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Figure 1. Antibiotic release and matrix degradation of calcium polyphosphate disks in 0.1 M Tris-buffered saline solution over 7 days from non-gelled disks (•), 24-hour-gelled disks (
), and five-hour-gelled disks (
). Cefuroxime release shown as a percent of the total antibiotic incorporated into the calcium polyphosphate disks (A), and the rate of cefuroxime release (mg/hr) at 13 time-points over the 7 days (B). Calcium release as a percent of the total available in the calcium polyphosphate matrix (C), and the rate of calcium release (mg/hr) at individual time-points (D), along with phosphate release as a percent of the total available in the calcium polyphosphate matrix (E), and the rate of phosphate release (mg/hr) at individual time-points (F) describe the matrix degradation of the calcium polyphosphate disks. Change in pH over time from the collected 7-mL samples was tracked (G). Cumulative release of cefuroxime (mg) is shown for the first 4 days (H) of the elution study, to highlight the linear portion of the 24- and five-hour-gelled curves. All samples for each time-point are presented as mean ± standard error (n = 14); blank samples (n = 2) did not significantly differ from their gelled and non-gelled equivalents and, thus, were not included in graphs C through G.
