In the production of medical devices, the quality of process water (such as purified water and water for injection) directly relates to the safety and efficacy of the products. Therefore, standardized sampling of process water is a key step in ensuring that water quality meets the required standards. HeShuo Water Treatment will elaborate on the critical steps for sampling process water to help manufacturing enterprises improve the reliability of water quality monitoring.
**1. Classification of Process Water Types**
Based on usage and standard requirements, the process water needed for medical device production mainly includes:
1. Purified Water: Used for cleaning and preparing reagents, etc.
2. Water for Injection: Used for the final rinsing of sterile formulations or high-risk medical devices.
3. Other special process waters, such as condensate from sterilized steam, etc.
The quality standards for water vary based on different uses; therefore, sampling methods and testing items should be adjusted accordingly.
**Preparation Before Sampling**
- **Sampling Containers**: Use sterilized, stoppered glass or plastic bottles. For water samples requiring microbial limit testing, the containers must be pre-sterilized and well-sealed to prevent microbial contamination. Check for any visible damage or stains, and ensure that the stopper or cap is securely sealed.
- **Sampling Tools**: Prepare suitable tools such as stainless steel sampling spoons and sampling tubes. Sampling tools should be clean, dry, free of grease and impurities, and should be cleaned and disinfected before use, for example, rinsed with purified water and then wiped with 75% alcohol or subjected to moist heat sterilization.
- **Labeling and Record Forms**: Prepare sample labels containing details such as sample name, sampling location, sampling date, sampling time, sample number, production batch (if applicable), etc. Also, prepare a process water sampling record form to document detailed information during sampling, including environmental conditions, sampling personnel, sampling volume, etc.
**Selection of Sampling Locations**
- **Purified Water**: Samples should be taken from the total outlet, total return, and various usage points, such as water points in the production workshop and cleaning equipment water points.
- **Water for Injection**: Samples should be collected from the total outlet, total return, and critical usage points. Critical usage points include water points at preparation stations that come into direct contact with pharmaceuticals and water points for cleaning the inner packaging of terminal sterilized products.
- **Sampling Method**: For total outlets and return outlets, first open the sampling valve and allow water to flow for 2 to 3 minutes to flush out any impurities and residual water in the pipeline, then directly collect 500 to 1000 ml of water sample using the sampling container. Care should be taken to avoid splashing and contamination during sampling; quickly cover the container after sampling. For various usage points, select the method based on actual conditions. For tap-style outlets, first open to maximum flow, let water run, then adjust to a suitable flow before sampling; for spray-type outlets, place the container underneath to collect; for pipeline-style outlets, connect a sampling tube to the pipeline sampling valve and sample as per the method for total outlet and return outlet.
- **Sampling Volume**: For general physicochemical testing items, such as conductivity, pH, and heavy metal content, a sample volume of no less than 500 ml is required. For microbial limit testing, a sample volume of no less than 100 ml is needed; for water for injection, due to higher microbial limit requirements, it can be increased to 200 to 500 ml.
- **Sample Labeling and Sealing**: Apply a label with complete, accurate, and clear information on the outer wall of the sampling container. Seal the container securely; samples for microbial limit testing should be handled under aseptic conditions, and can be sealed with sterile sealing film or bottle caps to prevent leakage and contamination.
- **Sampling Records**: Sampling personnel must record the sampling location, time, volume, sample number, and any anomalies noticed during the sampling process, such as unusual water color or odor, pipeline leaks, etc., in detail on the form and sign to confirm.