ABSTRACT
Objective: To study on the physical and chemical properties of dichroa alkali hydrochloride and to establish a method for the determination of entrapment efficiency of dichroa alkali hydrochloride liposomes. Method: HPLC was used to determine the content of dichroa alkali hydrochloride with mobile phase of acetonitrile-water-triethylamine-glacial acetic acid(9:91:0.35:0.75) and detection wavelength at 265 nm.The oil-water partition coefficient of this compound in different pH range was measured by shake flask method.The stability of the dichroa alkali hydrochloride in phosphate buffer solution with different pH after sterilization at 125℃ for 30 min was investigated.Ammonium sulfate gradient method was used to prepare dichroa alkali hydrochloride liposomes.The microcolumn was prepared by dextran gel and cation exchange resin,respectively.Then the free drug and liposome were separated by centrifugation,the drug content was measured,and the encapsulation efficiency was calculated.The t-test was performed using SPSS 20.0 software,the differences between these two methods were compared. Result: In the pH 6-9,the oil-water partition coefficient of dichroa alkali hydrochloride increased with increasing of pH,which was between 0.016 and 1.44;the recovery rate of dichroa alkali hydrochloride after sterilization was 37.16%-57.91%.Between the dextran gel microcolumn centrifugation and the cation exchange resin microcolumn centrifugation,there was no significant difference in the entrapment efficiency of the liposomes. Conclusion: Dichroa alkali hydrochloride is suitable for preparation of liposomes.However,its stability is not ideal,so the experimental temperature should be strictly controlled in the preparation process.Dextran gel microcolumn centrifugation and cation exchange resin microcolumn centrifugation can be used to determine the entrapment efficiency of dichroa alkali hydrochloride liposomes,and the cation exchange resin microcolumn centrifugation is suggested after comparison.
ABSTRACT
AIM:To establish a method for determing the entrapment efficiency(EE) of Nobiliside-A liposome. METHODS: Sephadex G-50 column filtration method and microcolumn centrifugation method were employed to separate the free drug and liposome. In order to select a better method to determine the entrapment efficiency of Nobiliside-A liposome. RESULTS: The two methods to determine the entrapment efficiency of the Nobiliside-A liposome got the similar results. CONCLUSION: In order to determine the entrapment efficiency of Nobiliside-A liposome conveniently and rapidly, we finally select microcolumn centrifugation method.