Anti-allergic heavy-metal-free black plaster and preparation method thereof
By using low-temperature frying and colloid milling processes to prepare heavy metal-free black plasters, the problem of heavy metal sensitization in traditional black plasters has been solved, and the safety and stability have been improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUIZHOU MIAOLAOJI PHARMA
- Filing Date
- 2026-03-13
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional black plasters contain heavy metals such as lead, arsenic, and mercury, which can cause contact allergic reactions. Furthermore, the manufacturing process is unstable, affecting the safety and compliance of users.
A low-temperature frying process is used to carbonize the medicinal powder. Combined with colloid milling and natural rubber/resin, a black plaster free of heavy metals is prepared, avoiding high-temperature frying and the use of artificial pigments, thus ensuring process controllability and biocompatibility.
It completely eliminates the risk of heavy metal allergies, reduces allergic reactions, improves the uniformity and efficacy of the plaster, and ensures the stability and safety of the product.
Smart Images
Figure CN122005508A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of drug preparation, and more specifically, it relates to an anti-allergic, heavy metal-free black plaster and its preparation method. Background Technology
[0002] Black plaster, as a traditional Chinese medicine external application dosage form, has the advantages of long-lasting efficacy and convenient use, and is widely used for the treatment of joint pain, musculoskeletal injuries, and other ailments. The traditional preparation process of black plaster generally includes: crushing the medicinal materials and sieving them, frying them in sesame oil at high temperature until they turn golden brown, removing the residue, continuing to heat the medicinal oil until it reaches the state of "dropping water forming beads", removing it from the heat, adding litharge and melanin and stirring to form a paste, cooling it, and then spreading it on the backing material.
[0003] However, traditional processes suffer from the following long-standing drawbacks: First, lead tetroxide (the main component of lead tetroxide) and artificial melanin contain heavy metals such as lead, arsenic, and mercury, which can easily penetrate the skin during application, causing contact allergic reactions such as redness, swelling, itching, and even ulceration at the application site, severely impacting safety and patient compliance. Second, traditional processes rely on high-temperature frying and the experience-based method of "dropping water forming beads," resulting in poor process control and potential damage to active ingredients or unstable plaster quality. Furthermore, to achieve the distinctive appearance of black plasters, pigments must be added, further increasing the risk of sensitization and chemical residues.
[0004] To address the allergy issue, existing technologies have attempted to add antihistamines or use hypoallergenic adhesives to plasters, but these have failed to fundamentally prevent the introduction of heavy metals. Other studies have explored alternative coloring methods, but these often affect the plaster's adhesion or drug release. Therefore, there is an urgent need for a preparation method that retains the appearance and efficacy of traditional black plasters while completely eliminating the risk of heavy metal allergies.
[0005] The present invention aims to overcome the above-mentioned defects of the prior art and provide a method for preparing a black plaster that is free of litharge and artificial pigments, has a controllable process, and possesses anti-allergic properties. Summary of the Invention
[0006] To address the aforementioned issues, this application provides an anti-allergic, heavy metal-free black plaster and its preparation method.
[0007] The technical solution adopted in this application is as follows:
[0008] In a first aspect, this application provides a method for preparing an anti-allergic, heavy metal-free black plaster, comprising:
[0009] The medicinal materials are pulverized and then sieved to obtain medicinal powder;
[0010] The medicinal powder is mixed with vegetable oil and then stir-fried at a low temperature of 150-200℃ until the medicinal powder is carbonized and charred, resulting in a mixture of medicinal oil and charred medicinal powder.
[0011] The mixture was ground and refined using a colloid mill to obtain a uniform and fine slurry;
[0012] After heating the slurry, natural rubber and / or natural resin are added, and the mixture is stirred until a uniform gel-like paste is formed.
[0013] The gel-like ointment is cooled and then coated to form the anti-allergic, heavy metal-free black plaster.
[0014] Furthermore, the mass ratio of the above-mentioned medicinal powder to vegetable oil is 1:2-2.5.
[0015] Furthermore, the aforementioned natural rubber is natural rubber latex or cyclized natural rubber; and / or, the natural resin is selected from at least one of rosin, hydrogenated rosin glycerol ester or dammar resin.
[0016] Furthermore, the amount of natural rubber and / or natural resin added is 5%-30% of the mass of the mixture of the medicinal oil and the medicinal powder charcoal.
