In vitro Interaction of Fexofenadine with H2 Receptor Antagonist

Fexofenadine is a second generation H1-receptor antagonist, much widely used due to its non-sedative effects. The in vitro availability of fexofenadine in the presence of H2-receptor antagonist (cimetidine, ranitidine and famotidine) was studied on a BP 2005 dissolution test apparatus to observe the kinetics and energies of fexofenadine in the presence of H2-receptor antagonist (cimetidine, ranitidine and famotidine). These studies were carried out in buffers of pH 2, 4 (simulated gastric juice), 7.4 (blood pH) and 9 (simulated intestinal juice) at 37°C and at elevated temperatures. These studies showed that all H2-receptor antagonist (cimetidine, ranitidine and famotidine) interact to fexofenadine. Moreover, these interactions were not temperature dependent but pH dependent.