RecruitingPhase 1Drug trialTesting Use of Topical Imipramine in Reducing Ultraviolet B Induced Microvesicle Particle Release in Photosensitive SubjectsThe purpose of this study is three-fold. First, researchers will assess whether subjects who have clinically abnormal reactions to sunlight (photosensitivity) have increased levels of microvesicle particles (MVP) following ultraviolet B (UVB) treatment to localized area of skin. Second, researchers will assess if topical application of the medicine imipramine will block UVB-induced MVP release. Third, researchers will assess if the topical cream will block UVB-induced increased erythema reactions (reddening of the skin).