A diffusion chamber technique for measuring concentrations of antibiotics in interstitial fluid

A method for collecting soft tissue interstitial fluid in experimental animals for the measurement of antibiotic concentrations is described. Diffusion chambers with permeable membranes of 0.45 micron porosity were implanted subcutaneously for four days in order to determine simultaneous concentrations of ampicillin and clindamycin in serum and chamber fluid after perioral administration in rabbits and of oxytetracycline after intravenous injection in dogs. The results are discussed in view of findings from other investigators using different types of tissue cages.