Sterilization | Sterility Assurance Level
"Sterilization" word itself explains its importance. In view of controlling microbial growth, it is the biggest important factor in pharmaceuticals. Much more time autoclave is widely used for steam-sterilization activities. In current industrial practices, more focus is given to sterilization practices. Hence it is very important to know about sterility assurance level and why it is important.
The main objective of the pharmaceutical industry is to provide safe, efficacious medicine to its patient. However, for injection and ophthalmic products sterility is the biggest product stability factor. As both the medicines are directly administered in the systemic circulation, hence inhibition of microbial contamination is the biggest concern, and pharmaceutical industries are spending a lot of money on the prevention of microbiological contamination toward the product's shelf life.
The sterilization process plays a great role in the prevention of microbial contamination in sterile dosage forms such as injection, ophthalmic products, etc.
Sterilization is the phenomenon of making objects/products free from microorganisms i.e. qualitative evaluation; wherein sterility assurance level is measuring unit for sterilization i.e. quantitative evaluation.
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Effectiveness of sterilization |
What is sterilization?
It refers to making objects free from microorganisms. This can be done by steam sterilization, depyrogenation, and by using chemicals, gases, etc.
What is the Sterility Assurance Level?
Sterility assurance level simply ensures that at how much depth the objects are free from microorganisms. It is extra assurance that there are no microorganisms that can contaminate the end products.
How sterility assurance level is measured?
As per study and regulatory guidance after 6 log reduction the products are said to be free from microorganisms. The 6 log reduction will give the confidence of sterility assurance level of 1 in 1 million chance. However, if we do an additional 6 log reduction i.e. 6+6= 12 log reduction it means there are a 1 in 1 million chance of microorganism can be killed which could lead to microbial contamination. this 12 log reduction is called a sterility assurance level of 10-6.
Normally sterilization is being done at 6 log reduction. at this concentration, the microbial population is killed. However, to meet the extra assurance the pharmaceutical companies are following an overkill approach i.e. 12 log reduction.
Detailed log reduction is explained below,
1 log reduction in microbial population means a 90% reduction in bioload.
For example;
If in a load, 100% bioload is present i.e. 1000000 microorganisms, then in 1 log reduction 90 microorganisms will be killed. There will be a 1 in million chance that can give microbial contamination.
|
Bioload (No. of
microorganisms)
|
Log of Spores
|
Log reduction
|
|
1000000
|
106
|
0
|
|
100000
|
105
|
1
|
|
10000
|
104
|
2
|
|
1000
|
103
|
3
|
|
100
|
102
|
4
|
|
10
|
101
|
5
|
|
1
|
100
|
6
|
|
0.1
|
10-1
|
7
|
|
0.01
|
10-2
|
8
|
|
0.001
|
10-3
|
9
|
|
0.0001
|
10-4
|
10
|
|
0.00001
|
10-5
|
11
|
|
0.000001
|
10-6
|
12
|
Sterilization process can be done by many methods, such as,
2. Dry heat
3. Radiation
4. Gaseous
5. Filtration
6. Chemical
Moist heat sterilization is a technique by which heat-labile products can be sterilized. The most important factor of this process is "steam". Hence, steam sterilizers are used for these activities.
2. Dry heat
This process is heat susceptible product. In this process, instead of steam, dry heat is used to kill or decontaminate the objects. Normally DHS (Dry heat sterilizer), ovens, tunnels are used for this process.
3. Radiation
In this process, the particles are exposed to gamma irradiation to complete the process.
4. Gaseous
5. Filtration
0.22-micron filter is used for filtration activities. As below this pore size, none of the microorganisms can cross the membrane.
6. Chemical
The chemicals like H2O2 (Hydrogen peroxide) are used for this method.
For a detailed review of sterilization methods, refer to below post.
1. Sterilization with Hydrogen peroxide
2. Science of sterilization
Conclusion:
Sterility assurance level is much more important to know the effectiveness of the sterilization process implemented.
Its very knowledgeable..!
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