QUANTITATION OF DEXTRAN-70 IN PERITONEAL DIALYSATE FROM PATIENTS ADMINISTERED 7.5-PERCENT POLYGLUCOSE

A method using gel permeation chromatography was evaluated for the qua ntitation of dextran 70 in dialysate samples containing polyglucose. D ialysate samples containing dextran 70 and polyglucose were pretreated using the enzyme alpha-amylase to selectively hydrolyze the alpha(1-4 )-linked polyglucose, white leaving the alpha(1-6)-linked dextran 70 i ntact. Following sample deproteinization with trichloroacetic acid, de xtran 70 was quantitated using gel permeation chromotography with refr active index detection. This method was evaluated for accuracy, precis ion, specificity, linearity, range, and analyte stability. Adequate me thod linearity with a correlation of >0.999 was established over the r ange of dextran 70 concentration from 1 to 0.025 mg/ml. Method precisi on was approximately 2% R.S.D. and accuracy (% recovery) was approxima tely 98-100% in the typical sample concentration range (1-0.5 mg/ml). This method was applied to the determination of intraperitoneal fluid kinetics in continuous ambulatory peritoneal dialysis (CAPD) patients administered daily night-time intraperitoneal exchanges with either 7. 5% polyglucose or 4.25% dextrose. Dextran 70 was added to the dialysis solutions to yield an initial concentration of 1 mg/ml. Dialysate sam ples were collected at various times over a 10-h dwell-time and assaye d for dextran 70. Intraperitoneal volume profiles based on dextran 70 concentrations and drain volumes were then calculated for each dialysi s solution. (C) 1998 Published by Elsevier Science B.V. All rights res erved.