True-topical pediatrics infants outer layer of skin is not fully developed, skin more fully hydrated (water soluble drugs), plastic diapers increase hydration, inflammation diaper rash increases absorption geriatric dermal thickness decreases with aging more absorption but drying, wrinkling, decreased hair follicles, decreased cardiac output, decreased tissue perfusion - decrease absorptionoral tablets and capsules are often too large for them to swallow, what does it taste like?, do they have to chew it? children with loose teeth , older adults have reduced saliva more difficult to swallowgiph some drugs are destroyed by gastric acidity reduced acidity allows these medications to be more readily absorbed and have higher concentrations in the blood stream; in contrast drugs that depend on acidity for absorption will be more poorly absorbed and have lower concentrationsgeriatric gi motility and intestinal blood flow decreased altered absorption may allow drug to stay in contact longer which would increase absorption and increase potential for toxicity, diarrhea? constipation?intestinal transit of infants increases, some meds are poorly absorbed because they move through so quicklyalso infants have an absence of enzymes needed for hydrolysis of some drugs, unable to metabolize them