at 2-8°C for 15 months, which is very close to the limit value of 6.0%. If the temperature is too high (e.g., 15°C, see Comparative Example 4), not only will the impurity content increase rapidly during storage at 25°C (the maximum single impurity content is 0.20% on the 15th day), but even at 2-8°C, the impurity A will reach 5.4% after being stored for 15 months, which is very close to the limit value of 6.0%. It can be seen that the operating temperature of step 2) has an important influence on the stability of related substances in the final product.

[0166] Similarly, if the temperature is improperly controlled in step 3 (whether it is too low or too high, see Comparative Examples 5 and 6), the impurity content of the final product under different storage conditions will also exceed the specified limit. Comparative Example 5 In step 3), the temperature is too low (0°C). When the sirolimus gel obtained in Comparative Example 5 is stored at 25°C, the content of the largest single impurity on the 15th day has reached the limit value of 0.29%, and on the 30th day it has reached 0.47%. The other largest degradation products have also reached 0.71% on the 30th day, which is very close to the limit value of 0.75%. At the same time, the content of its impurity A on the 0th day is 0.15%, which is relatively high, and after being stored at 2-8°C for 15 months, it reaches 5.31%. The content of total impurities on the 30th day reaches 1.52%, which is very close to the limit value of 2.0%. In Comparative Example 6, the temperature control in step 3) was too high (15° C.). When the sirolimus gel obtained in Comparative Example 6 was stored at 25° C., the maximum single impurity content reached 0.19% on the 7th day, which was very close to the limit value, and then continued to increase rapidly, far exceeding the limit value; and when stored at 2-8° C. for 3-15 months, the maximum single impurity content began to be very close to the limit value from the 3rd month, and exceeded the limit value at the 15th month (0.21%), which shows that its stability is poor.

[0167] The temperature of step 2) and step 3) of comparative example 7 was controlled at 15°C. When the sirolimus gel obtained in comparative example 7 was stored at 25°C, the maximum single impurity content reached 0.19% on the 15th day, which was very close to the limit value, and reached 0.36% on the 30th day, which was far higher than the limit value and Example 1; and when stored at 2-8°C for 3-15 months, the maximum single impurity content began to be very close to the limit value from the 3rd month, and exceeded the limit value at the 15th month (0.24%).

[0168] The preparation of Comparative Example 8 was carried out at room temperature, and the impurity content of the sirolimus gel obtained was generally high. When stored at 25°C, the maximum single impurity content reached 0.21% on the 15th day, exceeding the limit value, and reached 0.45% on the 30th day, which was much higher than other embodiments, and the total impurity content also exceeded the limit value on the 30th day (2.17%). The other maximum degradation products in the degradation products of component II exceeded the limit value after 7 days of storage at 25°C, and also exceeded the limit value when stored at 2-8°C for 7 months (0.97%). It can be seen that the sirolimus gel obtained under room temperature conditions has poor stability in terms of related substances.

[0169] In summary, strict control of temperature conditions during the production process is essential to maintain the quality stability of sirolimus gel and reduce the impurity content.

[0170] Comparative Examples 1 and 2 compare different order of adding materials. From the data of the relevant substances, it can be seen that when other conditions are the same, the sirolimus gel obtained according to the process sequence of Comparative Example 1 is stored at 25°C, and the maximum single impurity content is 0.19% on the 15th day, which is very close to the limit value, and it has reached 0.32% on the 30th day; it is also very close to the limit value when stored at 2-8°C for 15 months (0.18%). The sirolimus gel obtained according to the process sequence of Comparative Example 2 is stored at 25°C, and the maximum single impurity content is 0.2% on the 15th day, reaching the limit value, and it has reached 0.35% on the 30th day; it is also very close to the limit value when stored at 2-8°C for 7 months (0.18%), and it has reached the limit value of 0.20% in 15 months. The overall stability of Comparative Examples 1 and 2 is worse than that of Example 1. It can be seen that the order of adding materials is equally important for maintaining the quality stability of sirolimus gel and reducing the impurity content.

