Photochemotherapy: a new promising chemical derivative.

A new synthetic psoralen (5'aminomethyl-4,4',8-trimethylpsoralen) is presented which possesses potential superior photochemotherapeutic efficacy. Results of studies conducted on the guinea pig and hairless mouse in our laboratories reveal that following oral administration there is a more rapid onset of photosensitization, a more rapid loss of photosensitization indicating apparent chemical inactivation or excretion, and a lower systemic toxicity on a milligram to milligram basis when compared to conventional psoralen derivatives. These results indicate that the use of this new derivative will minimize potential side effects such as ocular complications and inadvertent additional photosensitization that might lead to premature aging and carcinogenesis due to the slow onset and prolonged photosensitization following administration that are characteristic of conventional psoralen derivatives.