Erythromycin-antacid interaction.

The in vitro release of erythromycin stearate in the presence of aluminium hydroxide, aluminium trisilicate, magnesium oxide, magnesium trisilicate, sodium hydrogen carbonate and a combination of aluminium hydroxide gel, magnesium hydroxide and dimethyl polysiloxane has been studied by the USP XX dissolution method. The dissolution of erythromycin was found to be markedly retarded in the presence of all the antacids studied except sodium hydrogen carbonate. An attempt was made to elucidate the mechanism of this effect.