/ 100 gr dry skin) using petroleum ether as the solvent. Design of experiments of Aloe vera gel supercritical extraction was performed on the temperature, pressure, carbon dioxide flow rate and dynamic time. RSM experiments were performed at the following range of operating conditions: (1) Temperature: 40-60°C, (2) Pressure: 200-320 bar, (3) Superctitical solvent flow rate: 0.5-1.5 ml CO 2 /min, and (4) Dynamic time: 60-140 min. The optimum static time was determined to be 15 min and 0.6 mm of particle sizes were used. The quadratic response surface model was obtained via the utilization of RSM central composite design (CCD). The results of this study demonstrated that flow rate of carbon dioxide had no significant effect on neither extracted oil yield nor recovery of Alpha Tocopherol. The maximum ?-tocopherol recovery was obtained with employing RSM predicted model for the optimum extraction operating conditions of 60°C, 320 bar, 0.5 ml CO 2 /min and 140 min. Similarly, the maximum extraction yield was obtained with employing RSM predicted model for the optimum extraction operating conditions of 57.8 °C, 32 Mpa, 1.5 ml/min and 140 min. Moreover, in the present study, a mathematical modeling for extraction of Alpha Tocopherol and Beta Carotene from Aloe vera plant gel and skin using supercritical carbon dioxide was performed. The shrinking core model was applied to analyze the experimental results. This model has been successfully applied in the process such as solid-fluid reactions, adsorption, ion exchange and supercritical extraction of natural materials. The model successfully fitted the experimental data for larger particle size. Genetic algorithm was applied to determine the optimal value of temperature, pressure, supercritical solvent flow rate and dynamic time. Optimal extraction conditions for maximum extraction yield of Beta Carotene were determined : 323.15 K, 29 MPa ، 1 ml CO 2 /min and 260 min. Genetic algorithm was predicted Optimal operation conditions for supercritical fluid extraction of Beta Carotene as well as RSM. Alpha Tocopherol and Beta Carotene analyses were performed by high performance liquid chromatography (HPLC) and UV spectrophotometer, respectively. Overall, the results indicated that supercritical extraction is a reliable and promising technique for mass production of very valuable pharmaceutical antioxidant compounds such as Alpha Tocopherol and Beta Carotene. Moreover, this method is superior with respect to liquid solvent extraction due to the advantages of supercritical carbon dioxide compared to toxic liquid solvents. So supercritical fluid extraction could be an alternative technology in the pharmaceutical industry for the separation of antioxidant component from Aloe vera plant. This ?nding results in an interesting advantage in the economics of an alternative process to
