This study evaluated the pharmacokinetics of commercial gentamicin-impregnated collagen sponges (GICS) applied subcutaneously in dogs. In six healthy beagles, an 11 ×6cm subcutaneous pocket was created, a folded 10×10cm GICS was inserted, and saline was injected to mimic a seroma. Wound fluid samples were aspirated, and the gentamicin concentration was determined. Simultaneously, blood samples were collected to evaluate the corresponding systemic gentamicin concentration. All samples were collected before and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 18, 24, 36, 48, 72, 96, 120, and 168hours after GICS placement.The local Cmax of gentamicin was reached after 0.5hours (range, 0.5-1.0hours) post-implantation in 5/6 dogs at a median concentration of 2053.3µg/mL (range, 918.0-2791.9µg/mL). Whitin 24hours, the local concentration dropped below the MIC for Staphylococcus sp. (4µg/mL) in 5/6 dogs. Plasma Cmax was achieved at a median of 1.2hours post-implantation (range, 1.0-2.0hours) and reached a median concentration of 10.3µg/mL (range, 8.8-18.03µg/mL). After 6hours, the gentamicin concentration in the plasma was below 4µg/mL in all dogs.The GICS provided a high local concentration of gentamicin in a short time with a local Cmax:MIC ratio of 513:1, largely sufficient to eliminate susceptible bacteria, including methicillin-resistant Staphylococcus pseudintermedius (MRSP) and Pseudomonas sp., in a clinical setting. The repeated administration of saline in the present study seemed to have induced a quicker gentamicin release from the GICS than described in previous studies that typically dealt with "drier" wounds.