GENTAMICIN CONCENTRATIONS IN HUMAN SUBCUTANEOUS TISSUE

Wound infections frequently originate from the subcutaneous tissue, Th e effect of gentamicin in subcutaneous tissue has, however, normally b een evaluated from concentrations in blood or wound fluid, The aim of the present study was to investigate the pharmacokinetic properties of gentamicin in human subcutaneous adipose tissue by a microdialysis te chnique, Seven healthy young volunteers each had four microdialysis pr obes placed in the fat (subcutaneous) layer of the abdominal skin, Aft er the administration of a 240-mg gentamicin intravenous bolus, consec utive measurements of the drug concentrations in serum and subcutaneou s interstitial fluid were obtained simultaneously for 6 h, The tissue gentamicin concentration peaked after 10 to 30 min, The peak concentra tion in the tissue was 6.7 +/- 2.0 mg . liter(-1) (standard deviation) , equivalent to 39.1% of the peak concentration in serum, The area und er the concentration-versus-time curve for the first 6 h in the tissue was 1,281.7 +/- 390.0) mg . min liter(-1), equivalent to 59.7% of the area under the concentration-versus-time curve in serum, It is conclu ded that the microdialysis technique can be used to make dynamic and q uantitative measurements of the gentamicin concentration in human subc utaneous tissue, In this adipose tissue, the peak concentrations of ge ntamicin were approximately seven times the MIC for Pseudomonas aerugi nosa and 33 times the MIC for Staphylococcus aureus after the administ ration of an intravenous bolus of 240 mg, indicating the presence of s ufficient concentrations in the adipose tissue to be effective against common bacteria.