Beginner’s Guide with PLGA Sterilization

The sterilization process is a process that requires regular verification and key control in the production process of medical devices. The purpose of product sterilization is to make the product free of any type of surviving microorganisms. As the most used biodegradable polymer, PLGA also needs to be sterilization before use.

In this post, we will explain three common using methods, Including sterilization principles and influencing factors.

1. Ethylene oxide

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Ethylene oxide is a chemical substance. It is a colorless gas under normal temperature and pressure. It has a lively chemical property and can react with many substances.

When Ethylene oxide meets water, it reacts slowly to form ethylene glycol. Ethylene oxide has strong penetrating power and good diffusivity, it can penetrate packaging materials such as kraft paper, polyester film, polyethylene, and polyvinyl chloride film, which is beneficial to sterilization and preservation of articles.

The mechanism of action of ethylene oxide to kill various microorganisms is mainly alkylation, and the sites of action are thiol (-SH), amino (-NH2), carboxyl (-COOH), and hydroxyl in protein and nucleic acid molecules. (-OH) etc. Ethylene oxide can cause these groups to undergo an alkylation reaction, which makes microorganisms and biological macromolecules lose their activity, thereby killing microorganisms. 

The main factors of the ethylene oxide sterilization effect are temperature, concentration, humidity, sterilization time, etc. Since ethylene oxide sterilization is a chemical reaction, its reaction rate is related to temperature. It is not that the higher the temperature, the better.

On the one hand, considering the product’s resistance to temperature, on the other hand, excessively high-temperature requirements will increase the cost of sterilization equipment. Therefore, the most common sterilization temperature is about 50 ℃.

Humidity plays an important role in the ethylene oxide sterilization process. It is generally believed that the role of humidity has two aspects. On the one hand, the reaction of ethylene oxide with dehydrated bacterial spores requires a certain amount of water; on the other hand, water can enhance the environment. The permeability of oxyethane makes it easier to penetrate the packaging of medical devices.

2. Radiation

Radiation sterilization, also known as ionizing radiation sterilization, is based on radiation processing technology and uses high-energy rays generated by electric radiation such as x-rays, gamma rays, or high-speed electron beams to produce powerful physical effects in the process of energy transfer and transfer.

And biological effects, to achieve the purpose of insecticide, sterilization, and physiological processes.

The principle is mainly to destroy the DNA and RNA in the bacterial cells, the damaged DNA and RNA molecules are degraded, and the protein synthesis and genetic functions are lost, causing the cell to die.

Irradiation dose Sterilization dose refers to the absorbed dose that reaches the required sterilization assurance level (SAL), and the sterilization assurance level refers to the maximum expected probability that the product will be in a bacterial state after an effective sterilization process.

For radiation sterilization, the number of inactivated microorganisms follows the law of exponential inactivation. This means that no matter how big the dose is, the microorganisms have a corresponding chance of survival.

3. Moist heat sterilization

Moist heat sterilization can be divided into high-pressure steam sterilization, boiling, pasteurization, and ultra-high temperature sterilization.

The high-pressure steam sterilization method heats water to produce steam and uses the latent heat energy released by saturated steam to kill all microorganisms in the articles to be sterilized under specific conditions (pressure, temperature, time, etc.) through special equipment to achieve no The purpose of bacteria.

High-pressure steam sterilization has strong sterilization ability and is the most effective and widely used sterilization method in thermodynamic sterilization. Medicines, containers, culture media, sterile coats, rubber stoppers, and other items that will not change or be damaged when exposed to high temperature and humidity can all be sterilized by this method.


The three commonly used sterilization methods have corresponding limitations. Medical device companies can choose the best sterilization method based on product materials, packaging methods, and other unfavorable sterilization factors to improve the quality of products after sterilization and reduce costs.

Based on the above-mentioned sterilization theory, the influencing factors of the three polymer material medical device sterilization methods can be optimized, and the optimal sterilization process parameters can be determined.