Optimization of the prescription of Calcein-loaded novel temperature-sensitive liposomes / 中国药学杂志

OBJECTIVE: To optimize the prescription of the novel temperature-sensitive liposomes(NTSL). METHODS: Calcein-loaded temperature-sensitive liposomes with different phospholipid composition (DPPC-MSPC-DSPE-PEG200=86:10:4 and N (20% HSPC + 80% DPPC) -MSPC-DSPE-PEG200=92:4:4) were prepared by the thin film -hydration method. Based on the fluorescence self-quenching off characteristics of calcein, the release behavior of the above liposomes was compared when exposed to 37°C (normal temperature) as well as their respective phase transition temperature (Tm). RESULTS: Compared with the traditional temperature-sensitive liposomes (TTSL), the NTSL showed more favorable temperature-sensitive release performance and more stable encapsulation ability to calcein, even with the amount of lysophospholipids was reduced by 60 percent. CONCLUSION: The application of NTSL helps to enhance the effect of temperature-sensitive release.

Study on preparation and thermosensitive release property of composite phospholipid liposomes containing total alkaloids from Strychnos nux-vomica / 中国中药杂志

To prepare composite phospholipid liposomes containing total alkaloids of Strychnos nux-vomica with hydrogenated soybean phosphatidylcholine (HSPC) and 1, 2-dipalmitoyl-sn-glycero-3-phosphacholine (DPPC), and compare with normal DPPC thermosensitive liposomes for thermosensitive release property. Total alkaloids were extracted from S. nux-vomica with the impregnation method and further purified. Liposomes containing total alkaloids, thermosensitive liposomes and conventional thermosensitive liposomes without thermosensitive release property were prepared by ammonium sulfate transmembrane gradients and stealth liposome technique. Their encapsulation efficiency (EE), grain size, zeta potential and drug release behavior were compared. Their EEs and zeta potentials were almost identical; but the grain sizes of composite phospholipid liposomes and thermosensitive liposomes were significantly smaller than conventional liposomes. After comparing release behaviors of the three liposomes at 37, 43 degrees C, we found that the release of composite phospholipid liposomes was significantly lower than that of thermosensitive liposomes at 37 degrees C, but higher than that of thermosensitive liposomes at 43 degrees C. Meanwhile, conventional liposomes, with a very high phase-transition temperature, showed only slight release behavior at both temperatures. The study results showed that composite phospholipid liposomes had a better thermosensitive release behavior when the dosage of lysophosphatidic was reduced by 2. 5 times.