Test for Sterility of Medical Device

Sterility can be described as a condition where the presence of viable microorganisms is totally nil. This test can be used to determine the sterility condition of medical devices which have undergone sterilization processes such as ethylene oxide, gamma radiation, dry heat or steam.  As we know, the sterilization process will inactivate microbiological contaminants and thereby transform non-sterile items into sterile ones.  Sterility test therefore is performed as part of development, validation or requalification of sterilization processes to determine the presence or absence of viable microorganisms on product. The test method is based on the guidelines and annexes described in ISO document 11737-2 (2009).

The test must be conducted in a stringently controlled environment which should be as an aseptic as in a processing environment; and all instrument and apparatus used in the test must be sterile.

 

 

 

 

 

 

 


 

Upon request, we can work with you to select the most appropriate method for your particular product which usually is based on batch size, and advise you on how much of your product should be tested. SaniChem provides four types of sterility testing based on ISO and USP which are:
 

  • MB-STERIL-1: Direct immersion based on ISO  11737-2

  • MB-STERIL-2:  Direct Immersion based on ISO 11737-2  for Biological Indicator

  • MB-STERIL-3: Membrane Filtration based on ISO 11737-2  

  • MB-STERIL-4: Direct Immersion based on USP 71


 

Why we need to do sterility test?

Since contaminated medical devices may contribute to infection into human, thus performing sterility test on these devices can guarantee that they are safe for human use.

 


MB-STERIL-1(STERILITY TEST OF MEDICAL DEVICES: DIRECT IMMERSION METHOD)

Direct immersion is the most preferred method of performing the test of sterility for medical devices. With this method, the product unit or SIP(Sample In Portion is defined as part of a medical device product that is tested) is placed aseptically into a container of growth medium and incubated. A sufficient amount of growth medium should be used to achieve contact between the growth medium and the whole of the product unit or SIP.
 

 


MB-STERIL-2 (STERILITY TEST OF BIOLOGICAL INDICATOR FOR DIRECT IMMERSION METHOD)

This test is actually a test of sterility of biological indicators which have been exposed to a sterilization process. A biological indicator is a filter strip impregnated with test organisms that is known to be sufficiently stable in resistance to a specific sterilization process. Traditionally, the test organisms of biological indicators are bacterial spores, such as those derived from Bacillus or Geobacillus species. Biological indicator is used to validate the sterility process. They are included among the medical product samples, strategically at difficult to sterilize locations within the sterilizer chamber to test effectiveness of the sterilization cycle.



 

 

MB-STERIL-3 (STERILITY TEST OF MEDICAL DEVICES: MEMBRANE FILTRATION METHOD)

To detect and confirmed the absence of viable of microbes in or on medical devices. Cellulose nitrate filter with pore size of 0.45µm is used as membrane filter with aid of vacuum pump for filtration of any micro-organism still present in test article. Sterile water is used to extract microorganism from these large samples. Efficient extraction can be achieved with shaking or with help of ultra-sonication.


 

 

MB-STERIL-4 (STERILITY TEST OF MEDICAL DEVICES: DIRECT INOCULATION BASED ON USP<71>)

This test is used to determine the sterility of medical devices which have undergone gamma irradiation sterilization processes. The method is based on The United States Pharmacopeial Convention, USP 34, Microbiology Test/<71> Sterility Test, 2011. Soya-bean Casein Digest Broth (SCDB), also known as Tryptic Soy Broth, and Fluid Thioglycollate Medium (FTM) are used as growth medium as per recommendation of the USP procedures. SCDB is used to support growth of aerobic and fungi microorganism while FTM is used to support anaerobic microorganisms.   

 

 

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