Equilibrium Moisture Sorption Isotherms of Aspirin

Equilibrium Moisture sorption isotherms are very important in drying and storage analysis. Experimental moisture equilibrium data (adsorption desorption) of Aspirin were determined using the static method saturated salt solutions that by exposing material to different conditions temperatures water activities. Three (25, 30, 40Cº) activities range (6.3- 83.6%) used. The results showed content increased with increase activity at any temperature decreased constant activity. increases increasing when was kept constant. isotherm curves type II according Brunauer`s classification. hysteresis effect not distinctly expressed only for values 25ºC. experimental fitted two models (GAB Henderson).The average relative deviation between calculated obtained select best model. GAB Henderson models, obtaining 3.54 1.42 % coefficient regression 0.98 0.977 respectively. model found be fit out predict behavior Aspirin.