[0017] Furthermore, the above-mentioned colloid milling process grinds the mixture until the solid particle size is below 10 micrometers, and the grinding is refined by 2-4 cycles of cyclic grinding.
[0018] Furthermore, the aforementioned vegetable oil is selected from at least one of sesame oil, soybean oil, rapeseed oil, and blended vegetable oils.
[0019] Furthermore, the above-mentioned medicinal powder is obtained by pulverizing the medicinal materials and passing them through a 100-400 mesh sieve.
[0020] Furthermore, the above-mentioned low-temperature stir-frying time is 1.5-2 hours.
[0021] Furthermore, during the aforementioned low-temperature frying process, the endpoint of the carbonization of the medicinal powder is determined by monitoring changes in the viscosity of the medicinal oil or the content of specific components.
[0022] Secondly, this application also provides an anti-allergic, heavy metal-free black plaster prepared by the above-mentioned preparation method, which is free of litharge and artificial synthetic pigments.
[0023] In summary, this application has the following beneficial effects:
[0024] 1. This invention eliminates the introduction of allergenic heavy metals such as lead, arsenic, and mercury at the source by completely discarding the lead oxide (red lead) and artificial pigments required in traditional processes. Simultaneously, by using natural rubber and / or natural resin as the molding matrix, supplemented with pure plant-derived oils, the biocompatibility of all raw materials is ensured, thereby significantly reducing the risk of allergic reactions such as contact dermatitis, redness, and itching in users, providing the market with a truly anti-allergic black plaster product.
[0025] 2. This application employs a low-temperature stir-frying process at 150-200℃ instead of the traditional high-temperature frying, which more gently promotes the slow release of the active ingredients of the medicinal materials into the oil phase, reducing the damage of heat-sensitive active ingredients to high temperatures. More importantly, the "medicinal powder charcoal" formed by the carbonization of the medicinal powder during this process not only gives the ointment a natural black color without the need for external pigments, but its microporous structure may also endow it with adsorption properties similar to activated charcoal, which helps to locally astringe and adsorb metabolites, potentially enhancing the adjuvant therapeutic effect of the ointment.
[0026] 3. This application introduces a colloid mill to finely grind the carbonized mixture, reducing the particle size of solid particles to below 10 micrometers. This results in a paste with a uniform texture, fine consistency, and uniform color, solving the problems of roughness and graininess that may exist in traditional plasters. Furthermore, by clearly defining the raw material ratios, frying temperature, and time range, the reliance on traditional empirical judgments such as "drops forming beads" is reduced, making the entire process more standardized and controllable, laying a technical foundation for large-scale and stable industrial production. Attached Figure Description
[0027] Figure 1 This is a process flow diagram of the anti-allergic, heavy metal-free black plaster provided in Embodiment 1 of this application. Detailed Implementation
[0028] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Specific conditions not specified in the examples shall be carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0029] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.
[0030] Example 1
[0031] This embodiment provides an anti-allergic, heavy metal-free black plaster, the preparation method of which includes:
[0032] (1) Based on the formula of Shenjintong Yaotie, prepare the following medicinal materials and pulverize them through a 100-400 mesh sieve for later use: 4500g of Piper kadsura, 2500g of Zaocys dhumnades, 4500g of Eucommia ulmoides, 1500g of Saposhnikovia divaricata, 1500g of Sargentodoxa cuneata, 1500g of Carthamus tinctorius, 1500g of Ligusticum chuanxiong, 1200g of Sparganium stoloniferum, 1200g of Zingiber officinale, 1000g of Atractylodes lancea, and 200g of Borneol (added later).
[0033] (2) Mix the medicinal powder (excluding borneol) with soybean oil at a mass ratio of 1:2.3, put it into a pot and stir-fry the medicinal powder at a temperature of 180℃ for 1.7h to carbonize the medicinal powder and obtain a mixture of medicinal oil and charred medicinal powder.
[0034] (3) The mixture is ground using a colloid mill process until the particle size of the solid particles is less than 10 micrometers. The mixture is then ground three times to obtain a uniform and fine slurry.
[0035] (4) Place the slurry in an electric heating pot, heat it simultaneously, and add hydrogenated rosin glycerol ester and borneol. The amount of hydrogenated rosin glycerol ester added is 15 wt% of the total mass of the mixture of medicinal oil and medicinal powder charcoal obtained in step (2). Stir until a uniform gel-like paste is formed.
[0036] (5) After cooling the gel-like paste, it is coated and molded to obtain an anti-allergic black plaster free of heavy metals.
