Studies on systemic absorption of tobramycin in polyethylene glycol ointment applied to wounds of burn patients.

The penetration of tobramycin ointment (0.2 per cent) through human burn wounds was studied in two patients with superficial dermal burn (SDB) and deep dermal burn (DDB), two patients with DDB, one patient with full thickness burn (FB) and one patient with burn ulcer (BU). After application of the ointment, the absorption of tobramycin occurred promptly with a peak level at 2-6 h in the sera of patients with SDB + DDB and DDB only. In the BU patient it was found at 2 h; while in the FB, at 10-12 h. The excretion of tobramycin into the urine was also studied. The absorption rate constants (ka) of the two SDB + DDB patients were 0.31 and 0.74, of the two DDB patients, 0.079 and 0.18, and those of the DB and the BU patients, 0.053 and 0.95, respectively. The absorption ratios of tobramycin (amount excreted into the urine during 24 h/applied dose) were different, depending on the condition of the burn wound, and ranged from a low of 10.3 per cent (FB) to a high of 44.0 per cent (BU). These results show that the treatment of burn patients with tobramycin ointment to control burn wound infection should be carefully supervised, especially in the case of BU.