Effect of anionic macromolecules on intestinal permeability of furosemide

Context: Furosemide is an anionic molecule and has very low absorption in gastro intestinal tract. Objective: The aim of this study was to investigate the effect of anionic macromolecules on the intestinal permeability of Furosemide. Materials and methods: The intestinal permeability of Furosemide was determined using single-pass intestinal perfusion technique in rats. Briefly a jejunal segment of similar to 10 cm was isolated and cannulated in both ends for inlet and outlet solution. The perfusate was collected every 10 min and samples were analyzed using the RP-HPLC method. Test samples containing furosemide and two anionic macromolecules, sodium carboxy methyl cellulose and sodium alginate, at different concentrations were used. Results: The obtained data showed that existence of Sodium carboxy methyl cellulose significantly increased the P-eff values in all three investigated concentrations (p < 0.05) but sodium alginate only in concentrations <0.1% increased drug permeability. Discussion: It is concluded that the anionic macromolecules at specific concentrations could alter the permeability of anionic drugs across the biological membranes. Conclusions: Donnan phenomenon and chelating property of macromolecules could be attributed to the observed effect.