Pharmacokinetics of 8-methoxypsoralen in serum and suction blister fluid.

Micronized 8-methoxypsoralen (8-MOP), with a smaller crystal size, produced significantly higher serum level profiles than nonmicronized 8-MOP. Furthermore, the absorption of the micronized drug was more rapid, resulting in peak serum levels within 1 h in 75% of the patients. Our blister fluid studies suggest, however, that reduction of the photosensitizer concentration is slower in skin than in serum. This implies that despite markedly reduced 8-MOP serum level after 2 h the skin remains sufficiently sensitized up to that point of time.