AntacidsMagnesium HydroxideAluminum HydroxideAbsorptionIntestinal AbsorptionSimethiconeMagnesium OxideCalcium CarbonateSilicic AcidBiological AvailabilityHeartburnDrug CombinationsHistamine H2 AntagonistsRanitidineSodium BicarbonateCimetidineDrug InteractionsSiliconesFood-Drug InteractionsEsophagitis, PepticAdministration, OralGastric Acidity DeterminationDuodenoscopyTechnetium Tc 99m PyrophosphateSkin AbsorptionDosage FormsCross-Over StudiesFamotidineAnti-Ulcer AgentsSucralfateHydrogen-Ion ConcentrationCarbonatesAlginatesDimethylpolysiloxanesGastric AcidEnoxacinAluminumGastroesophageal RefluxSpectrophotometry, AtomicX-Ray Absorption SpectroscopyJejunumPneumonia, Aspiration