Preparation of propranolol hydrochloride cubosomes by pH gradient method / 药学实践杂志

Objective To prepare propranolol hydrochloride loaded cubosomes (PPL-Cubs) with high entrapment efficiency. Methods PPL-Cubs was prepared by pH gradient method. Pressure and cycles of high pressure homogenization, dosage of glyceryl monooleate and poloxamer 407 were optimized to prepare blank cubosomes with particle size and polydispersity index as the indexes. The influences of various factors, including exterior pH values, internal pH values, the ratio of carrier to drug, particle size and polydispersity index of blank cubosomes, incubation temperature and time, and drug concentration on the entrapment efficiency were investigated. Results The blank cubosomes with small particle size and polydispersity index was prepared under homogenization conditions of 900 bar for 7 cycles, glyceryl monooleate dosage of 25%, and poloxamer 407 dosage of 5%. PPL-Cubs showed high entrapment efficiency with exterior pH value of 8.5, internal pH value of 3.0, ratio of carrier to drug of 6∶1, incubation temperature of 20 ℃, and incubation time of 15 min, and drug concentration of 1%. The particle size and polydispersity index of blank cubosomes showed no influence on entrapment efficiency. Conclusion PPL-Cubs with high entrapment efficiency could be prepared under the pH gradient method.

Preparation of berberine hydrochloride liposomes by a new pH gradient method / 中国药学杂志

OBJECTIVE: To prepare berberine hydrochloride liposomes and investigate the influence of different factors on the entrapment efficiency. METHODS: Berberine hydrochloride liposomes were prepared by a novel pH gradient method. The transmembrane gradient was set up by ion exchange resin. UV-visible spectrophotometry and laser particle analyzer were applied to determine the entrapment efficiency and the size of berberine hydrochloride liposomes, respectively. The influences of various factors, including exterior pH values, the basic solutions of external water phase, phospholipids, incubation temperature and time, adding sequence and the ratio of drug to lipid, on the entrapment efficiency were investigated. RESULTS: Entrapment efficiency increaced with higher pH values, the best basic solution is phosphate buffer and HSPC is the most suitable phospholipid, the entrapment efficiency was enhanced by increacing incubation temperature and time, not affected by adding sequence, and the optimal ratio of drug to lipid was 1: 10. The entrapment efficiency of berberine hydrochloride liposomes under the optimum conditions was (98.6 ± 0.68)% (n = 3), and the mean diameter was 124.1 nm. CONCLUSION: The berberine hydrochloride liposomes with high entrapment efficiency are prepared by a novel pH gradient method, and the method is proved to be feasible. Copyright 2013 by the Chinese Pharmaceutical Association.

Preparation and in vitro evaluation of ofloxacin liposomes for increasing bacteria sensitivity / 中国药学杂志

OBJECTIVE: To prepare ofloxacin liposomes for increasing bacteria sensitivity, and lo evaluate its in vitro properly. METHODS: Ofloxacin liposomes were prepared by pH gradient method using phospholipid and cholesterol as materials. The effects of pH value and the warming temperature and time on encapsulation efficiency were investigated. The particle size of liposomes was determined and the morphology was investigated by transmission electric microscope (TEM). The in vitro release experiment was carried out vising physiological saline as the medium. The bacteriostatic action against Staphylococcus aureus was investigated using disc diffusion test and dilution test. RESULTS: The maximum encapsulation efficiency of 82.40% could be achieved when pH value was 7.0, warming temperature was 50°C and warming time was 5 min. The average particle size of the liposomes was 174nm, and the ofloxacin liposomes showed good morphology under TEM. The liposomes could release ofloxacin in a sustained manner in vitro. The ofloxacin liposomes and solution showed same inhibition zones in disc diffusion test, while their minimal inhibitory concentrations determined by dilution test were 0.39 and 0.78μg · mL-1, respectively. CONCLUSION: Ofloxacin liposomes can be prepared by pH gradient method with high encapsulation efficiency, and the bacteriostatic effect of ofloxacin against Staphylococcus aureus can be improved by incorporating it into liposomes.

Preparation of tetrandrine-doxorubicin complex liposomes and its release property in vitro / 中草药

Objective Selecting doxorubicin and tetrandrine as model drug to prepare complex liposomes, study the methods of preparation, and research its release property in vitro. Methods The formulation of tetrandrine-doxorubicin complex liposomes was optimized by three different kinds of methods. And the optimum formula was selected through the orthogonal test according to the entrapment efficiency. Results Tetrandrine-doxorubicin complex liposomes were prepared by (NH4)2SO4-gradient method combined with pH gradient method. One optimum recipe was founded that tetrandrine-doxorubicin complex liposomes/ egg phosphatidyl choline was 1∶20, egg phosphatidyl choline/cholesterol was 3∶1, pH value was 7.6, incubation temperature was 50 ℃, concentration of (NH4)2SO4 was 250 mmol/L. The doxorubicin completely released within 24 h, and the tetrandrine released within 16 h. Conclusion Tetrandrine-doxorubicin complex liposomes have high entrapment efficiency with fine-looking, which is better for the further studies

Preparation and quality control of tetrandrine-doxorubicin complex liposomes / 重庆医科大学学报

Objective:To prepare doxorubicin-tetrandrine complex liposomes for technology study and quality control.In order to provide a new idea to reverse the tumor multidrug resistance in clinic.Methods:The formulations of doxorubicin-tetrandrine complex liposomes were optimized by three different kinds of methods.And the optimum formula was selected according to the entrapment efficiency.Re- sults:The complex liposomes were prepared by(NH4)2SO4-gradient method combined with pH gradient method according to optimum recipe.The optimum recipe of DOX-TET liposome was founded as DOX-TET/EPC of 1∶10,EPC/Ch of 3∶1,pH value of 7.6,incubation temperature of 50℃,(NH4)2SO4 concentration of 250 mmol/L.Under the formulation,DOX and TET were encapsulated 90.77%and 80.12%,respectively.Conclusion:The doxorubicin-tetrandrine complex liposomes have high entrapment efficiency with fine looking, which provides basis for the further studies.