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Objective: To study the rat intestinal absorption characteristic of puerarin loaded O-carboxymethyl chitosan (CMCS) microspheres in situ. Methods: Single-pass intestinal perfusion (SPIP) model was used for rat in situ and HPLC to determine the concentration of puerarin. The effects of different perfusion rate, drug concentration, and intestinal segments on intestinal absorption were investigated, and the absorption characteristics of the puerarin and puerarin loaded O-CMCS microspheres were compared. Results: Perfusion rate had significant effect on the absorption rate constants (Ka) and the apparent absorption coefficient (Papp) (P 0.05); Ka and Papp of drug loaded microspheres in jejunum and ileum showed no significant difference, but they were significantly higher than that in duodenum (P < 0.05); The drug loaded microspheres and puerarin had the significant difference in Ka and Papp in jejunum (P < 0.05). Conclusion: The absorption mechanism of puerarin in the microspheres is passive diffusion, puerarin is absorbed well in jejunum and ileum, and puerarin loaded O-CMCS microspheres can significantly improve the absorption of puerarin.
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Objective: Meglucumin cocrystal (MGC) is a new cocrystal compound which consists of curcumin with meglumine by hydrogen bond. The intestinal absorption parameter changes of MGC would be observed and be compared with curcumin. Methods: The intestine in rats was cannulated for in situ perfusion to study the absorption mechanism of MGC; UV was used to determine the concentration of MGC, to calculate the order of the absorption rate constants (Ka), and apparent permeability coefficients (Papp). Results: The Ka and Papp of MGC in the duodenum has significantly increased compared with the colon (P0.05) in other isolated regions of the intestine. The order was: duodenum>jejunum>ileum>colon; And that of Papp was: duodenum>jejunum>colon>ileum. The Ka and Papp in the whole intestine were (9.966±0.030)×10-3 min-1and (6.871±0.013)×10-3 cm/min respectively for the MGC which were 1.53 times and 2.21 times higher than these of curcumin. Conclusion: MGC is a better intestinal absorption characteristic than these of curcumin, suggesting that the bioavailability of MGC may be increased.
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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.
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duodenum, respectively. Conclusion The absorption of tetrandrine is first-order process with passive diffusion mechanism. Tetrandrine is well absorbed at all segments of intestine in rats.
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Objective: To investigate the characteristic of nasal mucosa absorption in vivo of tetramethylpyrazine hydrochloride (TMP HCl) in rats. Methods: The nasal circulatory perfusion test of TMP HCl was performed in rats.Results: The absorption rate constants was increased with the increasing of the concentration of TMP HCl; The absorption rate constants was increased with the elevating of pH values at the pH value range of 4.70～7.00. Conclusion:When the pH value of nasal circulatory perfusion liquid of TMP HCl is 7.00, the nasal mucosa absorption is optimal.