A rapid gas-liquid chromatography method for the determination of lactulose and mannitol in urine: clinical application in studies of intestinal permeability.
OBJECTIVE
The purpose of this study was to develop a gas-liquid chromatography method for the determination of the urinary excretion of two nonmetabolizable sugars (lactulose and mannitol) to estimate the intestinal permeability.


METHODS
Two internal standards (alpha-methyl-D-glucopyranosyde and sucrose) were added to the urine samples prior to derivatization with the aid of a solution of pyridine, [N, O-bis (trimethylsilyl)]-acetamide and chlorotrimethylsilan. Sample preparation was simpler and faster than in other previous methods and the four sugars were resolved within 27 min.


RESULTS
The inclusion of internal standards reduced the coefficient of variation from 9.44% to 4.78%. The method provided better sensitivity, range of analysis, and linearity than a previously published HPLC method reducing variances in the recovery of lactulose and mannitol added to urine. The clinical application of this method was tested in preterm infants fed human milk or cow's milk based formula and in breast fed term infants.


CONCLUSIONS
The method described here for the determination of urinary lactulose and mannitol is more rapid, simpler, and more accurate than other previously published methods.
Martínez-Augustin
O
O
Department of Biochemistry and Molecular Biology, University of Granada, Spain.
Boza
J J
JJ
Romera
J M
JM
Gil
A
A
D002849:Chromatography, Gas / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007408:Intestinal Absorption / Q000502:physiology*; D007792:Lactulose / Q000652:urine*; D008353:Mannitol / Q000652:urine*; D010539:Permeability
D008353:Mannitol; D007792:Lactulose