Lack of effect of amoxycillin on the absorption of ofloxacin.

Amoxycillin and ofloxacin are both well absorbed after oral administration, despite being hydrophilic. We have studied the possibility of competition between these two drugs for a carrier-mediated transport system, since both drugs are absorbed by saturable processes in the rat small intestine. Oral doses of amoxycillin (3 g) and ofloxacin (400 mg) were given separately and in combination to six healthy volunteers. Blood samples were taken over 30 h and plasma concentrations of the respective drugs were measured by HPLC. Amoxycillin did not alter the pharmacokinetics of ofloxacin.