Comparative penetration of ceftazidime into cardiac and skeletal muscle in rabbits

The concentrations of ceftazidime attained in cardiac and leg muscles of rabbits were compared after a single intramuscular injection of 100 mg/kg. Simultaneous measurements of muscle and muscle fluid over an 8-hour period showed that ceftazidime penetrated heart muscle more rapidly and to a greater extent than leg muscle. Although the half-lives did not vary, the areas under the time/concentration curves for heart muscle and heart muscle fluid were significantly greater than those for leg muscle and leg muscle fluid. It is suggested that an increased fluid content and vascularity of cardiac muscle may explain these results. This study also confirms previous reports that whole muscle tissue levels of beta-lactam antibiotics substantially underestimate the actual concentrations present in the extracellular fluid.