OBJECTIVETo develop a spectral assay for determination of pachyman sulfate (PS) in rat plasma and to study the pharmacokinetics after intraperitoneal and intravenous administrations of PS.

METHODThe spectral probe azur A (AA) was used to measure the concentration of PS in rat plasma, since AA could combine the sulfate groups in PS molecules and consequently induced the color change in solution. The optimal wavelengths, concentrations of plasma and AA in reaction system were determined by spectral scanning and serial tests. The plasma PS concentrations were measured at different time after intraperitoneal and intravenous administrations at the dosage of 60 and 20 mg x kg(-1), respectively.

RESULTThe optimal detecting wavelength was 620 nm. The maximum concentration of plasma and the optimal concentration of AA were 1.25% and 8.24 x 10(-5) mol x L(-1) in reaction system, respectively. The calibration curve was linear over the range of 0-10 mg x L(-1) with a correlation coefficiency of 0.995 9. The mean recovery was 100. 55%. The relative standard deviation (RSD) of intra-group and inter-group were all less than 5%. After intraperitoneal and intravenous administrations, the corresponding elimination half-lives were 319.09 min and 204.85 min, respectively. The elimination of PS in blood matched the open model of one compartment and first-order elimination. The bioavailability of PS via intraperitoneal injection was 69.12%.

CONCLUSIONThe spectral probe AA was convenience, sensitive, accurate and steady to use for measuring the concentration of PS in the blood of rats; this made the research work of PS-pharmacokinetics easy and concise.