GLP sterility testing for pharmaceutical products: methods, validation and nano-test solutions
Sterility testing is a crucial microbiological analysis to determine whether microorganisms living in sterile pharmaceutical products are present. In injection preparations, eye drops, infusion solutions, biological products and sterile medical devices, this test represents the last safety barrier for patient safety. lead sepsis.
Sterility tests conducted in the context of Good Laboratory Practice (GLP) ensure that the results are reliable, reproducible and acceptable to the regulatory authorities. In this article, we will cover the basic methods of pharmaceutical GLP sterility testing, validation requirements and the accredited services of Nano-Test in this area.
What is a sterility test and why does it have to be carried out within the framework of GLP?
A sterility test is performed to check the effectiveness of the product's sterilization process and to demonstrate that the final product does not contain live microorganisms. However, a sterility test alone does not guarantee that a batch is sterile; This guarantee is primarily guaranteed by the validation of the sterilization process or the aseptic manufacturing process. The pharmacopoeias expressly point out: The test does not replace the process validation, but supports it[Reference:0].
It is imperative to carry out sterility tests within the framework of the GLP for the following reasons:
- Data Reliability: The GLP sets strict regulations regarding personnel training, device calibration, standard work instructions (SOP) and data integrity (ALCOA+ principles).
- Authorized recognition: Authorities such as the FDA, the EMA and the TİTCK require GLP-compliant sterility test reports for approval applications.
- Documentation of aseptic conditions: It must be proven that the test was carried out under aseptic conditions and the environmental controls were regularly monitored[Reference:2].
Methods for sterility testing
Drug books (Ph. Eur. 2.6.1, USP <71>, JP) define two basic methods for sterility testing: Membrane filtration and Direct inoculation. The choice of method depends on the type of product and its physico-chemical properties.
1. Membrane Filtration Method
If the quality of the product allows filtration, the membrane filtration process is the preferred method[Reference:3]. In this process, the product is passed through a membrane filter with a maximum pore size of 0.45 µm; Microorganisms are retained on the filter, then the filter is transferred to a suitable nutrient medium and incubated.
Applications of application: Aqueous solutions, alcoholic or oil-containing preparations, products miscible with aqueous or oil-containing solvents.
In antimicrobial activity: If the product has antimicrobial properties, the membrane is washed at least three times; The washing cycle may contain a maximum of five washes of 100 ml per filter.
2. Direct Inoculation Procedures
In cases where membrane filtration is not suitable (e.g., non-filterable, viscous or particle-containing products), the direct inoculation method is used. In this process, the product is transferred directly to the nutrient medium[Reference:7]. It is suitable for products without antimicrobial activity or those in which this activity can be eliminated by dilution or inactivation.
3. Nutrient Media Used
The sterility test uses two basic culture media[Reference:9]:
- Fluid Thioglycollate Medium (FTM): It is primarily designed for anaerobic bacteria, but also detects aerobic bacteria.
- SOYBEAN-CASEIN DIGEST MEDIUM (SCDM): It is suitable for cultivating fungi and aerobic bacteria.
Incubation Conditions: for FTM 3 days at 32.5 ± 2.5 °C (in the aptitude test) or 14 days (in routine testing); For SCDM 5 days at 22.5 ± 2.5 °C (suitability) or 14 days (routine).
Comparison of sterility test procedures
The following table summarizes the two basic sterility test methods:
| Act | Principle | Suitable product types | Use in antimicrobial products | Advantages |
|---|---|---|---|---|
| Membrane filtration | The product is passed through a 0.45 µm filter; Microorganisms are retained in the filter and transferred to the nutrient medium. | Aqueous, alcoholic and oily solutions; filterable products. | The membrane is rinsed at least three times (max. 5 × 100 ml). | Preferred method; wide range of applications. |
| Direct inoculation | The product is transferred directly to the nutrient medium. | Non-filterable, viscous, particle-containing products. | The antimicrobial effect is eliminated by dilution or inactivation. | Alternative in cases where membrane filtration is not suitable. |
Validation of method suitability: The foundation stone of the sterility test
A sterility test is valid only if not only the correct method is selected, but it is also proven that this method is suitable for the product matrix. This validation, referred to as the "Method Suitability Test), confirms that the antimicrobial activity of the product is sufficiently suppressed under the test conditions.
Validation must be carried out in the following cases:
- If a new product is subjected to a sterility test,
- If changes are made to the test conditions,
- When the composition or manufacturing technology of the product changes.
In the validation test, the antimicrobial activity of the product is evaluated by observing whether the test strains (maximum 100 cFU) multiply in the presence of the product or not. If the test strains do not multiply in the presence of the product, this means that antimicrobial activity has not been canceled and validation must be repeated under modified test conditions.
GLP compliant sterility test services with nano test
Ensuring the sterility of your pharmaceutical products depends not only on the correct test method, but also on the fact that this test is carried out in an accredited laboratory according to the GLP principles and in a verifiable manner. Nano-Test is a reliable solution partner for the pharmaceutical industry with its comprehensive microbiological services in this area.
Nano-Test – Performance Description
Nano-Test offers GLP-compliant sterility tests (Sterility Test) for pharmaceutical products. Our analyzes are in full compliance with the PH. EUR. 2.6.1, USP <71> and ISO 11737-2:2019 carried out[Reference:15].
Our service portfolio:
- Membrane filtration process: The preferred method for filterable products; for antimicrobial products with suitable washing protocols.
- Directinoculation method: Alternative method for non-filterable products; Elimination of antimicrobial activity by dilution or inactivation.
- Validation of method suitability: Assessment of antimicrobial activity specifically for their product matrix and verification of method suitability.
- Nutritive media quality control: Confirmation of the growth-promoting properties of the culture media by Growth Promotion Test.
- Negative Control: Concurrently performing appropriate negative controls in each test series.
- Report: GLP-compliant, audited and regulatory-accepted reports.
All of our work is carried out under aseptic conditions, with data integrity (Alcoa+ principles) being guaranteed.
Advantages of the Nano Test sterility test:
- GLP accreditation: microbiology laboratory with OECD-GLP declaration of conformity.
- Pharmacopoeia Compliance: Full compliance with Ph. Eur. 2.6.1, USP <71> and ISO 11737-2 standards.
- Competence in two methods: Both membrane filtration and direct inoculation.
- Validation Support: Demonstrate validity of the test by a method validation tailored to your product.
- Fast reporting: Results on standard sterility tests within 3-5 working days after incubation.
- Specialist team: A team with experience in pharmaceutical microbiology and GLP validation.
The sterility test for pharmaceutical products is the final control authority for patient safety. Choosing the right method (membrane filtration or direct inoculation), the complete execution of method validation validation and the execution of the test under aseptic conditions according to the GLP principles are essential for the validity of the results and the official recognition.
With its pharmacopeia-compliant infrastructure, its GLP accreditation and its specialist staff, Nano-Test comprehensively meets the requirements of the pharmaceutical manufacturers for sterility tests. Collaborate with Nano-Test to document the sterility safety of your products and speed up your approval process.