FIG. 1.

Elution from PMMA beads containing 2.0 g daptomycin as a function of xylitol. Assays were done with PMMA beads containing 2 g of daptomycin and 0 (⧫), 7 (•), 14 (▴), or 28 (▪) g of xylitol per 40-g packet of PMMA. The amount of daptomycin present in the eluate was determined by bioassay. Results are reported as the averages ± the standard deviations from three experiments. Missing data points in the series without xylitol (⧫) are indicative of daptomycin levels below the level of detection. Results obtained by HPLC with the formulation containing 28 g of xylitol are shown for comparison (⋄). The upper dashed line indicates the 100× threshold (100 μg/ml), while the lower dashed line indicates the 5× threshold (5 μg/ml). Statistical analysis confirmed a significant difference (P ≤ 0.05) between PMMA with (•) and without (⧫) 7 g of xylitol and between PMMA formulations containing increasing amounts of xylitol (•, ▴, and ▪).