Effect of Wuziyanzong pill on metabolism of dapoxetine in vivo and in vitro.

In vitro incubation of rat liver microsomes with 30 µL of 100 µmol·L-1 dapoxetine and 30 µL of 10, 100, 250, 500, 1000, 2500, or 5000 µg·mL-1 Wuziyanzong pill was performed at 37 °C for 60 min. Dapoxetine concentration was analyzed by high performance liquid chromatography (HPLC). The half maximal inhibitory concentration (IC50) of Wuziyanzong pill on metabolism of dapoxetine was 296.10 µg mL-1in vitro. Twelve SD rats were randomly divided into 2 groups: Control group and Wuziyanzong pill group. The two groups were administrated with 10 mL·kg-1 saline (Control group) or 10 mL·kg-1 Wuziyanzong pill solution (Experimental group, solution contained 200 mg mL-1 Wuziyanzong pill) for 15 consecutive days. Following administration of saline or Wuziyanzong pill on the 15th day, 20 mg kg-1 dapoxetine was administered to all rats. Blood was collected from the tail vein (0.3 mL) at multiple time points, and ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was used to determine the concentration of dapoxetine and its main metabolites, dapoxetine-N-oxide and desmethyldapoxetine in rats. Pharmacokinetic analysis of dapoxetine showed that area under the concentration-time curve (AUC) and mean maximum plasma concentration (Cmax) of the Wuziyanzong pill group were decreased, while plasma clearance (CLz) was increased compared with control group (P < 0.01). The HPLC method for determination of dapoxetine in vitro was accurate and specific. The UHPLC-MS/MS method established for determination of dapoxetine and its major metabolites in rat plasma was rapid and specific, which met the requirements of pharmacokinetic guidelines. Wuziyanzong pill had a weak inhibitory effect on metabolism of dapoxetine in vitro, but had a very strong induction effect in vivo, suggesting the dosage of dapoxetine should be increased when administered in combination with Wuziyanzong pill.

Linear polarization difference imaging and its potential applications.

We demonstrate a novel linear polarization imaging technique and its potential application in dermatology. This technique records a series of images corresponding to different combinations of illumination and detection polarization and calculates intensity differences between orthogonal detection polarizations pixel by pixel. Fitting the polarization difference data to an analytical expression of the incident and detection polarization angles results in two new parameters, G and (phi3)/2. It is shown that G is strongly correlated to the order of alignment of the fibrous structure in the sample, and (phi3)/2 represents the angle of orientation of the fibers. Preliminary clinical testing implies that this method may be applied for medical diagnosis of skin diseases.