Supercritical Carbon Dioxide Impregnation of Vitamin D_3 into Chitosan Particles

The impregnation of vitamin D3 into chitosan particles using supercritical CO2 fluid was investigated with respect to the effects of pressure,temperature and length of impregnation time evaluated by UV-vis spectroscopy.The results showed that with increasing pressure,VD3 impregnation amount initially increased and then decreased;as temperature increased,an identical change pattern in VD3 impregnation amount was observed.VD3 impregnation amount reached its maximum value under the conditions of 20 MPa and 35 ℃.Increasing length of impregnation time from 1 to 3 h resulted in a higher VD3 impregnation amount when pressure and temperature kept unchangeable.