Purpose: Imipenem-Cilastatin is an antibiotic traditionally used to treat gram-negative bacterial infections. Recently, this agent has been suggested as a temporary embolic agent in musculoskeletal conditions where there is joint hypervascularization, such as knee osteoarthritis. However, little is known about the characteristics of Imipenem-Cilastatin or its mechanism of action as a temporary embolic agent. This study aims to determine the characteristics of Imipenem-Cilastatin in vitro, to better understand how this agent could be most effectively applied for embolization in clinical practice.
Materials and Methods: The size distributions and degradation rates of the particles as a function of time, temperature, concentration and suspension media were measured. Light microscopy assessed morphological changes, a Coulter counter measured particle size distributions, and ultraviolet-visible spectroscopy (UV-Vis) assessed the rate of Imipenem breakdown over time. In vitro flow phantoms were created to assess agent accumulation and degradation under flow.
Results: Imipenem-Cilastatin in saline changed from a white cloudy solution to a transparent orange solution over a period of days, consistent with the expected degradation product of Imipenem. Coulter counter data and microscopy showed that initial particles were crystalline and polydisperse, from 1μm to 50μm in size, and degraded over time, with an increase in particles < 10μm. UV-Vis and in vitro fow experiments are in progress and will contribute toward developing a model of embolic mechanism and degradation as a function of flow rate, physical and chemical properties.
Conclusion: The degradation of Imipenem-Cilastatin were effectively measured in vitro, towards elucidating its future application as a temporary embolic agent for joint hypervascularization.