title: Can the behind-the-knee clinical test be used to evaluate the mechanical and chemical irritation potential for products intended for contact with mucous membranes?
abstract: BACKGROUND
  The behind-the-knee (BTK) clinical test system is being used increasingly to replace in-use clinical studies in the evaluation of potential irritation effects of consumer products. The objectives of these studies were to determine if the BTK test could adequately evaluate the potential to cause irritation for feminine protection products intended for mucous membrane contact, and confirm that the BTK test would not underestimate the irritant potential that may occur when products such as tampons come into contact with mucous membranes.
  
  
  METHODS
  Two identical tampon products were tested in in-use and BTK clinical studies. In the BTK clinical test, sites were scored daily 30-60 min after sample removal (PM scores with no recovery) and prior to application of the next sample (after 18 h of recovery). In the in-use clinical study, 6 sites (labia minora, introitus, lower and middle vaginal walls, upper vagina and cervix) were graded separately for erythema using colposcopy after use of each product for an entire menstrual cycle.
  
  
  RESULTS
  In the in-use clinical study, the labia minora were most susceptible to irritation effects with mean erythema scores (± SE) of 0.36 (± 0.05) and 0.50 (± 0.06) for the experimental and control products, respectively. All other sites produced a mean erythema ≤0.26. In the BTK clinical test, the postbaseline averages for erythema for the experimental and control products were 0.19 (± 0.04) and 0.20 (± 0.04) for the AM scores (with recovery), and 1. 25 (± 0.05) and 1. 27 (± 0.06) for the PM scores (no recovery).
  
  
  CONCLUSIONS
  Preliminary results showed that the BTK clinical test may be used to evaluate potential irritation effects of products that contact mucous membranes. In a first comparison of 2 tampon products in both the in-use and BTK clinical studies, the BTK protocol produced erythema reactions at the test sites that were similar to or severer than those observed on mucosal sites in the in-use study. Overall, the BTK clinical test showed a higher sensitivity, rapid turnaround time, higher flexibility and easier implementation. Thus, making the BTK clinical test a more useful tool for both safety testing and claim support.
authors.forename: Miranda A
authors.initials: MA
authors.lastname: Farage
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Miller
authors.forename: William J
authors.initials: WJ
authors.lastname: Ledger
mesh_terms: D003257:Consumer Product Safety; D018592:Cross-Over Studies; D004890:Erythema / Q000209:etiology; D005260:Female; D053566:Hygiene Products / Q000009:adverse effects; D006801:Humans; D007509:Irritants / Q000009:adverse effects; D007717:Knee; D052576:Menstrual Hygiene Products / Q000009:adverse effects; D009092:Mucous Membrane / Q000187:drug effects; D023422:Skin Irritancy Tests / Q000379:methods*
chemical_list: D053566:Hygiene Products; D007509:Irritants