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Show 62 Jason DeGooyer college of pharmacy Although incorporating antibiotics into biomedical devices to reduce post-operative infections is not a new concept, local antibiotic delivery to poorly vascularized tissues such as bone remains a pharma-ceutical engineering challenge. Previous attempts to reduce bone infections have used bone grafts and other synthetic bone void fillers to deliver an antibiotic locally. Unfortunately, their pharmacokinetics are inadequate to fully address the scope of the problem. Alternatively, antibiotics have been incorporated into bone cements, commonly used in revision arthroplasty. Although antibiotic-loaded bone cement is able to extend the release of antibiotic up to 2 weeks, its exothermic polymerization limits the scope of antibiotics suitable for inclusion. Additionally, the glassy rigidity of the material also precludes full release of antibiotic, often falling below the minimal inhibitory concentration necessary to eradicate opportunistic bacteria. Development of a polycaprolactone (PCL) polymer-controlled local antibiotic release from an osteoconductive allograft bone void filler delivery vehicle provides the opportunity to engineer a designer local antibiotic delivery system with tailored kinetics over 6-8 weeks to support bone healing and prevent infection. Determination of the amount of drug incorporated in the polymer formulation and subse-quently applied to the bone void filler is critical for the success of the project. Thus, this research describes methodologies developed to accurately quantify the amount of tobramycin, ciprofloxacin, or vancomycin applied to the bone graft void filler. Based on differential polymer/drug solubilities, phase extraction methods were used to segregate the antibiotic and polymer components of the system. Drug load was subsequently quantified using optical absorbance or fluorescence assays. Methods were validated based on control samples without polymer or bone graft, revealing over 85% drug recovery over the antibiotic assay linear range. More precise antibiotic release kinetics can now be determined by normalizing the antibiotic released by the amount of antibiotic applied, now accurately determined. Ultimately, this infor-mation can be used to determine the mass balance after drug release so as not to incur some of the pitfalls of current antibiotic-releasing implants. DRUG RELEASE FROM A POLYMER-CON-TROLLED LOCAL ANTIBIOTIC DELIVERY SYSTEM USING AN OSTEOCONDUCTIVE BONE GRAFT VOID FILLER Jason DeGooyer (David Grainger, Amanda Brooks) Department of Bioengineering Department of Pharmaceutics and Pharmaceutical Chemistry University of Utah UNDERGRADUATE RESEARCH ABSTRACTS David Grainger Amanda Brooks |