Study On Freeze-drying Process Of Ginseng And Cilastatin

Freeze-drying technology has been widely used in the fields of biological products,medicine,and food.But because the freeze-drying depend on the low vacuum and temperature conditions,the drying will have high drying costs,low production and high energy consumption.This thesis,based on the analysis of freeze-drying mechanism,studies application of the freeze-drying technology in traditional Chinese herbal medicine(Ginseng as an example)and synthetic drugs(Cilastatin as an example),and discusses the influence of process parameters on drying.The eutectic point of ginseng is measured by differential scanning calorimetry(DSC)and resistance measurement,and the temperature obtained by these two methods are basically the same-15 ℃.The thermal conductivity of ginseng was decreased according to the method of unsteady cable probe.Ginseng density is measured before and after drying and gets the initial water content of ginseng.Firstly fixing ginseng parameter of slices thickness,carrying out multiple sets of freeze-drying tests of drying chamber pressure,according to three-test indicators of quality drying rate,production capacity and area contraction ratio,and integrated evaluation of the series of freeze-drying,the best drying chamber pressure is identified.Under the condition of the best drying chamber pressure,carrying out multiple sets of freeze-drying tests of loading height,according to three test indicators of quality drying rate,production capacity and area contraction ratio,and integrated evaluation of the series of freeze-drying,the best loading height is confirmed;which gets the optimized ginseng freeze-drying parameters as follows:slice thickness 7 mm,the heating plate temperature 60 ℃,drying chamber pressure 50 Pa,and under these conditions,the drying rate is 1.52 h-1,production capacity of 101.2 g/(h · m2),area contraction rate 20%,water content of freeze-dried ginseng 6%,which can meet the market requirements of less than 8%.The external standard method was used to determine the concentration of Cilastatin solution,and the eutectic point temperature of Cilastatin-12 ℃ was obtained by the method of resistance measurement.Based on the stability data of Cilastatin,the temperature of freeze-drying heating plate is determined;And fixing the parameter of loading height,carrying out multiple sets of freeze-drying tests of drying chamber pressure,according to three test indicators of water content,appearance after drying and production capacity,and integrated evaluation of the series of freeze-drying,the best drying chamber pressure is identified.Under the condition of the best drying chamber pressure,carrying out multiple sets of freeze-drying tests of loading height,according to three test indicators of water content,appearance after drying and production capacity,and integrated evaluation of the series of freeze-drying,the best loading height is confirmed;Which gets the optimized parameter of Cilastatin freeze-drying as follows:loading height 12 mm,heating plate temperature 45 ℃,drying chamber pressure 40 Pa,and under these conditions,the production capacity is 29.3 g/(h · m2),and water content of freeze-dryied Cilastatin is 1.4%,which can meet the quality requirement of less than 2%specified in the pharmacopoeia.