AIM: To explore the correlativity of the oil/water partition of hydroxycamptothecin and its absorp-tion coefficiency in small intestine in rats.METHODS: pH value of water phase in buffer solution in turn took 2.2,4.6,7.4,9.6 and 11,while octanol was adopted as oil phase.After phase equilibrium,HPLC was used to determine the concentration of hydro-xycamptothecin,and oil/water partition coefficient was calculated with the phenol red as volume calibration agent,small intestinal absorption coefficients of rats in different pH were plotted against its oil/water partition coefficients.RESULTS: Oil/water partition coefficient(x) of hydroxycamptothecin and small intestinal absorption(y) altered with the change of pH value of the dispension medium.The linear re-gress equation was constructed as y = 0.001 3x + 0.009 1 with its correlation coefficient R2 being 0.959 7.CONCLUSION: There exists a good linear dependence between oil/water partition coefficient of hydroxycamptoth-ecin and its absorption coefficient in small intestines of rats.Oil/water partition coefficient can be used to design the new oral preparations.

This paper explore the possibility of using the partition of 10-hydroxycamptothecin in the phases of liposome and water to predict the absorption of the drug in small intestine of rats. In order to certify this theory, the in vivo absorption model have been used to study the absorption of 10-hydroxycamptothecin in the small intestine of rats while altering the pH of the medium. The correlation has been explored between the partition of drug in the phases of liposome and water and the absorption of drug in the small intestines of rats. And it was found that the partition of 10-hydroxycamptothecin in the phases of liposome and water and the absorption of the drug in small intestines of rats altered with the changes of pH, and there existed a good relative coefficient between them. All of these indicated that partition of 10-hydroxycamptothecin in phases of liposome and water can be used to predict its absorption in small intestines of rats.
Animals ; Camptothecin ; analogs & derivatives ; chemistry ; pharmacokinetics ; Chromatography, High Pressure Liquid ; Hydrogen-Ion Concentration ; Intestinal Absorption ; physiology ; Intestine, Small ; metabolism ; Liposomes ; chemistry ; Rats ; Water ; chemistry