Enzymatic assays for detecting lactose and sucrose in urine to reveal intravenous drug abuse with emphasis on buprenorphine

Abstract

Buprenorphine and methadone are commonly used medications for opioid maintenance treatment (OMT), using sublingual and oral administration, respectively. Although beneficial for OMT, these drugs can also be abused by intravenous administration. In intravenous abuse cases, the adjuvants lactose and sucrose are excreted in urine without hydrolysis to monosaccharides, since there are no disaccharidases in the blood. We validated enzymatic methods for the analysis of lactose and sucrose in urine. The analytical performance of both assays was considered appropriate for detecting intravenous drug abuse. The principle was proven by analyzing 93 postmortem (PM) urine samples for lactose, following comprehensive toxicological drug screening. In addition, 32 clinical urine samples from potential drug abusers were analyzed to assess the effect of PM changes on the assay. The mean level of lactose was low in clinical samples and relatively low in PM samples in which no drugs were found. Markedly elevated levels were seen in many of the buprenorphine positive samples, suggesting intravenous administration. Enzymatic methods could provide a simple and cost effective way to assess the intravenous administration of OMT drugs or drugs of abuse. Very high levels of glucose in urine may interfere with the assays. Furthermore, other causes for elevated urine disaccharides, such as hypolactasia and increased intestinal permeability, need to be considered in the interpretation of the results. Copyright © 2016 John Wiley & Sons, Ltd.

Enzymatic assay for urine lactose in the assessment of recent intravenous abuse of buprenorphine

“…In our previous study, we applied an enzymatic method to detect the disaccharides lactose and sucrose mainly in PM urine samples, and a correlation was found between lactose concentration and the presence of BPN or BNX. A similar enzymatic method had been previously used in the assessment of intestinal permeability of patients with hypolactasia, celiac disease, or inflammatory bowel disorders .…”

“…Lactose was analyzed as previously described . The enzymatic R‐biopharm Lactose/D‐Galactose kits were purchased from Roche (Darmstadt, Germany).…”

“…Parallel measurements were performed without the disaccharidase in the reaction to correct the effect of possible monosaccharides in urine. The limit of quantification (LOQ) for the lactose assay is 15 mg/L as previously described in the validation of the method for urine samples . For statistical analyses, values less than LOQ for lactose was reported as 15 mg/L.…”

“…Lactose was analyzed as previously described. 24 The enzymatic R-biopharm Lactose/D-Galactose kits were purchased from Roche (Darmstadt, Germany). The assay is based on the enzymatic hydrolysis of disaccharide to monosaccharides.…”

“…The limit of quantification (LOQ) for the lactose assay is 15 mg/L as previously described in the validation of the method for urine samples. 24 For statistical analyses, values less than LOQ for lactose was reported as 15 mg/L.…”