title: Determination of trimethylpsoralen in blood, ophthalmic fluids, and skin.
abstract: Trimethylpsoralen (TMP) levels in the blood of vitiligo patients were determined through the use of a high-performance liquid chromatographic method. TMP was extracted from blood buffered at pH 9.0 with 95:5 (V/V) hexane-isopropanol mixture; evaporated to dryness, and reconstituted in 50 microliters of ethanol. A 10-microliters aliquot was injected into a Micropack MCH-10 column (Varian HPLC model #5000). The mobile phase consisted of a mixture of water and acetonitrile with a linear gradient. The retention time of TMP was 16.5 min. The calibration curve of the external standards was linear. Overall recovery of the internal stands was 75-92%, with the lower detection limit of TMP at 2 ng/ml. Peak blood levels as low as 140 ng/ml and as high as 800 ng/ml were obtained in vitiligo patients 1-2 hr following the oral administration of 30 mg of trioxsalen tablets (Paul B. Elder Co.). Blood TMP levels peaked consistently at 2 hr when patients were fasted for 8 hr prior to drug ingestion. These results are consistent with the clinical observation that maximum response due to phototherapy is obtained 1-2 hr after oral administration of the drug. Two hours after oral drug administration, TMP levels in the epidermis, dermis, and whole skin of the guinea pig (in ng per g tissue) were: epidermis, 226 +/- 15; dermis, 25 +/- 6; and whole skin 176 +/- 12. Also detected were TMP levels 244 +/- 17 ng/ml in aqueous humor and 63 +/- 6 mg/ml in vitreous humor. These results point to the fact that the eyes of patients must be protected from overexposure to sunlight after psoralen-ultraviolet treatment.
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000818:Animals; D001082:Aqueous Humor / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005260:Female; D011564:Furocoumarins / Q000032:analysis*; D006168:Guinea Pigs; D006801:Humans; D008297:Male; D008875:Middle Aged; D011701:PUVA Therapy / Q000009:adverse effects; D012867:Skin / Q000032:analysis*; D013997:Time Factors; D014307:Trioxsalen / Q000008:administration & dosage / Q000032:analysis* / Q000097:blood; D014820:Vitiligo / Q000378:metabolism / Q000628:therapy
chemical_list: D011564:Furocoumarins; D014307:Trioxsalen