[0171] Table 6 Flow curve determination method :

[0172] parameter Setting conditions Test Mode Rotation mode; Logarithmic scan; Linear coordinates Rotor pp25 / S Temperature(℃) 25 Insulation time (min) 1 Pre-shearing time(s) 60 Shear rate <![CDATA[0.1~100s -1 ]]> Changes in the time point of taking points 10s~1s Sample gap 0.8mm Data processing model Herschel-Bulkley

[0173] Table 7 Linear viscoelastic region determination method:

[0174]

[0175]

[0176] Table 8 Creep determination method:

[0177] parameter Setting conditions Rotor pp25 / S Temperature(℃) 25 Holding time(s) 60 Sample gap 0.8mm Load phase 91 data points; 0.01S-25S; time 300S; shear stress 13Pa Recovery Phase 91 data points; 0.01S-25S; time 600S; shear stress 0Pa

[0178] The rheological properties test results are shown in Table 9 :

[0179] Table 9

[0180]

[0181] Attached Figures 1 to 5 It is the flow curve diagram of the commercially available product, Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 7 measured according to the method in Table 6. The flow characteristics are measured using an Anton Paar rheometer, and the Herschel-Bulkley model is used to reflect it (a mathematical model commonly used to describe the rheological behavior of non-Newtonian fluids). The shear stress of the fluid in the figure is proportional to the shear rate, that is, when the shear rate increases, the shear stress also increases accordingly, and the viscosity of the fluid gradually decreases with the increase of the shear rate (from left to right). The meanings of each parameter are as follows: Consistency index: b is also called the consistency coefficient. The b value is a measure of viscosity, but it is not equal to the viscosity value. The higher the viscosity, the higher the b value;

[0182] Power law index: p is the flow behavior index or non-Newtonian index, which is a temperature-related parameter. The greater the degree of p deviation from 1, the stronger the non-Newtonian property of the material. When p>1, it is a generalized Bingham fluid shear thickening; when p<1, it is a generalized Bingham fluid shear thinning; when p=1, it is an ideal Bingham fluid.

[0183] Yield stress τ0, flow occurs only when the external force exceeds this stress;

[0184] eta represents viscosity, which is the effective viscosity or apparent viscosity of a plastic fluid;

[0185] Attached Figures 6 to 10 It is a linear viscoelastic zone diagram of the commercially available product, Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 7 measured according to the linear viscoelastic zone determination method in Table 7, wherein the material exhibits a range of approximately linear stress-strain response, i.e., the interval in which the storage modulus is much larger than the loss modulus, i.e., the linear viscoelastic zone. In this region, the behavior of the material can be described by a linear elastic model, which means that the material can be completely restored to its original state without permanent deformation. When the shear strain increases, the situation where G′ and G″ intersect may occur, which is called the “yield point”, marking the beginning of the transition from solid to liquid.

[0186] tau is shear stress, which represents the shear force per unit area;

[0187] gamma is the shear strain, which indicates the degree of deformation of the material when subjected to shear stress;

[0188] Attached Figures 11 to 15The creep diagrams of the commercially available product, Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 7 measured according to the creep determination method in Table 8 are also called time-strain curves. The two curves represent the change of shear stress over time in the loading phase and the recovery phase, respectively. Creep is a phenomenon in which a material undergoes plastic deformation over time, especially when subjected to a constant external force. Creep tests are often used to evaluate the ability of a material to resist long-term loads and to predict its long-term performance.

[0189] η0 is the viscosity at zero shear rate, that is, the viscosity of the material when the shear rate is close to zero. The higher the η0, the stronger the material's ability to resist flow when subjected to force. In the creep process, η0 reflects the amount of energy required for the material to resist deformation and directly affects the creep rate.

[0190] Je0 is the creep rate constant, which describes the rate at which the deformation of a material increases over time under constant stress. The larger the Je0, the faster the creep rate of the material, or the more likely the material is to undergo plastic deformation.

[0191] From Table 9 and the attached Figures 1 to 15 It can be seen from the flow curves, linear viscoelastic region and creep data and figures of the embodiments and comparative examples that the sirolimus gel prepared in Example 1 is highly similar to commercially available products in terms of viscosity and flow curves, linear viscoelastic region and creep. This result shows that it has good rheological properties, better mobile phase and spreadability, thereby providing a better user experience. In contrast, since Comparative Examples 1 and 2 use different feeding sequences, the resulting sirolimus gel has significant differences in rheological properties from commercially available products, which affects its user experience and stability to a certain extent. In addition, Comparative Example 7 did not implement temperature control measures during the preparation process, resulting in the rheological properties of its sirolimus gel also being quite different from those of commercially available products, indicating that its fluidity and spreadability are poor, which in turn affects the user experience and the reliability of the absorption effect.

[0192] In vitro transdermal test (IVPT test)

[0193] In order to investigate the skin permeability of the sirolimus gel obtained in Examples 1 to 5 and Comparative Examples 1 to 8, a transdermal test was performed as follows:

[0194] In vitro transdermal method:

[0195] Method: Franze diffusion cell method Instrument: Transdermal diffusion instrument (SYSTEM 9118-12) Skin: Porcine skin Receptor medium: pH 7.4 phosphate buffer (PBS) Temperature: 32℃±1℃ Speed: 600 rpm

[0196] Receiving solution volume: 12 ml Sample volume: 100 mg (equivalent to 0.2 mg of sirolimus)

[0197] Sampling time: 2h, 4h, 6h, 8h, 12h, 18h and 24h Sampling method: full sampling.

