OBJECTIVE To investigate the effect and mechanism of self-assembled nanoparticles from Shaoyao gancao decoction （SGD-SAN） on the intestinal absorption behavior of its main active components. METHODS SGD-SAN was prepared and characterized. Using an in-situ single-pass intestinal perfusion model in rats， the absorption characteristics of five active components （albiflorin， paeoniflorin， liquiritin apioside， liquiritin， glycyrrhizic acid） from SGD-SAN in the jejunum and ileum were studied， with the absorption rate constant （ K a ） and apparent permeability coefficient （ P eff ） as indicators， and compared with free drugs. In the intestinal segment with optimal absorption， the effects of drug concentration and efflux transporter inhibitors （P-glycoprotein inhibitor verapamil， multidrug resistance-associated protein 2 inhibitor indomethacin， breast cancer resistance protein inhibitor reserpine） on the intestinal absorption characteristics of these components were examined. RESULTS The obtained SGD-SAN exhibited a spherical shape with uniform sizes， an average particle diameter of （155.57±2.65） nm， a polydispersity index of 0.34±0.03， and a Zeta potential of （－9.30±1.12） mV. The average total content of five active components， including albiflorin， was 12.26%， and remained unaffected by enzymatic degradation and intestinal physical absorption. Compared with the free drug group， the five active components in the SGD-SAN group exhibited higher absorption rates in the ileal segment， with significantly elevated K a and P eff values （except for the P eff value of glycyrrhizic acid in the ileal segment） （ P ＜0.05 or P ＜0.01）. Their absorption demonstrated a concentration-dependent trend. In the free drug groups， the absorption of each component was regulated by corresponding inhibitors （ P ＜0.05 or P ＜0.01）； whereas in the SGD-SAN groups， except for albiflorin and paeoniflorin， the absorption of the remaining components was not affected by the inhibitors （ P ＞0.05）. CONCLUSIONS SGD-SAN significantly enhances the intestinal absorption efficiency of active components. The above absorption-enhancing effect may be related to the avoidance of efflux transporter influence and the presence of a mixed absorption mode.

Objective To explore the relationship between the peripheral dose and radioactive counts of 125I seeds detected by SPECT/CT.Methods Six 125I seeds(1.48×107 Bq, 1.85×107 Bq, 2.22×107 Bq, 2.59×107 Bq, 2.96×107 Bq, 3.33×107 Bq) were put into the solid water phantoms respectively. SPECT/CT was applied to scan the seeds. The radioactive counts (x) at the distance of 1-15 mm from the center of seeds were recorded respectively, while the corresponding doses (y, cGy) were calculated. SPSS 18.0 was used to analyze the relationship between the radioactive counts and peripheral dose. Results There was an exponential relationship between the peripheral dose of 125I seeds and the radioactive counts. The formula was as follow: y=507.849×1.004x. Conclusion SPECT/CT can visualize the peripheral dose of 125I seed, which may provide a method for dosimetric verification after brachytherapy.