About Levan: Safety
Polysaccharides are generally safe materials for both users and the environment. Although first discovered over 100 years ago and subjected to many laboratory studies, no reports of adverse effects have been found.
NO OCULAR IRRITANCY: Ocular irritancy tests have shown levan is safe for use near the eye.
Chorioallantoic Membrane Vascular Assay (CAMVA 14 day)
- RC50 >3.0% = Non-irritant
- RC50 >1.0% <3.0% = Indeterminate
- RC50 <1.0% = Irritant
Interpretation: CAMVA tests are conducted on egg chorioallantoic membranes. A higher number denotes less irritation. At 87% (well above the 3% threshold for a non-irritant), the CAMVA test indicates levan is not causing irritation.
Bovine Corneal Opacity and Permeability Test (BCOP)
- 0-25 = Mild irritant
- 25.1 - 55 = Moderate irritant
- 55.1 and above = Severe irritant
Interpretation: For this test, a lower number points to less irritation. The BCOP score of minus 0.94, indicates marginally less irritation for corneas treated with levan than the saline controls.
NO DERMAL IRRITATION OR ALLERGIC CONTACT SENSITIZATION: A Human Repeat Insult Patch Test (HRIPT) on 50 people had zero scores, indicating that levan does not cause dermal irritation. Upon administration of challenge doses there was no indication of allergic contact sensitization.
NO CYTOTOXICITY: Levan is not cytotoxic in the Agar Diffusion Test.
BIODEGRADABLE PLASTIC: In a marine biodegradation test, it was found that 60% of levan was mineralized in 10 days.