As the name implies, medical grade water is purified water used in the medical field. It is primarily used to sterilise medical tools and other objects to kill bacteria, viruses, fungi, spores, and other microscopic organisms that they may have come in contact with.
Continue reading to find out more about what medical grade water is, how it’s purified, and its uses.
In this post:
Types of medical grade water
Medical grade water is basically a sterile purified water that has undergone reverse osmosis and deionisation processes.
There are various classifications based on regional standards, such as the European Pharmacopoeia (EP) and the United States Pharmacopeia (USP). These standards are very similar, with some subtle differences.
EP water
European Pharmacopoeia water is medical grade water suitable for sterilising medical instruments. It is a standard not only in Europe, but also elsewhere in the world. The specifications of this type of water are as follows:
- Conductivity < 5.1 microsiemens
- Nitrates < 0.2 ppm
- Heavy metals < 0.1 ppm
- Total Viable Count < 100
- Chlorides < 70 ppm
- Sulphates < 250 ppm
- pH range between 5 and 8
- Residue on evaporation < 100 ppm
USP water
US Pharmacopoeia water standards cover purified water suitable for medical and pharmaceutical uses based on US regulations.
These include USP Water for Injection (WFI), USP Purified Water, and Drinking Water. USP water for pharmaceutical manufacturing has the following specifications:
- Resistivity = 1.0–5.0 MΩ-cm
- TOC level < 500 ppb
- Bacteria count <10 cfu/100 ml
Comparing types of medical grade water
Medical grade water products are used for therapeutic, clinical, laboratory, and sterilising purposes. The EP and USP standards are the most common standards used for classifying medical grade water and are suitable for injections, pharmaceutical manufacturing, and laboratory analytical applications.
These water products are devoid of microorganisms but may still contain traces of impurities such as organic carbon. The medical grade water used for laboratory analysis is the purest.
Production and standards of medical grade water
The methods used for producing medical grade water typically include reverse osmosis, ion exchange, filtration, and UV treatment. Manufacturers follow standards based on local regulations and international industry standards such as the ISO 3696:1987 and ISO 22519:2023.
These standards and regulations cover the pretreatment, treatment, storage and packaging, and applications of medical grade water. Some products are suitable for injection, while others are more suitable for lab analysis.
Quality attributes for EP and USP water
Both EP and USP water are sterile and have a high level of purity. However, there are some minor differences in terms of the level of acceptable range of impurities.
The classifications are also subdivided into those used for laboratory applications, for injections, and for pharmaceutical manufacturing.
Regulatory compliance and certification processes
Regulatory compliance and certification processes slightly vary depending on the local laws and regulatory bodies. In the UK, for example, government agencies such as the Department of Health and Social Care, Scottish Government, Welsh Government or Northern Ireland Executive may have a say on regulations pertaining to medical devices and medical grade water.
The regulatory compliance and certification process usually involve the testing of products and inspection of the facilities where they are processed. Manufacturers of medical grade water are also required to submit technical papers and detailed documentation of their equipment and methods to secure a licence to operate.
Using medical grade water in healthcare
Aside from sterilising medical instruments such as scalpels, forceps, and retractors, medical grade water has other healthcare applications.
For example, it’s used in dialysis machines to run hemodialysis and peritoneal therapy. It is also essential in many clinical laboratory applications, particularly in assays and reagent preparations, and is also used in preparing injectable medicines such as mAbs and peptides.
Roles in medical device manufacturing
Medical grade water has a high level of purity and has no microorganisms. This makes it ideal for use on medical devices, such as those used in surgeries or one-time-use devices that require to be sterile, such as disposable syringes.
Pharmaceutical formulations
Similarly, pharmaceutical products, especially medicines, need to be sterile during the manufacturing process. The formulations of these products need to be highly precise as any contamination could ruin batches of products. Medical grade water ensures sterile and precise conditions.
Techniques used in medical grade water
Medical grade water undergoes strict processes under controlled environments mandated by regulatory agencies and based on international standards.
Purification techniques
Medical grade water usually undergoes several purification processes. First, the bacteria, viruses, fungi, and other organisms are killed and removed through distillation and UV irradiation.
Second, minerals and salts are removed through the deionisation process. Third, the water may further be subjected to reverse osmosis.
Regular monitoring
Ensuring the quality of medical grade water requires regular monitoring of both the equipment and the product itself. Both are subjected to tests and compared to the standards.
For example, the amount of total organic carbon is measured in the batches of newly processed medical grade water.
Quality assurance measures
Although both have the primary objective of improving quality, there are distinct differences between quality assurance and quality control.
In QA, the focus is the processes and procedures. These include documentation, training, equipment maintenance, monitoring, and audits. It’s preventive and proactive.
Meanwhile, quality control (QC) primarily focuses on checking the quality of the final product. Carefully complying with regulations and industry standards in manufacturing medical grade water is a crucial aspect of quality assurance.
Conclusion
Manufacturing medical grade water means following strict regulations and international standards, such as EP and USP standards. The water is subjected to different purification methods including reverse osmosis and deionisation. The level of purity is crucial, and is based on certain parameters, such as TOC, chlorides, and pH. Medical grade water is meant for use in the medical field, both for diagnostic and therapeutic purposes, and is also crucial in manufacturing pharmaceutical products.
