Clindamycin 1.0% - tretinoin 0.025% gel (CT Gel) is a reformulation of VELAC Gel that contains the same active ingredients (clindamycin 1.0% and tretinoin 0.025%) in a modified vehicle. This was a single-center, evaluator-blinded, randomized, placebo (vehicle)-controlled phase 1 study to evaluate the phototoxic potential of CT Gel using 24 hour single applications of 3 sets of 3 study patches. The study expected to enroll approximately 40 healthy adult volunteers. Each set of study patches consisted of a CT Gel patch, a vehicle gel patch, and a blank patch (did not contain CT Gel or vehicle gel). After concurrent 24-hour single applications of all 9 patches, 1 set of patches (set A) was removed, and those sites were irradiated with 16 joules/cm2 of ultraviolet A light (UVA) and 0.75 minimal erythema dose (MED) with UVA/ultraviolet B light (UVB). The second set of patches (set B) was removed, and those sites were irradiated with 16 joules/cm2 of UVA, 0.75 MED with UVB/UVA, followed by 15 joules/cm2 of visible light (VIS). The third set of patches (set C) was then removed, and those sites served as a non irradiated control. Inflammatory responses and other cutaneous effects were scored 1 hour after patch removal and during follow-up visits at 24, 48, and 72 hours after patch removal.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
37
Three CT Gel patches were concurrently applied to designated test sites by trained technicians and held in place with hypoallergenic tape. Patches were prepared no longer than 30 minutes prior to application to study subjects. A minimum distance of ¾ of an inch from patch pad to patch pad was maintained on a subject's back. Approximately 24 ±1 hours after patch application, test patches were removed by trained technicians. Patch sites were evaluated for signs of inflammation according to procedures.
Three vehicle gel patches were concurrently applied to designated test sites by trained technicians and held in place with hypoallergenic tape. Patches were prepared no longer than 30 minutes prior to application to study subjects. A minimum distance of ¾ of an inch from patch pad to patch pad was maintained on a subject's back. Approximately 24 ±1 hours after patch application, test patches were removed by trained technicians. Patch sites were evaluated for signs of inflammation according to procedures. 2. Vehicle gel contained the identical ingredients and packaging as CT Gel but without the active ingredients. All vehicle gel used during the study was from batch ZLU C.
Three blank patches were concurrently applied to designated test sites by trained technicians and held in place with hypoallergenic tape. Patches were prepared no longer than 30 minutes prior to application to study subjects. A minimum distance of ¾ of an inch from patch pad to patch pad was maintained on a subject's back. Approximately 24 ±1 hours after patch application, test patches were removed by trained technicians. Patch sites were evaluated for signs of inflammation according to procedures. 3. Occlusive patches consisted of a non-woven cotton pad (Webril \[approximately 2 cm x 2 cm\]) covered and secured on all sides by an occlusive hypoallergenic tape (approximately 4 cm x 4 cm).
Inflammatory responses (erythema and local skin reactions) or superficial effects (if observed) will be scored according to the erythema, local skin reaction, and superficial effects grading scales.
In cases where the patch area is larger than the irradiated area, only the irradiated areas will be scored unless reactions outside the irradiated area exhibit unusual responses. Scores represent the presence of clinically significant effects on at least 25% of the test site. Questionable, barely perceptible, or minimal reactions involving less than 25% of the test site will not be considered significant.
Time frame: 6 - 11 days
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