Fig. 3.

Release profiles of u-chitosan and m-chitosan microspheres. The microspheres (10 mg) were suspended in 1 ml of PBS at pH 7.4 (120 mM NaCl, 2.7 mM KCl, 10 mM PBS) at 37 °C under stirring. At predetermined time intervals, the suspension was centrifuged and replaced with the same volume of fresh medium. The DNA concentration in the supernatant was determined in triplicate by UV absorbance at 260 nm. All data were expressed as mean ± SD (n = 3) (p < 0.001).