Bacterial Endotoxin (LAL) & Sterility Testing
Quantitative Kinetic Chromogenic Limulus Amebocyte Lysate (LAL) Pyrogen Assays and 14-Day USP <71> Microbial Culture for Injectable Peptides and Biologics.
Why Endotoxin & Sterility Testing is Essential
Bacterial endotoxins—lipopolysaccharides (LPS) shedding from the outer membrane of Gram-negative bacteria—are among the most potent pyrogenic contaminants known in biochemistry. Even when a solution is filtered and sterile, dead bacterial fragments can trigger severe immune reactions, fever, and anaphylactoid shock.
At Zenith BioChemical Laboratories HK, pyrogen quantitation is performed in positive-pressure ISO Class 7 cleanrooms using the Charles River Endosafe-PTS Kinetic Chromogenic LAL micro-fluidic system. By monitoring the enzymatic cleavage of a chromogenic substrate at 405 nm in real-time, our assays deliver precise quantification in Endotoxin Units (EU/mg or EU/mL) with positive product control (PPC) spike recovery verified between 50% and 200% according to USP <85>.
What the Safety Panel Encompasses
Dual-level evaluation assessing both biochemical pyrogens and live viable micro-organisms.
Kinetic Chromogenic LAL
Quantitative photometric determination of bacterial endotoxin concentrations from 0.05 to 10.0 EU/mL with internal standard calibration.
Aerobic & Anaerobic Culture
Direct inoculation into Fluid Thioglycollate Medium (FTM) incubated at 32.5°C for 14 days to confirm absence of viable bacteria.
Fungal & Yeast Culture
Inoculation into Soybean-Casein Digest Medium (SCDM) incubated at 22.5°C for 14 days to confirm zero growth of molds or yeast contaminants.
USP <85> & <71> Certificate
Official pass/fail certification documenting exact EU/mL values and turbidity clearance certificates for research and clinical records.
Safety & Pharmacopeial Threshold Matrix
| Parameter | Pharmacopeial Specification | Zenith Detection Threshold | Method |
|---|---|---|---|
| Bacterial Endotoxin (LAL) | < 5.0 EU / kg bodyweight / hr | < 0.05 EU/mL (Kinetic chromogenic) | USP <85> / EP 2.6.14 |
| Spike PPC Recovery | 50% – 200% recovery | Validated 85% – 115% nominal | Kinetic PTS cartridge |
| Anaerobic Bacteria | No growth after 14 days | Zero colony forming units (CFU) | USP <71> FTM @ 32.5°C |
| Fungi / Yeast | No growth after 14 days | Zero colony forming units (CFU) | USP <71> SCDM @ 22.5°C |
| pH & Osmolality | pH 4.5 – 7.5 (Parenteral range) | Mettler Toledo SevenDirect pH | USP <791> |
Submission Guidelines for Sterility
- Packaging: Must be submitted in an intact, hermetically sealed vial or ampoule with unbroken aluminum crimp seal.
- Aseptic Handling: Do not open or puncture rubber septa prior to shipment.
- Cleanroom Processing: Sample aliquoting is executed inside certified laminar flow biosafety cabinets (BSL-2).
- Reporting: Fast 3–5 day turnaround for quantitative LAL endotoxin; 14-day observation report for full microbial culture.