High-performance thin-layer chromatographic determination of 5-methoxypsoralen in serum from patients.

A simple and rapid high-performance thin-layer chromatographic (HPTLC) determination of 5-methoxypsoralen in serum is necessary for the therapeutic survey of patients treated with Puvatherapy (psoralen+UVA). The assay for this biological fluid involves an extraction with heptane-dichloromethane (4:1, v/v). The analytical method is linear from 50 to 250 ng/ml. This assay range is adequate for analysing human serum, as it corresponds to psoralen concentrations measured in serum from patients treated with psoralen and UVA against psoriasis and vitiligo. The limit of detection is 15 ng/ml. The coefficient of variation was less than 7%.