[0037] Example 2
[0038] This embodiment provides an anti-allergic, heavy metal-free black plaster, the preparation method of which is the same as that in Example 1, except for the following steps:
[0039] (2) Mix the medicinal powder (excluding borneol) with soybean oil at a mass ratio of 1:2, put it into a pot and stir-fry the medicinal powder at a temperature of 200℃ for 1.5 hours to carbonize the medicinal powder and obtain a mixture of medicinal oil and charred medicinal powder.
[0040] Example 3
[0041] This embodiment provides an anti-allergic, heavy metal-free black plaster, the preparation method of which is the same as that in Example 1, except for the following steps:
[0042] (2) Mix the medicinal powder (excluding borneol) with soybean oil at a mass ratio of 1:2.4, put it into a pot and stir-fry the medicinal powder at a temperature of 150℃ for 1.9h to carbonize the medicinal powder and obtain a mixture of medicinal oil and charred medicinal powder.
[0043] Example 4
[0044] This embodiment provides an anti-allergic, heavy metal-free black plaster, the preparation method of which is the same as that in Example 1, except for the following steps:
[0045] (4) Place the slurry in an electric heating pot and heat it simultaneously. Add natural rubber latex and borneol. The amount of natural rubber latex added is 5 wt% of the total mass of the mixture of medicinal oil and medicinal powder charcoal obtained in step (2). Stir until a uniform gel-like paste is formed.
[0046] Example 5
[0047] This embodiment provides an anti-allergic, heavy metal-free black plaster, the preparation method of which is the same as that in Example 1, except for the following steps:
[0048] (4) Place the slurry in an electric heating pot and heat it simultaneously. Add rosin and borneol. The amount of rosin added is 28 wt% of the total mass of the mixture of medicinal oil and medicinal powder charcoal obtained in step (2). Stir until a uniform gel-like paste is formed.
[0049] Example 6
[0050] This embodiment provides an anti-allergic, heavy metal-free black plaster, the preparation method of which is the same as that in Example 1, except for the following steps:
[0051] (4) Place the slurry in an electric heating pot and heat it simultaneously. Add natural rubber latex, rosin and borneol. The mass ratio of natural rubber latex to rosin is 1:1. The amount of both added is 15wt% of the total mass of the mixture of medicinal oil and medicinal powder charcoal obtained in step (2). Stir until a uniform gel-like paste is formed.
[0052] Comparative Example 1
[0053] This comparative example provides a traditional method for preparing black plaster, also using the Shenjintong Waist Plaster formula as an example, specifically including:
[0054] (1) Prepare the following medicinal materials and pulverize them through a 100-400 mesh sieve for later use: 4500g of Piper kadsura, 2500g of Zaocys dhumnades, 4500g of Eucommia ulmoides, 1500g of Saposhnikovia divaricata, 1500g of Sargentodoxa cuneata, 1500g of Carthamus tinctorius, 1500g of Ligusticum chuanxiong, 1200g of Sparganium stoloniferum, 1200g of Zingiber officinale, 1000g of Atractylodes lancea, and 200g of Borneol (added later).
[0055] (2) Put the medicinal powder (excluding borneol) into boiling soybean oil (the mass ratio of medicinal powder to soybean oil is 1:2.3), fry at high temperature until golden brown, remove the residue and keep the oil, continue to heat the medicinal oil until water droplets in the medicinal oil form beads, and take a small amount of medicinal oil and drop it into water. It is considered to be ready when it does not disperse into beads.
[0056] (3) Stop heating and put litharge, pigment (black pigment) and borneol into the oil pan and stir until a uniform gel-like paste is formed.
[0057] (4) After cooling the gelatinous paste, it is coated and molded to make black plaster.
[0058] Comparative Example 2
[0059] The difference between this comparative example and Example 1 is that the colloid milling process in step (3) is not performed.
[0060] Comparative Example 3
[0061] The difference between this comparative example and Example 1 is that the frying temperature in step (2) is 280°C, and the frying continues until the powder is carbonized and charred.
[0062] Performance testing
[0063] Detection methods / test methods
[0064] Experimental methods
[0065] 1. Detection of heavy metal content and allergens
[0066] Take 10g of each of the black plaster products prepared in Example 1 and Comparative Examples 1-3, and determine the contents of lead (Pb), arsenic (As), and mercury (Hg) in accordance with General Chapter 0821 of the Chinese Pharmacopoeia (Determination of Lead, Cadmium, Arsenic, Mercury and Copper) and the corresponding standards by atomic absorption spectrometry or inductively coupled plasma mass spectrometry (ICP-MS).
