Estimation of drug absorption in antibiotic soaked bone grafts.

INTRODUCTION: There is paucity of literature about antibiotic uptake in bone grafts soaked in antibiotic solutions at room temperature in the operation theatre. We hypothesized that if bone grafts are dipped in different strengths of antibiotic solutions for sufficient period, their utilization at the target site helps in localized release of antibiotics in adequate inhibitory concentration to achieve the bacterial regression. The purpose of the study was to find out: (1) Optimum duration, strength, and volume of antibiotic solution required for dipping bone grafts at room temperature prior to the use. (2) What could be the clinical implications of the results obtained?

MATERIALS AND METHODS: Bone shavings from total knee replacements were processed, frozen and transported to bio-analytical laboratory. The bone fragments were then impregnated with different volume and different strength of gentamicin and vancomycin over different time periods. The soaked bone samples underwent further processing for analysis on liquid chromatography tandem mass spectrometry (LC-MS/MS) system.

RESULTS: After series of bio-analytical estimation for the soaked drug concentration among bone fragments; the optimal estimation was found with 0.2 mL of 2% strength of gentamicin and vancomycin, the optimal time was found with soakage up to 30 min. These estimated values of soaked antibiotics were five 5 times higher than required minimal inhibitory concentration (MIC) values for bacterial regression.

CONCLUSION: Use of antibiotic soaked bone allografts at target sites as potential drug carrier can be a hassle- free yet cost- effective and safe process for achieving maximum bacterial regression.