[0198] Detection method:

[0199] Detection method: LC-MS

[0200] HPLC chromatographic conditions:

[0201] Chromatographic column: Octadecylsilane bonded silica gel as filler (Welch XB-C18, 150mm×4.6mm, 5μm or equivalent column) Mobile phase: 0.1% phosphoric acid solution-acetonitrile (50:50)

[0202] Detection wavelength: 254nm Flow rate: 1.0ml / min Injection room temperature: 15℃ Column temperature: 30℃ Injection volume: 10μl MS conditions:

[0203] Ion source ESI+, MRM scan, sirolimus m / z 930.2→865.4, internal standard 32-desmethoxysirolimus m / z 900.2→833.9, analysis time 10.0 min

[0204] Specific operations:

[0205] Solvent A: pH 7.4 phosphate buffer (PBS) Solvent B: acetonitrile

[0206] Reference substance solution (high concentration): Accurately weigh an appropriate amount of sirolimus reference substance, dissolve it in solvent B and quantitatively dilute it to make a solution containing about 20 μg per 1 ml. (For the detection of residual test solution on the skin)

[0207] Reference solution (low concentration): Accurately measure 1 ml of reference solution (high concentration), place in a 20 ml volumetric flask, dilute to scale with solvent B, shake well, then accurately measure 1 ml, place in a 100 ml volumetric flask, dilute to scale with solvent A, shake well. 10 ng / ml is obtained. (For in vitro transdermal and intradermal retention test solution detection)

[0208] In vitro transdermal test solution at each time point: Take 12 portions of pig skin respectively, and weigh the homemade preparation and reference preparation alternately (see Fig.16 ), place it on the pigskin with a 0.5mm thick quantitative ring, fill the sample and scrape the quantitative ring (containing about 100mg of this product), fix the whole group (12 parts) of pigskin after drug application on the sample pool of the transdermal diffusion instrument, start the test, and perform fixed-point sampling according to the above-mentioned sampling time.

[0211] Residue on skin: After the test is completed, take out the diffusion cell and gently scrape off the residual drug on the pig skin with a clean scraper. Place the scraper and the quantitative ring in a 50ml centrifuge tube, accurately add 10ml of acetonitrile, cover and seal, ultrasonicate for 20min, filter, and take the filtrate as the test solution for residue on skin.

[0212] Intradermal retention: Cut the cleaned pig skin into pieces, put it into a 50ml centrifuge tube, add 10ml of acetonitrile, cover and seal, ultrasonicate for 20min, filter, and take the filtrate as the test solution for intradermal retention.

[0213] Calculation formula

[0214] (1) The cumulative transdermal amount Q at time t is calculated according to the following formula:

[0215] Q=Cn×V+∑Ci×Vi

[0216] Where Q is the cumulative amount of transdermal permeation per unit area in time t (%); V is the volume of the solution in the receiving pool; Vi is the volume of the sample; Cn is the measured concentration of the nth sample; Ci is the measured concentration of the n-1th sample;

[0217] (2) Absorption rate (J): J = (Q-Q0) / (h-h0)

[0218] (Q is the cumulative permeability per unit area at the sampling time point (μg·cm -2 ), Q0 is the cumulative permeability per unit area at the previous sampling time point (μg·cm -2 ); h is the sampling time point, h0 is the previous sampling time point)

[0219] (3) Intradermal retention: Intradermal retention = detection concentration of drug in skin homogenate × homogenate dilution volume

[0220] (4) Residue on skin: Residue on skin = Detection concentration of drug in residue × pre-treatment dilution volume

[0221] Total amount of material (%) = 24h cumulative transdermal amount (%) + residual amount on the skin (%) + intradermal retention amount (%)

[0222] Accurately measure the above solutions, inject them into LC-MS respectively, and record the chromatogram.

[0223] The results are shown in Tables 10 and 11:

[0224] Table 10

[0225]

[0226]

[0227] Table 11

[0228] sample <![CDATA[Intradermal retention amount (μg / cm 2 )]]> sample <![CDATA[Intradermal retention amount (μg / cm 2 )]]> Commercially available products 4.12 Comparative Example 1 3.24 Example 1 4.23 Comparative Example 2 3.42 Example 2 3.93 Comparative Example 3 3.26 Example 3 4.50 Comparative Example 4 3.12 Example 4 3.88 Comparative Example 5 2.98 Example 5 3.59 Comparative Example 6 3.09 / / Comparative Example 7 4.77 / / Comparative Example 8 3.22

