Cellulose derivatives and intestinal absorption of water and electrolytes: potential role in oral rehydration...

The physicochemical and structural characteristics of several types of carboxymethylcellulose (CMC) and of methylcellulose (MC) were examined in relation to their capacity to modify water and sodium absorption in oral rehydration solutions (ORS) at various concentrations, using a jejunal perfusion procedure in rats. Comparison of intrinsic low-viscosity CMC of various degrees of substitution (DS) revealed that net water absorption increased as the DS was augmented. A stimulatory effect on sodium absorption occurred only at a low (2.5 g/l) CMC concentration. With products of medium DS, stimulation of net water and sodium absorption was observed only with low-viscosity CMC at 2.5 g/l, but not at 5.0 g/l. In perfusions with CMC of medium and high DS there was a reduction of water and sodium absorption, ultimately resulting in net sodium secretion with 5.0 g/l high-DS CMC. MC perfused at 5.0 or 10.0 g/l reduced net water absorption and reversed sodium transport from absorptive to secretory status. These results show that while low-viscosity-grade, low-DS CMC in low concentrations may facilitate solute uptake and concurrent water absorption from ORS by the jejunum, high intrinsic viscosity and possible chemical interaction of solutes with the modified celluloses tend to block water uptake and produce fluid stasis and electrolyte secretion. Thus, the data suggest that only certain types of CMC may be proabsorptive when added to ORS, while high-viscosity and high-DS CMC or MC induce electrolyte malabsorption and eventual catharsis.