The intestinal absorption characteristics of five active components in Lizhong Decoction / 药学学报

The intestinal absorption properties of the main effective components (glycyrrhizic acid, isoliquiritigenin, 6-gingerol, ginsenoside Rb1, atractylode-I) in Lizhong decoction (LZD) extracts were investigated with an in situ single-pass intestinal perfusion model in rats. UPLC-TQ-MS was used to determine the concentration of the five components in the intestinal perfusion. Animal welfare and experimental procedures were in accordance with the regulations of the Animal Ethics Committee of Nanjing University of Chinese Medicine. As evaluation indexes for the intestinal absorption characteristics, the absorption rate constant (Ka) and the apparent permeability coefficient (Peff) of the five main ingredients were analyzed. Results showed that the best absorption sites for glycyrrhizic acid, isoliquiritin and 6-gingerol were the ileum, colon and duodenum, respectively, and the differences between different intestinal segments were statistically significant (P <0.05). There was no notable difference in Ka and Peff between ginsenoside Rb1 and atractylode-I in the different intestinal segments (P > 0.05), suggesting that they were absorbed throughout. The five components were well-absorbed in the whole intestine (Peff > 1.0×10-3 cm·min-1), indicating that LZD is suitable for preparing sustained, controlled release and enteric-coated preparations.

Absorption mechanism of three curcumin constituents through in situ intestinal perfusion method

This study aimed to investigate the absorption mechanism of three curcumin constituents in rat small intestines. Self-emulsification was used to solubilize the three curcumin constituents, and the rat in situ intestinal perfusion method was used to study factors on drug absorption, including drug mass concentration, absorption site, and the different types and concentrations of absorption inhibitors. Within the scope of experimental concentrations, three curcumin constituents were absorbed in rat small intestines through the active transport mechanism.

Absorption mechanism of SM-1：a procaspase-3-activated anti-tumor agent / 中国药理学通报

Aim To study absorption characteristics of SM-1 , a novel anti-tumor agent , to provide a research basis for the druggability evaluation of SM-1 and formu-lation design. Methods Caco-2 cell monolayer model and in situ single-pass intestinal perfusion rat model were used to study the absorption characteristics of SM-1 , and the absorption of SM-1 in vivo was evaluated through absolute bioavailability study in rats. Results The results of cell monolayer model showed that cu-mulative absorption and efflux of SM-1 increased line-arly with concentration ( 10 ~40 mg · L-1 ) . There were no significant differences in Papp with different concentrations ( P>0. 05 ) . SM-1 was absorbed mainly through passive diffusion. The intestinal perfusion re-sults showed that Ka and Pef of SM-1 had no significant differences ( P > 0. 05 ) , when the concentrations ranged from 25 to 100 mg · L-1 . SM-1 entered the systemic circulation mainly via on passive diffusion, indicating it is a compound with high permeability. The absorption of SM-1 in duodenum was superior to other intestinal segments ( P 0. 05 ) . The absolute bioavailability of SM-1 in rats was 29. 3%. Conclusion The membrane perme-ability of SM-1 is high and it can be absorbed by intes-tine well. The absorption mechanism of SM-1 is pas-sive diffusion, and it possibly escapes from the efflux transporter protein. The absolute bioavailability of SM-1 in rats is low.

Disposition of geniposide and genipin via intestinal absorption barrier / 中国药学杂志

OBJECTIVE: To study the disposition of geniposide and genipin via intestinal absorption barrier. METHODS: The biotransformation of geniposide was studied by incubating it with intestinal flora or intestinal enzymes. The intestinal absorption of genipin at duodenum, jejunum, ileum and colon was investigated using single-pass intestinal perfusion model. RESULTS: The metabolism activity of intestinal flora for geniposide was (1098.3±519.2) μmol · h-1 · g-1. The concentration of geniposide reduced from 20.00 to 9.60 μmol · L-1 after 4 h of incubation with intestinal enzymes, while the concentration of the metabolite of geniposide, genipin, increased to 3.52 μmol · L-1. The effective permeability coefficients(Peff*) of ginipin at duodenum, jejunum, ileum, and colon were 3.77±0.38, 3.00±0.20, 2.79±0.16, and 2.11 ±0.62, respectively, and the absorption percentages at different intestinal segments of 10 cm long(10 cm% ABS) were (70.24±7.88)%, (56.94 ±4.34)%, (53.44±3.73)%, and (48.52 ±9.59)%, respectively. There were significant differences between duodenum and the other regions of intestine of rats (P < 0.05). The phase II metabolite of genipin was found in rat bile, and its UV absorption spectrum was in accordance with that of genipin hydrolyzed by β-glu-curonidase. CONCLUSION: Geniposide can be transformed to genipin in rat intestine. Genipin can be well absorbed in general intestinal tract without specific absorption site. The phase II metabolite of genipin can be excreted to small intestine through bile.

Mechanism of in Situ Intestinal Absorption of Mangiferin in Rats / 中国药房

OBJECTIVE: To investigate the mechanism of in situ intestinal absorption of mangiferin in rats.METHODS: The in situ intestinal perfusion model was employed.HPLC/UV was developed to determine the concentration of mangiferin in intestinal circulated fluid.The effects of mangiferin concentration,bile and absorption site on the absorption parameters were studied.RESULTS:The mangiferin at a concentration from 5.0 to 25.0 ?g?mL-1 had no influence on the intestinal absorption kinetics(Ka) but it did at a concentration below 12.5 ?g?mL-1 in biliary duct-ligated rats.The absorption rate constants(Ka) in descending order were 0.164 h-1(ileum),0.132 h-1(jejunum),0.125 h-1(colon) and 0.107 h-1(duodenum),respectively.CONCLUSION: The absorption of mangiferin is in line with first-order kinetics with passive diffusion absorption mechanism.Mangiferin is well absorbed at all segments of intestine in rats,and bile is conducive to the increase of the permeability coefficient of Mangiferin in intestine.