Characteristics of contents of lower intestine in the 65-74 years of age range could impact the performance of safe and efficacious modified release products.

Abstract We characterized the contents of distal ileum and proximal colon of older people from a pharmaceutical product performance perspective, under two extreme situations, i.e. 5h after a glass of water to fasted volunteers (fasted state) and 5h after a high-calorie, high-fat meal to fasted volunteers (fed state). Five males and three females (65-70y) participated in a two-phase crossover study. Contents were collected via colonoscopy. In distal ileum, luminal pH was lower and buffer capacity was higher than in young adults; differences reached significance for pH in the fed state. In proximal colon, differences reached significance for pH/fasted state and for buffer capacity/both fasted and fed states. Aqueous fraction of contents contained more short chain fatty acids than previously observed in young adults. In distal ileum, osmolality was significantly higher than in young adults. In proximal colon, aqueous fraction in the fasted state was significantly lower and long chain fatty acids 5h after meal was significantly higher than in young adults. Characteristics of contents of lower intestine that are relevant to the performance of certain modified release products differ between individuals 65-74 years old and young adults, the typical age group employed in safety and efficacy studies of oral drug products.