Figure 2.

Microsphere characterization and interleukin-1 receptor antagonist (IL-1ra) release kinetics. (a) Microsphere morphology upon fabrication as viewed under scanning electron microscopy. (b) Cumulative release of IL-1ra from microspheres suspended in phosphate-buffered saline under gentle agitation over 35 days. Each data point is the mean ± standard deviation of three separate aliquots of microspheres in suspension. The dashed line represents a power series curve fit to the raw data. The power series curve is defined in the 'Microsphere morphology and IL-1ra release kinetics' section of the text.