volar surfaces of both forearms are alternately designated as either
the irradiated test arm or the non-irradiated control arm as test
subjects are empaneled. The non-irradiated arm serves to exclude possible
non-UVA-dependent dermal reactivity.
Approximately 0.2 mL or grams of each test article is applied to
test sites on each forearm using occlusive patches. Semi-occlusive
patches may be used when evaluating known irritating and/or volatile
hours later the patches are removed at the clinic, both test and
control sites are scored for dermal reactivity and the UVA-designated
sites irradiated with 4-5 Joules of UVA. Fresh patches are reapplied
to the same test sites. During Week 1 this procedure is repeated
daily (Tuesday-Friday) until 5 patch applications and 4 irradiation
exposures to the UVA-designated arm are completed. Patches applied
on Friday are left in place until Monday when the irradiation/reapplication
procedure is again repeated for a second week. During Week 2, patches
applied on Thursday are removed and scored on Friday. This 2-week
procedure results in a total of 9 induction patch applications and
8 induction irradiations.
a subject develops a level 2 reaction or greater during the Induction
phase, the patch is applied to an adjacent fresh site for the next
application. If a 2 or greater reaction occurs on the new site,
no further induction applications are made. However, any reactive
subjects will be subsequently patched/irradiated with the test article
on virgin test sites during the Challenge phase of the study.
an approximate 2-week Rest phase, fresh challenge patches are applied
to virgin test sites adjacent to the original irradiated and non-irradiated
test sites. Twenty-four hours later, the patches are removed from
the UVA-designated test area. The sites are gently wiped, examined
for any dermal reactivity and irradiated with the same UVA dosage
as the Induction phase. Following irradiation of the UVA-designated
test site, the control (non-irradiated) patches are removed, the
sites gently wiped and examined for dermal reactivity. The irradiated
and non-irradiated control sites are again scored, 24 and 72 hours
after irradiation. The test subjects are asked to report any delayed
reactions that might occur after the final challenge patch readings.
Skin Scoring Criteria
responses are scored according to the following 6-point scale:
No evidence of any effect.
perceptible) Minimal, faint, uniform or spotty erythema or tanning.
Pink, uniform erythema or tanning covering most of the contact
Pink-red erythema or tanning, uniform in the entire contact
Bright red erythema or tanning with/without petechiae or papules.
Deep red erythema with/without vesiculation and/or weeping or
edema (swelling) or other possible dermal sequelae are appropriately
recorded and described as mild, moderate or severe.
induction patches and 8 irradiations are made over a 2-week Induction
phase. There are no "rest" periods between induction patches.