(322a) A Study of Diffusion and Release in Porous Alumina

A model is presented for the diffusion and release of Doxorubicin (Dox) and Sulforhodamine 101 (SR101) in porous alumina. The diffusion of Dox and SR101 were studied using fluorescence recovery after photobleaching (FRAP) at pH's 5.0 and 7.4 over the temperature range 273K to 298K. Data from these experiments were fitted to first-order kinetics to predict the effects of pH and temperature on the adsorption of Dox and SR101. It was observed that the diffusion of Dox is dependent upon the pH whereas the release is not. It was further found that the diffusion of SR101 is independent of pH and that the release is temperature dependent. These observations suggest that the pH induced charge interactions between the diffusing species and the alumina surface play a significant role in the uptake and release from porous alumina.