The World Health Organization defines sterility as the absence of any viable microorganism. The problem with this definition is that such conditions would be too harsh for the existence of any active ingredients. For purposes of pharmaceuticals, a sterile container or environment is one in which the chances of it being contaminated by replicating organisms is less than 1 out of 1,000,000. Since it is not practical to open all medical containers for testing, sampling is usually done for sterility testing.
Sterility testing is anything but an easy task and that is why it is performed by highly qualified laboratory practitioners. It is the process by which any false positive results are completely eliminated as a means of achieving sterilization validation and quality control. False positives are usually as a result of laboratory contamination or even human error. It is imperative to design the test environment meticulously so as to meet the United States Pharmacopeia requirements. These requirements spell out the acceptable surface and microbial air counts. Any growth media used in the sterility testing must be carefully prepared to enhance microbial growth.
Sterility testing is a very important facet in pharmaceutical production since it ensures that only sterile products are released into the market. Understanding what this process entails is very beneficial since it helps in the process of validation. The process for creating samples, testing and subsequent follow-up tests must be clearly outlined in the stability protocols.
At the bare minimum, testing is incorporated as part and parcel of the stability protocol not only at the initial release point but also as at the final testing point. However, the FDA recommends additionally testing to be carried out regularly, e.g. annually, to ensure the products continue to adhere to the guidelines of sterile product protocols.
Even before an actual test is done, it is important to send a sample to the appropriate laboratory to ensure the lab determines all the important testing procedures beforehand. It is a good idea for every pharmaceutical company to develop different procedure specifications for testing their different products. A good procedure ought to be straight to the point and also clearly spell out which syringes or vials need to be tested.
Since medical paraphernalia come in various sizes and shapes, it is often not easy to entirely to test large medical devices. The workaround is defining a SIP (sample item portion). A SIP is just a small sample portion given in percentage of fractional terms. One of the greatest challenges of sampling is there is always a probability of not catching the infected containers.
In the last two decades, lots of advances have been made in all manner of sterility testing techniques aimed at making the tests more accurate and reliable. This has led to the introduction of molecular methods like nucleic acid amplification. In as much as broad testing is the preferred way of detecting unknown microorganisms, a couple of viruses can easily be screened by using targeted molecular methods. By and large, different techniques including the traditional direct inoculation and membrane filtration techniques, can be used in combination with nucleic acid amplification to ensure best results.