Testing vaginal irritation with the Hen’s Egg Test-Chorioallantoic Membrane assay

Area of Science:

• Toxicology
• In Vitro Assays
• Medical Device Safety

Background:

• The Draize rabbit eye test is an in vivo method for assessing chemical irritancy.
• ISO 10993-10 suggests eye and vaginal epithelia irritation potentials are similar, allowing for alternative testing.
• In vitro methods are sought to replace animal testing for topical toxicity assessment.

Purpose of the Study:

• To evaluate the irritancy potential of vaginal formulations using the Hen’s Egg Test-Chorioallantoic Membrane (HET-CAM) assay.
• To establish an in vitro method for assessing vaginal product safety.
• To correlate HET-CAM results with known clinical data for vaginal irritants.

Main Methods:

• The HET-CAM assay was performed on marketed vaginal semisolid medicines, lubricants, a universal placebo, and Nonoxynol-9 (positive control).
• Assays followed the ICCVAM Recommended Test Method (NIH Publication No. 10-7553 – 2010).
• Formulations were classified using irritation scores (IS) via analysis methods (A) and (B).

Main Results:

• Marketed vaginal formulations demonstrated low irritation potential.
• Nonoxynol-9 was identified as a severe irritant at concentrations above 2%, aligning with clinical data.
• Analysis method (B) provided a more detailed classification of irritation.

Conclusions:

• The HET-CAM assay is a promising in vitro alternative for evaluating vaginal formulation irritancy.
• The assay shows potential for in vitro/in vivo correlation in toxicity testing.
• Further validation is recommended, but HET-CAM offers a viable prospect for vaginal irritancy testing without animal use.