Photoallergic Potential of 6% Bemotrizinol

The primary endpoint of this clinical trial is to evaluate the potential of Bemotrizinol (6%) to produce a photoallergic response.

The potential of 6% Bemotrizinol to produce a photoallergic response after application to the skin of human subjects followed by exposure to ultraviolet (UV) radiation will be assessed via the evaluation of a sunscreen oil with 6% BEMT and 10% ethanol as penetration enhancer (SU E 101413 85), as compared to a sunscreen oil vehicle with 10% ethanol as penetration enhancer without BEMT (SU-E-101413-82) and a dispersion of 6% BEMT in petrolatum (SU-E-101413-82).

Upon enrollment, a site on a subject's lower back, isolated from the actual test site, will be chosen to determine the subject's Minimal Erythema Dose (MED). The MED of each subject is assessed by applying a progressive geometric sequence of UV radiation exposures to five sub-sites, each of which is graduated incrementally by 25% over the previous site. The MED is evaluated 16 to 24 hours after ultraviolet radiation.

Duplicate test sites on the back (each approximately 4 cm2) will be identified. Test material will be applied to designated patches and affixed to both sides of the back. One side will be designated for irradiation, and the other is used as a treated/non-irradiated control. Approximately 0.15 g of each investigational product or vehicle controls will be applied to the fabric portion of separate patches with occlusive strips; an un-dosed patch will also be used.

Approximately 24 hours after application, the patches will be removed and the skin will be gently wiped. The MED will be determined from the five UV-treated sub-sites and all of the test sites will be evaluated according to the erythema grading scale. The sites designated for irradiation will be then irradiated with solar simulated light by two times an individual's MED.

The remaining site serves as the non-irradiated control. Test sites are delineated with a marking pen to ensure continuity of patch application and patch site location.

There will be three study phases associated with this study: Induction, challenge and re-challenge.

The induction phase procedure will be carried out twice weekly for a total of six applications/post-irradiation readings. However, the schedule may be modified to accommodate inclement weather, holidays, or missed applications. At the discretion of the Principal Investigator, the test material may then be applied, the sites irradiated and scored on two consecutive days during the Induction Phase. If a patch and or irradiation is missed, a 3-day sequence of patch/irradiation/score will be added at the end of the Induction Phase. Subjects must have no fewer than 5 evaluations at the end of the Induction phase. Only one rescheduled patch or irradiation procedure is permitted. Subjects missing a second visit are discontinued from the study due to non-compliance with the study protocol. For evaluation of photoallergy, during the Induction Phase, the sites are irradiated with 2 times the subject's MED (full spectrum wavelengths UVB 290-320 nm and UVA 320-400 nm) J/cm2 UVA. During the challenge phase, the sites will be irradiated with a dose of 10 J/cm2 of UVA light (320-400 nm) using cut-off filters to block UVB wavelength 290-320 nanometers.

Irradiated area within the treated sites and control sites are examined approximately 24 hours following irradiation of the test sites and graded. Skin condition of the sites will be evaluated at each visit for possible skin reactions to the test material. Any reaction will be documented on the source document.

If a 2+ reaction or greater occurs on a site, the application of the test material may be discontinued for the remainder of the Induction Phase, but may be challenged on the appropriate day of the study.

At the discretion of the Principal Investigator, subjects exhibiting a significant reaction at the beginning of the Induction Phase may be considered to be "pre-sensitized" to an ingredient(s) of the test product and may be discontinued from the patching and irradiation of that test material for the remainder of the study.

The challenge phase will occur approximately 10 to 21 days following the last induction application. Duplicate patches are applied to sites previously unexposed to the test material. In addition, 2 sets of patches without test material will be also applied on 2 sides of the back. Approximately 24 hours later, the patches are removed, the test sites are evaluated. The test sites on one side of the back are irradiated with a non-erythrogenic dose of Ultra Violet A (UVA) radiation (wavelengths 320-400 nm) equivalent to approximately 10 J/cm². The sites on the other side of the back serve as a "test material treated, non-irradiated" control site and "non-treated, non-irradiated" control. The challenge sites are graded at 24, 48, and 72 hours following irradiation according to the dermal grading scale.

A re-challenge phase may be initiated at the discretion of the Investigator, and with the Sponsor's approval. A subject may be re-challenged with the test material if reactions indicative of sensitization or photo sensitization are observed during the Challenge Phase. The subject(s) will be asked to return to the laboratory no sooner than two weeks following the conclusion of the PA study and the Challenge procedures will be repeated. One patch of the test material will be applied to the subject's back and allowed to remain in direct contact with the skin for 24 hours. The subject will return after 24 hours for removal of the patch and grading of the site, without irradiation if sensitization is suspected or with irradiation of an additional treated site (24 hour exposure) if reactions suggestive of photosensitization are observed during the study. Subjects will return for a 48 hour and 72 hour post-patch application grading and additional 96 hour evaluation if a reaction persists. If the sites are irradiated after patch removal, subjects will return for evaluation at 24 hour, 48 hour and 72 hour post UV exposure.