What is the shelf life of calcium phosphate antibiotic beads?

• A. 60 days
• B. 90 days
• C. 120 days
• D. 180 days

Answer: (C)

Shelf life is the period during which antibiotic-loaded calcium phosphate beads stay potent and usable when stored per the manufacturer's guidelines. For these beads, the stability window is typically about four months, or roughly 120 days, assuming proper storage (cool, dry conditions). This timeframe reflects both the antibiotic’s stability within the bead matrix and the bead’s structural integrity. Shorter durations like 60 or 90 days would limit the usable period before implantation or use, while a longer period such as 180 days often exceeds typical stability expectations and isn’t recommended. So, 120 days is the standard shelf life.