[0067] 2. Allergy test
[0068] A guinea pig allergy test model was used. The ointment samples from Example 1 and Comparative Examples 1-3 were applied to shaved skin on the animals. After two weeks of continuous administration, skin reactions such as erythema, edema, and itching at the application site were observed, scored, and recorded. A scoring system was used, with a total score of 4 points; higher scores indicated stronger irritation.
[0069] 3. Evaluation of paste uniformity
[0070] Small amounts of the pastes from Examples 1 and Comparative Examples 1-3 were dispersed in a medium, and the particle size distribution and agglomeration of the solid particles were observed under an optical microscope.
[0071] Experimental Results
[0072] As shown in Table 1.
[0073] Table 1.
[0074]
[0075] As can be seen from Table 1:
[0076] Example 1 of this application, by completely eliminating lead oxide and pigments, showed no detectable heavy metals and had the lowest skin irritation score, thus achieving the core objective of "anti-allergy." Comparative Example 1, containing lead oxide and pigments, had severely excessive heavy metals, leading to strong skin irritation. Comparative Example 2, although free of heavy metals, caused physical irritation due to its rough texture; Comparative Example 3, with its high temperature causing oil oxidation and pyrolysis products, increased chemical irritation.
[0077] Regarding product uniformity and stability, Example 1 achieved a fine, homogeneous, and stable paste through a colloid milling process. Comparative Example 2 lacked this step, resulting in coarse particles and poor uniformity. The traditional stirring method in Comparative Example 1 also led to uneven particle distribution. In Comparative Example 3, high temperature degraded the system's stability, causing it to easily separate into layers.
[0078] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A method for preparing an anti-allergic, heavy metal-free black plaster, characterized in that, It includes: The medicinal materials are pulverized and then sieved to obtain medicinal powder; The medicinal powder is mixed with vegetable oil and then stir-fried at a low temperature of 150-200℃ until the medicinal powder is carbonized and charred, resulting in a mixture of medicinal oil and charred medicinal powder. The mixture was ground and refined using a colloid mill to obtain a uniform and fine slurry; After heating the slurry, natural rubber and / or natural resin are added, and the mixture is stirred until a uniform gel-like paste is formed. The gel-like ointment is cooled and then coated to form the anti-allergic, heavy metal-free black plaster.
2. The method for preparing the anti-allergic, heavy metal-free black plaster according to claim 1, characterized in that, The mass ratio of the medicinal powder to the vegetable oil is 1:2-2.
5.
3. The method for preparing the anti-allergic, heavy metal-free black plaster according to claim 1, characterized in that, The natural rubber is natural rubber latex or cyclized natural rubber; and / or, the natural resin is selected from at least one of rosin, hydrogenated rosin glycerol ester or dammar resin.
4. The method for preparing the anti-allergic, heavy metal-free black plaster according to claim 3, characterized in that, The amount of natural rubber and / or natural resin added is 5%-30% of the mass of the mixture of medicinal oil and medicinal charcoal powder.
5. The method for preparing the anti-allergic, heavy metal-free black plaster according to claim 1, characterized in that, The colloid milling process grinds the mixture until the solid particles have a diameter of less than 10 micrometers, and the grinding is refined by 2-4 cycles of cyclic grinding.
6. The method for preparing the anti-allergic, heavy metal-free black plaster according to claim 1, characterized in that, The vegetable oil is selected from at least one of sesame oil, soybean oil, rapeseed oil, and blended vegetable oil.
7. The method for preparing the anti-allergic, heavy metal-free black plaster according to claim 1, characterized in that, The medicinal powder is obtained by pulverizing the medicinal materials and passing them through a 100-400 mesh sieve.
8. The method for preparing the anti-allergic, heavy metal-free black plaster according to claim 1, characterized in that, The low-temperature stir-frying time is 1.5-2 hours.
9. The method for preparing the anti-allergic, heavy metal-free black plaster according to claim 1, characterized in that, During the low-temperature frying process, the endpoint of the carbonization of the medicinal powder is determined by monitoring changes in the viscosity of the medicinal oil or the content of specific components.
10. A black plaster, free of heavy metals and with anti-allergic properties, prepared by the method according to any one of claims 1-9, characterized in that, The black plaster does not contain litharge or artificial colorings.