Determination of 5,10,15,20‐ tetra‐ ( m ‐hydroxyphenyl)chlorin in human plasma by high performance liquid chromatography

A high performance liquid chromatographic method for the determination of the photodynamic chemotherapeutic agent 5,10,15,20‐tetra( m ‐hydroxyphenyl)chlorin (m‐THPC) in human plasma following intravenous infusion is described. The procedure involves extraction of the drug in plasma with methanol/dimethyl sulphoxide (4:1 v/v) containing 5,10,15,20‐tetra( p ‐hydroxyphenyl)clorin as the internal standard and separation on a C18 reversed phase column with acetonitrile:0.1% trifluoroacetic acid (77:23 v/v) as the mobile phase. The drug was detected specifically and sensitively at its absorption maximum of 423 nm with a detection limit of 15 ng/mL (signal‐to‐noise ratio of 5). The intra‐ and inter‐assay coefficients of variation (CV) on analysis of a plasma spiked with m‐THPC (1 μg/mL) were 2.3 and 3.4% ( n =6), respectively.