Water Immersion Studies of a Long-wear Sunscreen to Improve Protection Against Ultraviolet Radiation
Condition: Sunburn
MeSH terms: Sunburn
Study type: Interventional

Summary: 
      This study is designed to determine the Sun Protection Factor (SPF) of a test product
      following 80 Minute Water Immersion methodology defined in Final Monograph - Code of Federal
      Regulations Title 21 - "Labeling and Effectiveness Testing; Sunscreen Drug Products; Required
      Labeling Based on Effectiveness Testing", Final Rule, 21 CFR 201.327.(j)
    

Detailed description: 
      All studies will be carried out in a blind fashion according to FDA guidelines, which
      describes the number of subjects required to satisfy FDA guidelines and labeling requirements
      of sunscreens. Human subject selection: Healthy volunteers (n=25) free from systemic or
      dermatological disorders of Fitzpatrick skin type I, II or III (12 male and 13 female; ages
      18 through 55) will be recruited. Rectangular test sites of (30 cm2) on the infrascapular
      area of the back will be delineated, and inspected to ensure uniform pigmentation, skin tone
      and texture, and absence of warts, moles, nevi, scars, blemishes and active dermal lesions.
      SPF determination: A 150 W Xenon Arc Solar Simulator, which produces a continuous UV spectra
      substantially equivalent to that of natural sunlight will be used and UVB radiation monitored
      continuously. Measurements will be recorded within 8 mm from the surface of the skin, and the
      size of the exposure site will be ≥ 0.5 cm2. The Sunscreen or a positive control (8%
      homosalate) will be applied to subjects evenly in the delineated areas at 2 mg/cm2. Following
      static exposures, test sample and water resistant controls will be applied on adjacent sites
      for testing. An unprotected site will receive a series of five UV exposures based upon the
      previously determined Minimal Erythemal Dose (MED). The UV exposures for each formulation,
      will be calculated from previously determined MED and the intended SPF. Immersion procedure:
      Immersion will be conducted in a whirlpool tub with room temperature water circulating at
      3450 r.p.m. Following pre-immersion SPF measurements, volunteers will be subjected to 80 min
      of whirlpool immersion, with SPF measurements taken after air drying at 20, 40, and 80, min.
      c. Data Analysis and Interpretation: The 80 min time point is chosen as a benchmark for
      success because the FDA only permits finished sunscreen products to be labeled as water
      resistant for up to 80 min. All subjects will return to the laboratory sixteen to twenty-four
      hours post-exposure for a blinded determination of erythema responses, the mean SPF, standard
      deviation (s) value, and standard error (SE). No attempts to determine the influence of sex
      or age on the interpretation of results will be undertaken because of Phase I SBIR budgetary
      and time limitations, and because this is not a requirement of FDA or customers /
      distribution partners who will purchase the product. The standard deviation (s) will be
      determined and the upper 5% point was obtained from the t distribution table with n-1 degrees
      of freedom (t).
    

Intervention name(s): Sunscreen -R43
Intervention type(s): Other
Intervention description(s): Long wear metal oxide particles
Intervention MeSH terms: Sunscreening Agents
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Prevention