Hydrogelexpander als Medikamentenabgabe-System für Antibiotika

Abstract

The suitability of a high-hydrophilic osmotic self-inflating hydrogel expander consisting of a co-polymer of N-vinylpyrolidone and methyl methacrylate as a drug delivery system for antibiotics to prevent a postoperative infection was investigated in a laboratory setting. The dry expanders were incubated in a 0.3% solution of Ofloxacin or Tobramycin for 24hours. The completely swollen expander had increased in volume from 0.3mL to almost 3mL(adsorbing 2.7 mL of the 0.3% solution, i.e.,8.1mg of Ofloxacin or Tobramycin, respectively). Addressing the elimination of both antibiotics, the concentrations in 15mL elution medium (simulating the volume of the orbit in a newborn baby) were measured after 0.25, 1, 2, 6, 24, 48 and 72 hours of elution. 0.9% sodium chloride (B. Braun Melsungen, Germany) was used as elution medium. To imitate fluid exchange due to blood perfusion in the surrounding tissue the medium was renewed after every sampling. For each substance 10 expanders were tested. Concentrations of antibiotic were determined by HPLC/UV for Ofloxacin and by using a specific fluorescence-polarisation immunoassay (Abbott TDx) for Tobramycin. Mean concentrations of Ofloxacin at 0.25, 1, 2, 6, 24, 48 and 72 hours after beginning of the elution were 50.2, 46.8, 41.2, 75.4, 88.2, 46.2 and 19.1µg/mL, respectively. The cumulative amount of Ofloxacin eluted after 72 hours reached 68% of the loading dose. The corresponding mean concentrations of Tobramycin were 38.8, 48.5, 40.5, 69.8, 88.7, 119.3 and 71.6µg/mL. The cumulative eluted amount was 88%. The investigated hydrogel expanders soaked in 0.3% antibiotic solution can store and later on release sufficient amounts of Ofloxacin or Tobramycin to produce antimicrobial effective concentrations in vitro in the surrounding environment. This principle, when used in a clinical setting, might help to eliminate post-implantation infection which is one of the major complications in clinical use.