Evaluation of Saccharin and Resveratrol as Extrinsic Markers of Small-Quantity Lipid-Based Nutrient Supplement Consumption in Healthy Women

BACKGROUND

Dietary supplements, like small-quantity lipid-based nutrient supplements (SQ-LNS), are used in intervention programs to prevent undernutrition among women and young children in low-income countries. An objective marker is needed to track consumption of supplements to evaluate the effectiveness of these programs.

OBJECTIVE

The aim of this study was to evaluate saccharin and resveratrol as potential adherence markers for tracking recent consumption of a single serving of SQ-LNS in women.

METHODS

Forty-seven healthy nonpregnant women 18-45 y of age were assigned to consume a single dose of SQ-LNS (20 g) containing either 10 mg sodium saccharin or 5 mg trans-resveratrol, under supervision. On the day before and for 2 d following SQ-LNS consumption, urine samples were collected each day for 24 h as 3 consecutive 4-h collections and one 12-h overnight collection. Urinary concentrations of saccharin and trans-resveratrol-3-O-sulfate, a resveratrol metabolite, were measured by ultra-high-performance liquid chromatography interfaced to a mass spectrometer with electrospray ionization [UHPLC-(ESI-)MS/MS]. Urinary concentrations (μmol/L urine) of saccharin and trans-resveratrol-3-O-sulfate were plotted against time, and receiver operating characteristic (ROC) curves were used to determine the discriminative capacity of each compound, at each post-consumption time point compared with baseline, to detect recent consumption of SQ-LNS. Cutoff values to differentiate supplement consumption from nonconsumption of each marker were developed using the closest-to-(0,1)-corner cut-point approach.

RESULTS

Forty-five participants were included in the analysis. Urinary concentrations of saccharin and trans-resveratrol-3-O-sulfate increased within 4 h of SQ-LNS consumption. Urinary concentration cutoff values for saccharin (13.4 µmol/L) and trans-resveratrol-3-O-sulfate (0.7 µmol/L) allowed for 78% and 89% sensitivity, respectively, and 100% specificity in detecting consumption of SQ-LNS within the first 12 h after consumption.

CONCLUSIONS

Urinary concentrations of saccharin and trans-resveratrol-3-O-sulfate reflect consumption of SQ-LNS containing those compounds during the first 12 h post-consumption with high sensitivity and specificity in healthy women and may be useful objective adherence markers for tracking consumption of SQ-LNS.

Measurement of Saccharin and trans-Resveratrol Metabolites in Urine as Adherence Markers for Small Quantity Lipid-Based Nutrient Supplement Consumption

Saccharin and trans-resveratrol were incorporated into small quantity lipid-based nutritional supplements (SQ-LNS) to be evaluated as the markers of consumption for nutritional intervention studies. Forty-seven healthy women consumed a single supplement with either 8.6 mg of saccharin or 5 mg of trans-resveratrol, and urine was collected for 4 h. A rapid 11 min method employing multiple reaction monitoring and ultrahigh performance liquid chromatography coupled to a triple quadrupole mass spectrometer was developed to measure saccharin and resveratrol metabolites in urine simultaneously. The linear dynamic range of the method was from 3 to 1000 ng mL^-1, with the correlation coefficient of 0.999 and limits of quantification from 15.28 to 53.03 ng mL^-1. Sample preparation was simple dilution with an average recovery of 97.8%. Ion suppression was observed with urine concentrations >10%. Mean levels of saccharin and resveratrol-3-O-sulfate in urine were 5.481 ± 4.359 and 3.440 ± 4.160 nmol L^-1, respectively. We developed and validated a method to measure saccharin and trans-resveratrol metabolites in urine to objectively corroborate the consumption of SQ-LNS for the first time in nutrition intervention studies.

A Pharmacokinetic Study Examining Acetazolamide as a Novel Adherence Marker for Clinical Trials

RATIONALE

Accurate assessment of medication adherence is critical for determination of medication efficacy in clinical trials, but most current methods have significant limitations. This study tests a subtherapeutic (microdose) of acetazolamide as a medication ingestion marker because acetazolamide is rapidly absorbed and excreted without metabolism in urine and can be noninvasively sampled.

METHODS

In a double-blind, placebo-controlled, residential study, 10 volunteers received 15 mg oral acetazolamide for 4 consecutive days. Acetazolamide pharmacokinetics were assessed on day 3, and its pharmacokinetic and pharmacodynamic interactions with a model medication (30 mg oxycodone) were examined on day 4. The rate of acetazolamide elimination into urine was followed for several days after dosing cessation.

RESULTS

Erythrocyte sequestration (half-life = 50.2 ± 18.5 h, mean ± SD, n = 6), resulted in the acetazolamide microdose exhibiting a substantially longer plasma half-life (24.5 ± 5.6 hours, n = 10) than previously reported for therapeutic doses (3-6 hours). After cessation of dosing, the rate of urinary elimination decreased significantly (F3,23 = 247: P < 0.05, n = 6) in a predictable manner with low intersubject variability and a half-life of 16.1 ± 3.8 h (n = 10). For each of 4 consecutive mornings after dosing cessation, the rates of urinary acetazolamide elimination remained quantifiable.There was no overall effect of acetazolamide on the pharmacodynamics, Cmax, Tmax, or elimination half-life of the model medication tested. Acetazolamide may have modestly increased overall oxycodone exposure (20%, P < 0.05) compared with one of the 2 days when oxycodone was given alone, but there were no observed effects of acetazolamide on oxycodone pharmacodynamic responses.

CONCLUSIONS

Coformulation of a once-daily trial medication with an acetazolamide microdose may allow estimation of the last time of medication consumption for up to 96 hours postdose. Inclusion of acetazolamide may therefore provide an inexpensive new method to improve estimates of medication adherence in clinical trials.