Introduction
Standardisation of vaccines and sera means ensuring their quality, safety, purity and potency before use in humans. Vaccines stimulate active immunity by providing safe antigen exposure, while sera contain ready-made antibodies that provide passive immunity. Both must follow strict testing guidelines so that every batch is safe, effective and consistent.
Why Standardisation Is Important?
- To ensure vaccines and sera are safe for human use.
- To guarantee correct potency and protective action.
- To maintain consistency from batch to batch.
- To meet national and international regulatory requirements.
Toxicity Test
Toxicity testing checks for harmful or unexpected reactions. Vaccines used during pregnancy require additional care due to fetal safety. Toxicity tests help detect any toxic effect of the ingredients, adjuvants or preservatives.
Sterility Test
Sterility means complete absence of viable microorganisms.
- All injectable vaccines and sera must pass sterility testing.
- Tests are done at different stages of manufacturing and at final filling.
- Sterility test is based on detecting turbidity or microbial growth in suitable culture media.
- Methods follow pharmacopoeias like USP, BP and IP.
Potency Test
Potency represents the biological activity of vaccines or sera. It tells how effective the product is in producing immunity.
- Combination vaccines may require multiple tests due to different components.
- Each vaccine has its own method for potency testing, sometimes using animals or cell culture.
- Standard potency tests compare test samples with official reference standards.
Example: BCG Albumin Assay
The BCG albumin assay measures albumin concentration without pretreatment of samples such as serum, urine or biological preparations.
- Uses a single working reagent.
- Colour intensity at 620 nm is proportional to albumin level.
- Can be adapted for high-throughput automated systems.
Safety Test
The abnormal toxicity test (ATT) evaluates non-specific harmful reactions. It is done using mice and guinea pigs.
- This test ensures that the product does not cause unexpected toxicity.
- However, ATT may not always detect all unsafe batches, so modern regulatory systems use additional safety controls.
Endotoxin Test
Endotoxins are toxic components from gram-negative bacteria. Even small amounts can cause fever, shock or severe reactions.
- The Limulus Amebocyte Lysate (LAL) test is widely used for endotoxin detection.
- Many commercially available vaccines may contain small amounts of endotoxin if contamination occurred during processing.
- High endotoxin levels indicate contamination with gram-negative bacteria or their by-products.
Additional Components of Standardisation
1. Antigenic Content
Standardisation includes measuring the amount of antigen or antibody present in vaccines or sera. Accurate quantification ensures adequate immune response. Techniques include:
- ELISA
- Quantitative PCR
2. Potency Assays
Potency assays measure actual biological activity. They check how effectively the product can neutralise toxins or prevent infection.
- In vivo assays (animal models)
- In vitro cell culture methods
3. Stability Testing
Vaccines and sera must remain stable under recommended storage conditions. Stability tests include:
- Temperature variation studies
- Humidity tests
- Light exposure studies
These tests help fix expiry dates and storage guidelines.
4. Adjuvant Content
Some vaccines contain adjuvants that boost immune response. They must be accurately measured because:
- Too little may reduce vaccine effectiveness.
- Too much may increase side effects.
5. Safety Testing
Safety testing ensures absence of harmful contaminants, toxins or allergens. It confirms that each batch behaves similarly to previously approved batches.
6. Regulatory Compliance
Vaccine and serum standardisation must meet guidelines of regulatory agencies such as:
- Indian Drugs Controller (CDSCO)
- US FDA
- European Medicines Agency (EMA)
- WHO guidelines
Regulatory bodies set rules on manufacturing, quality control, labelling and storage.
Importance of Standardisation
- Ensures safe and effective immune protection.
- Maintains batch-to-batch uniformity.
- Builds public confidence in vaccination programmes.
- Prevents adverse reactions due to contamination or poor potency.
Detailed Notes:
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