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September 28, 2017

Project Spotlight: CHARM – Antibiotic Impregnated PMMA Cranial Implants and the Fight against Multi-Drug Resistant Organisms

In support of the Naval Medical Research Unit – San Antonio’s Carniofacial Health and Restorative Medicine (CHARM) directorate, CAMRIS is involved in a study related to cranioplasty infection, multi-drug resistant organisms, and nanomaterials. Given the high infection rate associated with cranioplasty, the CAMRIS team is working on a project incorporating antibiotic powder into polymethylmethacrylate (PMMA) cranial implants for localized prophylactic drug delivery.

The team first worked to decipher antibiotics that can withstand the high temperatures needed during the curing process and polymerization reaction of PMMA. After identification of a group of antibiotics that retain activity despite exposure to these conditions, the team shifted focus onto the inclusion of the antibiotics into PMMA. By solubilizing the drugs into liquid form and combining it with what became PMMA, the new PMMA is molded into identical rod shapes, each rod containing a separate antibiotic. These rods are then initially tested for flexural strength, elution capabilities, and other properties over a 30-day period. The study objective is to determine which antibiotics are most effective without negatively impacting PMMA.

Since many infections witnessed in the military theater are multi-drug resistant, the team on this project also work to create a cocktail of antibiotics to thwart multi-drug resistant organisms. Once the cocktails are developed, they will be added to PMMA and evaluated. Of note is the planned testing and analysis of the cocktail against a select group of clinically relevant strains secured from the Infectious Disease Clinic at nearby Brooke Army Medical Center.

CAMRIS staff duties on this project include: protocols and execution of the temperature stability studies; elution studies; antibiotic activity studies (after elution); and antibiotic cocktail design studies. Additionally, CAMRIS also is responsible for the following: developing a protocol to incorporate the antibiotics into the PMMA; executing the incorporation and fabrication of the rods; setting up the HPLC UV/Vis or LC/MS analysis to be done offsite at the University of Texas Health Science Center; and overseeing that data collection and analysis was done correctly. The first author of the project is a CAMRIS employee.