Sterility testing is a crucial element of pharmaceutical manufacturing but testing for the absence of objectionable organisms in finished products is just the tip of the iceberg.
To ensure compliance to these harmonized methods, there are a host of validated, scientifically robust, product-specific protocols carefully designed to avoid the introduction of unnecessary risk. And building these standard operating procedures (SOPs) can be a complex, time- and resource-consuming challenge.
Sterility, USP 71 - and why it matters
Parenteral drug products, whether they are inhaled, ophthalmic, or intravenous, bypass many of the body’s natural defenses meaning they carry an increased risk of infection.
In 2012, for example, preservative-free MPA steroid injections were linked to more than 750 cases of fungal meningitis and other infections across the US in 20 states. More than 60 people died.[1],[2]
USP 71, which has been harmonized with its regulatory counterparts in Europe and Japan, aims to avoid such tragic consequences.
To comply, drug manufacturers must ensure their end products are completely free of objectionable organisms, including Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa, Aspergillus brasiliensis, Escherichia coli, Clostridium sporogenes, and Bacillus subtilis.
The regulation demands a 100% pass rate on a simple presence / absence test. Depending on the type of product (such as non-sterile or sterile) and the size of the batch, a set number of samples are incubated in both Fluid Thioglycollate Medium (FTM) and Soya Bean Casein Digest Medium (SCDM) (or Tryptic Soy Broth [TSB]) for 14 days.
Turbidity, a possible indicator of microbial growth, must be quantified, with any confirmed objectionable organisms leading to the delay or even the cancelation of release of the affected batch.
Delays are highly costly – both for return on investment and for the people who need access to their medicines. Manufacturers, then, must do everything in their power to make sure their products pass the test.
Structural support of compliance
Pharmaceutical laboratories must be confident that their own methods do not introduce risk – that any future contamination is an anomaly, rather than a trending consequence of the process.
To select the right approaches and tools for their SOPs, teams first must carry out suitability, or growth promotion tests, and validation, or bacteriostasis and fungistasis testing.
Suitability testing, during which laboratories find a media that would support the growth of target organisms within the product, is a process of trial and error. Next, that medium itself must be incubated and assessed for sterility.
Validation then ensures the product’s active ingredients are capable of killing the microorganisms, rather than simply inhibiting their growth.
Together, suitability and validation testing form the structural support of sterility testing strategies. These are highly specialized processes, requiring access to highly specialized tools.
Effective strategies
Pharmaceutical manufacturers know that robust sterility testing protocols are essential to protecting patient safety while keeping releases on time and on budget.
To build effective strategies, laboratories need skilled staff, regulated manufacturing standards, and access to a wide range of media, rinses, and quality control microorganisms.
- For more information on the Thermo Scientific sterility testing workflow, view our SmartNote>>
[1] https://www.cdc.gov/hai/outbreaks/meningitis-map-large.html
[2] https://www.cdc.gov/hai/outbreaks/meningitis.html
