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
BACKGROUND@#Afatinib, a second-generation irreversible epidermal growth factor inhibitor receptor for the development of non-small cell lung cancer and secondary drug resistance, has low bioavailability and adverse reactions due to current oral administration. The aim of this study was to prepare a novel drug delivery system, afatinib liposome, and to establish a method for the determination of encapsulation efficiency.@*METHODS@#Four different preparation methods were used to prepare afatinib liposomes, and the optimal preparation process was determined by comparing the encapsulation efficiency and particle size.@*RESULTS@#It has been verified that sephadex microcolumn centrifugation can be used to purify afatinib liposomes, and UV spectrophotometry can be employed to determine the entrapment efficiency of liposomes. Among different preparation methods, the encapsulation efficiency of afatinib liposomes prepared by ammonium sulfate gradient method was 90.73% and the average particle size was 108.6 nm.@*CONCLUSIONS@#Ammonium sulfate gradient method can be successfully applied to prepare afatinib liposomes that performed higher encapsulation efficiency and smaller particle size. The UV spectrophotometry employed to determine the liposome encapsulation efficiency was easy operation and with high accuracy.
Subject(s)
Afatinib , Capsules , Carcinoma, Non-Small-Cell Lung , Drug Therapy , Drug Compounding , Methods , Liposomes , Lung Neoplasms , Drug Therapy , Quinazolines , Chemistry , Therapeutic UsesABSTRACT
RESULTS: All EEs of the three VLIs were over 93%. The mean diameters, Zeta potentials and entrapment efficiencies of the three VLIs were similar. Meanwhile the three VLIs were stable in the long-term stability test. The cryo-TEM showed that almost all vesicles had spherical structure and uniform nanosize. Furthermore, some colloid substances and acicular crystal were found inside VLI-2 and VLI-3, respectively. The release rate of VLI-3 was slower, which indicated that the drug crystal probably influence the in vitro drug release. The pharmacodynamic test showed that the antitumor effect of VLI-3 was better than VLI-2 and VLI-1, while those of the latter two were superior to VI.
ABSTRACT
Objective:To prepare bererine hydrochloride ( BER) liposomes and establish an effective method for the determination of content and entrapment efficiency. Methods:BER liposomes were prepared by ammonium sulfate gradient method. The encapsula-tion efficiency of BER liposomes was respectively determined by supercentrifugation method, microcolumn gel method and ultrafiltration method, and the content of every component in BER liposomes was detected by HPLC-ELSD. Results:The results showed that super-centrifugation method could precisely separate the free drug from the liposomes. The optimum parameters of supercentrifugation method were the centrifugal speed of 60 000 r·min-1 , the centrifugal time of 1 h, the centrifugal temperature of 10℃ and the lipid concentra-tion of 6 mg·ml-1 . Conclusion:The method is simple and sensitive with good separation efficiency. HPLC-ELSD can be used to de-termine the content of every component in BER liposomes.