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Updated: Jun 10, 2025
Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate LAL Assays
Published on: January 30, 2019
Endotoxin Detection in Magnetic Resonance Imaging Contrast Agent Using Optimising Chromogenic Limulus Amebocyte
Atiqah Ab Aziz1, Sahrinanah Mappiare1, Hui Yin Nam1,2
1Tissue Engineering Group (TEG), National Orthopaedic Centre of Excellence for Research and Learning (NOCERAL), Department of Orthopaedic Surgery, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
Abstract:
Endotoxin contamination in magnetic resonance imaging (MRI) contrast agents can pose a risk to patient safety causing immune reactions. Strict endotoxin limits are enforced for implants and catheters inserted into the body, but there are not clear rules for MRI contrast agents. Here, we investigated the efficacy of chromogenic LAL assay test for screening endotoxin activity in MRI contrast media manufactured in Malaysia. The powdered agent was dissolved in water for injection and endotoxin levels were measured. The coefficient of efficiency value for the standard curve, exhibiting r 2 ≥ 0.98, along with the absence of interfering substances and endotoxin activity below the regulatory threshold of 0.5 EU/mL, support the conclusion that the agent is unlikely to be pyrogenic or induce pyrogenic effect.
Insights
This study validates the chromogenic Limulus Amebocyte Lysate (LAL) assay for detecting endotoxin in MRI contrast agents. Results show the Malaysian-manufactured agent is safe, with endotoxin levels below the regulatory limit, indicating no pyrogenic risk.
Area of Science:
- Medical Imaging
- Biotechnology
- Pharmaceutical Science
Background:
- Endotoxin contamination in medical products can cause adverse immune reactions.
- Existing endotoxin limits for implants and catheters are not clearly defined for MRI contrast agents.
- Ensuring the safety of MRI contrast media is crucial for patient well-being.
Purpose of the Study:
- To evaluate the effectiveness of the chromogenic Limulus Amebocyte Lysate (LAL) assay for screening endotoxin levels in MRI contrast agents manufactured in Malaysia.
- To determine if the tested MRI contrast agent meets safety standards regarding endotoxin contamination.
- To assess the pyrogenic potential of the MRI contrast agent.
Main Methods:
- The chromogenic LAL assay was employed to measure endotoxin activity.
- A powdered MRI contrast agent was reconstituted in water for injection.
- Standard curve efficiency (r² ≥ 0.98) and the presence of interfering substances were assessed.
Main Results:
- The chromogenic LAL assay demonstrated high efficiency with a standard curve coefficient (r²) of ≥ 0.98.
- No interfering substances were detected in the MRI contrast agent sample.
- Measured endotoxin levels were below the regulatory threshold of 0.5 EU/mL.
Conclusions:
- The chromogenic LAL assay is an effective tool for screening endotoxin in MRI contrast media.
- The investigated MRI contrast agent manufactured in Malaysia is unlikely to be pyrogenic.
- The study supports the safety of the tested agent based on endotoxin levels below the established limit.
