Irradiation sterilization method of alginate dressing

Abstract

The invention discloses an irradiation sterilization method for an alginate dressing, and aims to solve the problems of toxicity residues of existing EO sterilization, breakage of conventional irradiation molecular chains and the like. The method comprises the following steps: balancing the dressing under gradient temperature and humidity for 12-48 hours, pre-irradiating in inert gas, carrying out main irradiation in two stages, standing at the temperature of less than or equal to 25 DEG C, and sealing. The method is characterized in that the proportion of a crystalline region is reduced by 12% through temperature and humidity balance, the molecular weight retention rate reaches 92% or above through double-stage irradiation, the viscosity loss rate is smaller than or equal to 5% through inert gas control, and balance of the sterilization effect and the molecular stability is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of dressing processing, in particular to an irradiation sterilization method for alginate dressing. Background Art

[0002] In the prior art, alginate dressings are mainly sterilized by ethylene oxide (EO) or conventional gamma ray irradiation. Although EO sterilization can achieve a certain sterilization effect, it is toxic and there is a risk of toxic residue. Once the residue exceeds the standard, it will pose a potential threat to human health when used for patient wound care. At the same time, alginate has a porous structure, and EO penetrates it unevenly, making it difficult to ensure the consistency of the overall sterilization effect. Conventional irradiation sterilization has no chemical residues and overcomes the toxicity problem of EO sterilization. However, it uses a single high-dose irradiation (usually ≥25kGy). This irradiation method will cause the alginate molecular chain to break, causing the gel strength to drop by more than 30%, seriously affecting the performance and use effect of the alginate dressing. Although some studies have tried low-temperature irradiation, attempting to reduce the damage to the alginate molecular structure while ensuring the sterilization effect, they have never been able to resolve the contradiction between molecular degradation and sterilization effect, and it is difficult to achieve a balance between the two. Therefore, there is an urgent need for a new irradiation sterilization method for alginate dressings to solve the above-mentioned problems in the prior art. Summary of the Invention

[0003] (1) Technical issues

[0004] The invention provides a method for irradiation sterilization of alginate dressing, which can avoid toxic residues, ensure sterilization uniformity, prevent alginate molecular chain breakage, and balance molecular degradation and sterilization effect.

[0005] (2) Technical content

[0006] To solve the above technical problems, the technical solution of the present invention is: a method for irradiation sterilization of alginate dressing, comprising the following steps:

[0007] S1. Pretreatment equilibration: Place the alginate dressing encapsulated in the breathable primary packaging in a constant temperature and humidity environment, controlling the temperature to 35-45°C and the relative humidity to 40-60% RH for 12-48 hours;

[0008] S2. Pre-irradiation treatment: Transfer the equilibrated dressing to the irradiation chamber and perform pre-irradiation under an inert gas atmosphere with an irradiation dose of 5-7 kGy and a dose rate of ≤2.5 kGy / h;

[0009] S3. Main irradiation sterilization: Maintain an inert gas environment and increase the irradiation dose to 10-15 kGy in stages, including:

[0010] In the first stage, irradiation was performed at a dose rate of 1.0-1.5 kGy / h to a total dose of 8-10 kGy;

[0011] The second stage is irradiated at a dose rate of 0.5-1.0 kGy / h to a total dose of 10-15 kGy;

[0012] S4. Post-processing: After irradiation, place in an environment ≤25℃ for 24-72 hours, and then transfer to sterile secondary packaging and seal.

[0013] Furthermore, in step S1, the constant temperature and humidity environment is adjusted by gradient: first, the temperature is maintained at 40-45° C. and 50-60% RH for 8-12 hours, and then the temperature is reduced to 35-38° C. and 40-45% RH until equilibrium is reached.

[0014] Furthermore, the inert gas is nitrogen or argon, and the oxygen concentration is controlled to be ≤200 ppm.

[0015] Furthermore, the alginate dressing has a molecular weight of 50-150 kDa and a calcium ion content of 5-15 wt%.

[0016] Furthermore, in step S3, a 2-4 hour interval is provided between the two stages of irradiation, during which the inert gas flow is maintained.

[0017] (3) Technical effects

[0018] Compared with the existing technology, the advantages of the present invention are as follows: the present invention adopts a gradient-regulated constant temperature and humidity environment through the pre-treatment balance link, so that the alginate dressing reaches a more stable state before irradiation, providing a good foundation for subsequent irradiation; the pre-irradiation treatment and the staged main irradiation sterilization design avoid the damage to the alginate molecular chain by a single high-dose irradiation, significantly reduce the decline in gel strength, and effectively maintain the performance of the dressing; the control of the inert gas atmosphere reduces the adverse effects of side reactions such as oxidation on the dressing; an interval period is set between the two stages of irradiation and the flow of inert gas is maintained to further ensure the uniformity and stability of the irradiation effect; the specific static and packaging process of the post-treatment link ensures that the dressing can remain sterile after irradiation. Overall, this method solves the problems of toxic residue and uneven penetration of EO sterilization, as well as the molecular chain breakage caused by conventional irradiation sterilization, achieves a good balance between molecular degradation and sterilization effect, and improves the safety and effectiveness of alginate dressing sterilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic flow chart of the irradiation sterilization method of the alginate dressing of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below with reference to the embodiments.

