Background: ^99mTc-labeled antibiotics have an important role in the development of new radiopharmaceuticals for infection imaging. ^99mTc-kanamycin was one of radiolabeled antibiotics that used for diagnostic of bacterial deep site infection. The biodistribution or pharmacokinetics of ^99mTc-kanamycin may be altered by a variety of drugs, disease states, and surgical procedures which can have a significant clinical impact on safety, scan interpretation, and diagnostic imaging accuracy.

Objective: This study was conducted to identify an interaction between several antibiotics with ^99mTc-kanamycin based on the pharmacokinetic parameters.

Material and Methods: In vivo studies were conducted on twenty-four male Balb/C mice (28 days old) and divided into eight groups (n=3). At first, each group of mice were treated with kanamycin, ciprofloxacin, amoxicillin, levofloxacin, cefotaxime, chloramphenicol, and cefixime. Two hours post oral of antibiotics treatment, each mice were given a single intravenous injection of 25µci/mL ^99mTc-kanamycin. Blood were collected from the coccygeal vein in interval at time within 5 minutes to 24 hours. Then the radioactivity in the blood sample was measured using Automatic Gamma Counter with NaI (Tl) detector.

Results: The results of the pharmacokinetic parameters showed that administration of kanamycin, ciprofloxacin, and amoxicillin on blood clearance of ^99mTc-kanamycin had no significantly different indicated by one way ANOVA analysis (p>0.05). The administration of levofloxacin caused pharmacokinetic interactions significantly different (p<0.05) with t_1/2β 20.11 ± 0.92 h and increased C_max 10.86 ± 3.05 and AUC_0-inf 20.04 ± 5.27. Administration of cefotaxime increased the C_max and AUC_0-inf values, which are respectively 11.47±1.98, and 23.90 ± 2.85. Changes in pharmacokinetic parameters also for administration of chloramphenicol with C_max 12.29±0.36 and t_1/2β are longer, which is 21.43±5.05 h, while administration of cefixime before ^99mTc-kanamycin prolonged t_1/2β 21.50±3.68 h, C_max 10.80±0.89 and AUC_0-inf 112.20±10.79.

Conclusion: Pharmacokinetics studies showed that treatment of antibiotics before administration of ^99mTc-kanamycin influences the pharmacokinetics profile of ^99mTc-kanamycin. The absorption rate and t_1/2β of ^99mTc-kanamycin was prolonged for levofloxacin, cefotaxime, chloramphenicol, and cefixime. While administration of antibiotics such as kanamycin, ciprofloxcin, and amoxicillin did not change the pharmacokinetic parameter.