[0229] By comparing the 90% confidence intervals of the maximum absorption rate (Jmax) permeating the skin per unit area per unit time in the embodiment and the comparative example in Table 10, it can be seen that the 90% confidence interval of the embodiment is narrower, which means that the consistency and reliability of its data are higher and closer to the experimental results of commercially available products. This shows that the maximum rate of sirolimus gel permeating the skin obtained in the embodiment has better stability. In addition, from the comparison of the 90% confidence intervals of the total skin permeation (Atotal) of the embodiment and the comparative example in Table 10, the embodiment also shows a narrower confidence interval, which further confirms that it is highly consistent with the experimental results of commercially available products, and the data is more reliable. This shows that the stability of the cumulative amount of sirolimus gel permeating the skin prepared in the embodiment is also better than that of the comparative example.

[0230] Sirolimus gel is mainly used to treat facial angiofibromas in patients with tuberous sclerosis complex (TSC). It is applied topically and acts directly on the skin lesions to reduce the volume and amount of lesion tissue, thereby improving the appearance of the skin. Unlike transdermal preparations that exert systemic effects, drugs used to treat local skin diseases enter the stratum corneum more and are retained there, exerting antifungal effects, and minimize entry into the dermis and systemic blood circulation, thereby reducing the occurrence of systemic adverse reactions.

[0231] Therefore, for topical preparations that act on the superficial layer of the skin, by measuring the drug content in the stratum corneum or dermis, that is, the skin retention, the distribution of the drug in the skin can be studied and its efficacy can be evaluated. According to the data in Table 11, the intradermal retention of the commercially available product is 4.12 μg / cm 2 . The intradermal retention of the sirolimus gel obtained in Examples 1 to 5 is close to that of the commercially available products, showing good consistency. In contrast, the intradermal retention of the sirolimus gel obtained by adjusting the order of addition (such as Comparative Examples 1 and 2) is significantly lower than that of the commercially available products. As for the sirolimus gel obtained by adjusting the temperature conditions (such as Comparative Examples 3 to 8), its intradermal retention is significantly too low or too high compared with the commercially available products.

[0232] A reasonable preparation process is essential to ensure the effective concentration of the drug in the target treatment area and minimize potential side effects. The embodiment can not only maintain a skin retention amount similar to that of commercially available products, but also provide higher data reliability and better stability. This is of great significance for ensuring the efficacy and safety of drug treatment and thus improving the quality of life of patients.

[0233] The sirolimus gel prepared by the process of the invention has lower impurity content, excellent stability, outstanding rheological properties and transdermal absorption effect.

[0234] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A method for preparing rapamycin gel, characterized in that: The steps include: 1) Matrix treatment: adding the gel matrix into the solvent and then stirring to obtain a matrix dispersion; 2) Raw material processing: adding the prescribed amount of rapamycin to the permeation enhancer, and then stirring to obtain a rapamycin solution; 3) Mixing: slowly adding the rapamycin solution prepared in step 2) to the matrix dispersion obtained in step 1) in a water bath at 0 to 15° C. by vacuuming, then adding a prescribed amount of a pH adjuster to adjust the pH value to a range of 5.0 to 7.0, stirring, and obtaining a rapamycin gel; 4) Filling.

2. The method for preparing rapamycin gel according to claim 1, characterized in that: The temperature of the substrate treatment in step 1) is 20-25°C.

3. The method for preparing rapamycin gel according to claim 2, characterized in that: The stirring speed in step 1) is 350-450 rpm.

4. The method for preparing rapamycin gel according to any one of claims 1 to 3, characterized in that: The temperature of the raw material treatment in step 2) is 0-15°C.

5. The method for preparing rapamycin gel according to claim 4, characterized in that: The stirring speed in step 2) is 350-450 rpm.

6. The method for preparing rapamycin gel according to any one of claims 1 to 5, characterized in that: The vacuum degree of mixing in step 3) is -0.06 to -0.08 MPa.

7. The method for preparing rapamycin gel according to claim 6, characterized in that: The stirring speed in step 3) is 10-150 rpm.

8. The method for preparing rapamycin gel according to any one of claims 1 to 7, characterized in that: The rapamycin gel comprises: 0.1-0.5% (w / w) rapamycin, 1-3% (w / w) gel matrix, 40-60% (w / w) permeation enhancer, 0.1-1% (w / w) pH regulator and 40-60% (w / w) solvent.

9. The method for preparing rapamycin gel according to claim 8, characterized in that: The gel matrix is ​​carbomer, the permeation enhancer is ethanol, the pH regulator is triethanolamine, and the solvent is purified water.

10. Rapamycin gel prepared by the method according to any one of claims 1 to 9.

Images