8. PEDIATRIC PHARMACOKINETICS Adult pattern Adult pattern Colonization phase MICROBIAL FLORA Developed Developed by 1 yr Decreased PANCREATIC ENZYME ACTIVITY Developed Developed Underdeveloped BILIARY FUNCTION Normal Normal Reduced ABSORBING GUT SURFACE Increased Increased Decreased, irregular INTESTINAL MOTILITY Decreased Decreased at 6-8 mth Increased Increased (delayed) GASTRIC EMPTYING Adult values Adult values at 3 mth Neutral at birth up to 1 hrs GASTRIC CHILDREN INFANTS NEWBORNS PHYSIOLOGIC VARIABLES FACTORS AFFECTING ABSORPTION IN CHILDREN