ABSTRACT
<p><b>OBJECTIVE</b>To study the pharmacokinetics, distribution and excretion of m-THPC in rat models of liver cancer via orthotropic implantation using Walker-256.</p><p><b>METHODS</b>After an intravenous injection of m-THPC with 0.3 mg/kg, the concentrations of m-THPC in biological specimens were determined by a fluorescence method. The data obtained were processed with PK-GRAPH pharmacokinetic procedure.</p><p><b>RESULTS</b>The disposition of m-THPC in rat models of liver cancer Walker-256 was conformed to a two compartment model with T(1/2)α = 1.18 h, T(1/2)β = 22.57 h at the dose of 0.3 mg/kg.m-THPC was shown to be widely distributed to the various tissues. There was a highest drug accumulation in liver and liver cancer, and lowest in skin and muscle. Ratio of m-THPC concentration in the Walker-256 tumor compared to normal tissue reach the peak 24 h after m-THPC administration.</p><p><b>CONCLUSIONS</b>m-THPC is distributed widely and eliminated at a rapid rate in Walker-256 rats. Twenty four hours after m-THPC administration may be the best time for photodynamic therapy of liver cancer.</p>