A quantification of gastric and duodenal fluid volumes in older adults using MRI

Older adults are an inherently heterogeneous population with various underlying pathologies, medication use, and habits. In this study, the variability of this population was studied for the gastric and duodenal fluid volumes, as the amount of gastrointestinal volumes could play an essential role in the dissolution of drugs. The fluid volumes were retrospectively quantified by using magnetic resonance imaging (MRI). In 265 included fasted older individuals, the gastric fluid volume was 28.9 ± 21.1 mL (arithmetic mean ± standard deviation). No significant covariate-effect on stomach fluid volume was observed for various medication use, pathologies, and habits (e.g. hypertension, smoking, proton-pump inhibitors (PPIs), and aspirin). The gastric fluid volume remained constant with increasing age and had a high variability. The volumes and the variability were, however, not higher than the gastric values reported in healthy younger adults. The duodenal fluid volume was 16.6 ± 10.0 mL and a slight but statistically significant decrease with age was seen. In addition, cystic pancreas, obesity, diuretics, and PPI use demonstrated a moderate but significant correlation with the duodenal fluid volume. The findings of this study could be considered when developing and testing new drug candidates for the older adult population. For example, the volumes including their variability could be used as an input in physiologically based pharmacokinetic (PBPK) modelling approaches to predict drug exposure in this population.