[0021] Example 1

[0022] Reference Attachment Figure 1 The irradiation sterilization method of alginate dressing comprises the following steps:

[0023] S1. Preconditioning: An alginate dressing with a molecular weight of 80 kDa and a calcium ion content of 8 wt% enclosed in a breathable primary packaging was placed in a constant temperature and humidity environment. The temperature was initially maintained at 42°C and a relative humidity of 55% for 10 hours, then lowered to 36°C and 42% RH until equilibrium was achieved, for a total of 24 hours.

[0024] S2. Pre-irradiation treatment: The equilibrated dressing is transferred to an irradiation chamber, and nitrogen is introduced as an inert gas. The oxygen concentration is controlled at ≤200 ppm. Pre-irradiation is performed in this inert gas atmosphere. The irradiation dose is 6 kGy and the dose rate is 2 kGy / h.

[0025] S3. Main irradiation sterilization: Maintaining a nitrogen atmosphere, the irradiation dose is increased in stages. The first stage is irradiated at a dose rate of 1.2 kGy / h to a total dose of 9 kGy. A 3-hour rest period is provided between the two irradiation stages, during which nitrogen flow is maintained. The second stage is irradiated at a dose rate of 0.8 kGy / h to a total dose of 12 kGy.

[0026] S4. Post-processing: After irradiation, place in a 22°C environment for 48 hours and then transfer to sterile secondary packaging and seal.

[0027] Example 2

[0028] Reference Attachment Figure 1 The irradiation sterilization method of alginate dressing comprises the following steps:

[0029] S1. Preconditioning and equilibration: An alginate dressing with a molecular weight of 120 kDa and a calcium ion content of 12 wt% was packaged in a breathable primary packaging and placed in a constant temperature and humidity environment. The temperature was initially maintained at 43°C and 58% RH for 11 hours, then lowered to 37°C and 43% RH for 36 hours.

[0030] S2. Pre-irradiation treatment: Move the balanced dressing to the irradiation chamber, use argon as the inert gas, ensure that the oxygen concentration is ≤200ppm, and perform pre-irradiation. The irradiation dose is set to 5.5kGy and the dose rate is 1.8kGy / h.

[0031] S3. Main irradiation sterilization: Maintaining an argon atmosphere, irradiation is performed in stages. The first stage is irradiated at a dose rate of 1.3 kGy / h to a total dose of 8.5 kGy. After a 2.5-hour pause while maintaining argon flow, the second stage is irradiated at a dose rate of 0.7 kGy / h to a total dose of 13 kGy.

[0032] S4. Post-processing: After irradiation, the dressing is placed in a 20°C environment for 60 hours and then transferred to a sterile secondary package for sealing.

[0033] Example 3

[0034] Reference Attachment Figure 1 The irradiation sterilization method of alginate dressing comprises the following steps:

[0035] S1. Pretreatment equilibration: Encapsulate an alginate dressing with a molecular weight of 100 kDa and a calcium ion content of 10 wt% and place it in a constant temperature and humidity environment. Maintain the dressing at 40°C and 50% RH for 8 hours, then reduce the temperature to 35°C and 40% RH for a total of 12 hours.

[0036] S2. Pre-irradiation treatment: The balanced dressing is transferred into the irradiation chamber, nitrogen is introduced as an inert gas, and the oxygen concentration is controlled within the specified range for pre-irradiation. The irradiation dose is 7 kGy and the dose rate is 2.2 kGy / h.

[0037] S3. Main irradiation sterilization: Maintaining a nitrogen atmosphere, increase the irradiation dose in stages. In the first stage, irradiate at a dose rate of 1.0 kGy / h to a total dose of 10 kGy. After a 4-hour pause while maintaining nitrogen flow, irradiate in the second stage at a dose rate of 0.5 kGy / h to a total dose of 15 kGy.

[0038] S4. Post-processing: After irradiation, place the samples in a 25°C environment for 24 hours and then transfer them to sterile secondary packaging for sealing.

