Development and validation of a method for simultaneous separation and quantification of 5 different sugars in canine urine

The objective of this project was to develop and validate a method for concurrent separation and quantification of methylglucose, rhamnose, xylose, sucrose, and lactulose in canine urine by using high pressure anion exchange liquid chromatography and pulsed amperometric detection. The method was validated by evaluating dilutional parallelism, spiking recovery, intra-assay variability, and inter-assay variability. Observed to expected ratios for 3 urine samples, and all sugars, ranged from 77.6% to 106.9% for a 1:2 dilution, 85.2% to 121.4% for a 1:4 dilution, and 91.6% to 163.7% for a 1:8 dilution. Observed to expected ratios for spiking recovery of 3 urine samples, all sugars, and 5 different spiking solutions, ranged from 85.5% to 116.7 % (mean ± SD, 100.5 ± 6.0%). The intra-assay coefficients of variation were 1.6%, 3.4%, and 4.7% for methylglucose; 1.6%, 2.0%, and 3.6% for rhamnose; 2.7%, 1.4%, and 1.1% for xylose; 9.8%, 3.4%, and 4.0% for sucrose; and 3.2%, 3.3%, and 3.3% for lactulose. Inter-assay coefficients of variation were 3.2%, 5.7%, and 4.2% for methylglucose; 4.3%, 5.4%, and 6.4% for rhamnose; 3.3%, 5.0%, and 4.2% for xylose; 9.4%, 9.9%, and 9.4% for sucrose; and 6.1%, 4.9%, and 2.7% for lactulose. In conclusion, a method for simultaneous separation and quantification of 5 sugars in canine urine was established and found to be linear, accurate, precise, and reproducible. This method may prove useful in the simultaneous evaluation of gastric permeability, small intestinal permeability, and small intestinal mucosal function in dogs with gastrointestinal disorders.