[0039] The working principle of the present invention is as follows: in the irradiation sterilization method of alginate dressing, the pretreatment balance link plays a key basic role. The dressing is placed in a specific constant temperature and humidity environment and a gradient adjustment method is adopted to change the water distribution state inside the dressing by regulating the temperature and humidity. As an important medium, the change in the distribution of water can affect the interaction mode between the free radicals generated during the irradiation process and the alginate molecules, reducing the damage of the free radicals to the molecular structure. In the pre-irradiation treatment stage, in an inert gas atmosphere, low-dose (5-7kGy) and low-dose rate (≤2.5kGy / h) irradiation causes partial cross-linking of the alginate molecules to form a cross-linked protective layer. This protective layer can buffer the irradiation energy in the subsequent main irradiation sterilization process to prevent the molecular chains from breaking due to excessive instantaneous irradiation doses. The primary irradiation sterilization is carried out in two stages. In the first stage, the irradiation dose is increased to 8-10 kGy at a relatively low dose rate (1.0-1.5 kGy / h). In the second stage, the dose rate is further reduced (0.5-1.0 kGy / h) to a total dose of 10-15 kGy. There is an interval between the two stages and the flow of inert gas is maintained. This gradual irradiation method allows the alginate molecules to gradually adapt to the increase in irradiation energy, further reducing the risk of molecular chain breakage while ensuring the sterilization effect. During the entire irradiation process, an inert gas environment (oxygen concentration ≤ 200 ppm) is maintained, which greatly inhibits the oxidation reaction caused by free radicals and prevents the alginate molecules from being oxidized and degraded. In the post-processing stage after irradiation, the unstable structure inside the dressing caused by irradiation is stabilized by standing at a specific temperature (≤ 25°C). Finally, it is transferred to a sterile secondary packaging and sealed to ensure the sterility of the dressing during subsequent storage and use.

[0040] The present invention regulates the internal moisture distribution of the dressing and reduces irradiation free radical damage through a specific temperature and humidity balance (not room temperature drying of the prior art). Experiments have shown that this condition can reduce the proportion of alginate crystallization area by 12%, improve irradiation stability, and create a unique "pre-irradiation + gradient main irradiation" two-stage mode: pre-irradiation (5-7kGy) forms a cross-linked protective layer at a low dose rate; the main irradiation is carried out in two stages to avoid instantaneous high doses that cause molecular chain breakage. Comparative experiments show that the molecular weight retention rate is increased from 68% of the conventional method to more than 92%, and the ultra-low oxygen environment (≤200ppm) is maintained throughout the irradiation process to inhibit free radical oxidation reactions. Compared with the air atmosphere, the viscosity loss rate of alginate is reduced from 22% to less than 5%.

[0041] The present invention and its embodiments are described above. Such description is not restrictive. The embodiment shown in the embodiment is only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the invention, without creatively designing a structure and embodiment similar to the technical solution, they shall fall within the scope of protection of the present invention.

Claims

1. A method for irradiation sterilization of alginate dressing, characterized in that: The following steps are involved: S1. Pretreatment equilibration: Place the alginate dressing encapsulated in the breathable primary packaging in a constant temperature and humidity environment, controlling the temperature to 35-45°C and the relative humidity to 40-60% RH for 12-48 hours; S2. Pre-irradiation treatment: Transfer the equilibrated dressing to the irradiation chamber and perform pre-irradiation under an inert gas atmosphere with an irradiation dose of 5-7 kGy and a dose rate of ≤2.5 kGy / h; S3. Main irradiation sterilization: Maintain an inert gas environment and increase the irradiation dose to 10-15 kGy in stages, including: In the first stage, irradiation was performed at a dose rate of 1.0-1.5 kGy / h to a total dose of 8-10 kGy; The second stage is irradiated at a dose rate of 0.5-1.0 kGy / h to a total dose of 10-15 kGy; S4. Post-processing: After irradiation, place in an environment ≤25℃ for 24-72 hours, and then transfer to sterile secondary packaging and seal.

2. The irradiation sterilization method of alginate dressing according to claim 1, characterized in that: In step S1, the constant temperature and humidity environment is adjusted by gradient: first, it is maintained at 40-45° C. and 50-60% RH for 8-12 hours, and then it is reduced to 35-38° C. and 40-45% RH and maintained until equilibrium is achieved.

3. The irradiation sterilization method of alginate dressing according to claim 1, characterized in that: The inert gas is nitrogen or argon, and the oxygen concentration is controlled at ≤200ppm.

4. The irradiation sterilization method of alginate dressing according to claim 1, characterized in that: The alginate dressing has a molecular weight of 50-150 kDa and a calcium ion content of 5-15 wt%.

5. The irradiation sterilization method of alginate dressing according to claim 1, characterized in that: In step S3, a 2-4 hour interval is provided between the two stages of irradiation, during which the inert gas flow is maintained.

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