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Objective: To prepare pegylated long-circulating liposomes co-encapsulated by costunolide (Cos) and dehydrocostus lactone (DL), optimize the formulation and process, and evaluate the quality. Methods: The pegylated long-circulating liposomes co-encapsulated by Cos and DL were prepared by film hydration method. Single factor test and Box-Behnken response surface methodology were used to optimize the preparation process with encapsulation efficiency of Cos and DL as the index. The particle size, surface potential, encapsulation efficiency and in vitro release of the liposomes were evaluated. Results: The optimal preparation conditions were as follows: drug-to-lipid ratio was 0.14, ratio of cholesterol to phospholipid was 0.05, mPEG-2000-DSPE addition amount was 6%, hydration time was 30 min, and probe ultrasonic time was 4 min. The obtained liposome was round and uniform in distribution, with an average particle size of (104.8 ± 2.48) nm, a polydispersity index (PDI) of (0.245 ± 0.031), and a Zeta potential of (-9.7 ± 0.23) mV, the encapsulation efficiency of Cos and DL were (91.9 ± 2.6)% and (94.41 ± 1.23)%, respectively. Conclusion: The PEGylated long-circulating liposome prepared by the process and prescription optimization has good appearance and high encapsulation efficiency, which can meet the application requirements.
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The therapeutic application of artemisinin (ART) is restricted in application due to its poor water solubility and stability. In this study, the long-circulating liposomes (L-Lip) were constructed to improve the solubility and stability of ART. The preparation method, physicochemical properties, serum stability, in vitro release profile and cytotoxicity of the ART loaded long-circulating liposomes were investigated. Using the particle size and entrapment efficiency (EE) as the evaluation index, the preparation procedure was optimized by the Box-Behnken response surface design based on the single factor screening method. The ART loaded long-circulating liposomes were prepared by filming rehydration method, and evaluated with particle size and entrapment efficiency. The optimal formulation was as follows:lipid-cholesterol=5.22:1 (mass ratio), drug-lipid=1:23.15 (mass ratio), lipid concentration=14.35 mg·mL-1, and molar percentage of mPEG=2%. The morphology of L-Lip was uniformly spherical shape according to optimal formulation. The mean size and polydispersity index (PDI) were about (113.3 ±4.7) nm and 0.227 ±0.022 respectively, the zeta potential was (-12.9 ±2.6) mV, and the entrapment efficiency (EE) of ART was (95.88 ±4.8)%. The L-Lip had good stability at 4℃ for 15 days and the particle sizes did not exhibit significant variations in 50% rat plasma over 24 h at 37℃. The in vitro release study of formulation showed a sustained release. Moreover, the cytotoxicity exhibited that blank liposomes were of great safety. Compared with the free ART, the liposome formulation achieved lower cytotoxicity at the high concentration. The L-Lip successfully prepared by a simple filming-rehydration method exhibited ideal physicochemical properties and were enhanced safety, which may sever as a promising nanoplatform for clinical application.
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OBJECTIVE:To prepare Coenzyme Q10 long-circulating liposomes,establish the determination method of content and entrapment efficiency,and prepare it into lyophilized preparation to improve its stability. METHODS:Coenzyme Q10 long-cir-culating liposomes were prepared by film dispersion method. Particle size and Zeta potential of liposomes were determined,and HPLC assay was used to determine the content of coenzyme Q10. Free drugs and liposomes were separated using protamine aggre-gation method,and the encapsulation efficiency was calculated. Lyophilized preparation was prepared by coenzyme Q10 long-circu-lating liposomes,and the changes of content and encapsulation efficiency of drugs were determined 0,30 and 90 days after lyophi-lization. RESULTS:The liposomes were homogeneous in size with mean diameter of(166.0±5.3)nm and Zeta potential of(-22.2± 1.4)mV. Average content(the percentage of content accounted for labeled amount)and entrapment efficiency of 3 batches of sam-ple were 98.2%(RSD=2.8%) and 93.2%(RSD=4.6%),respectively. Compared with 0 d after lyophilization,coenzyme Q10 long-circulating liposomes had no obvious change in the content and encapsulation efficiency 90 d after lyophilization. CONCLU-SIONS:Coenzyme Q10 long-circulating liposomes with high quality and entrapment efficiency and lyophilized preparation being stored stably for 90 d have been prepared successfully.
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Objective To improve the stability of epirubicin long circulation liposomes via lyophilizing technology and preliminarily evaluate their quality. Methods The effect of the various cryoprotectant,different pre-freezing and total drying time on the preparation was analyzed. The stability of the lyophilized powder was tested at (25±2) ℃ and (60±10)% relative humidity for 3 months. Results The protective agent trehalose to liposomes was 31. The freeze-drying was conducted with pre-freezing temperature at -70 ℃,precooling for 8 h and total drying for 24 h. There were no significant differences in particle size,encapsulation efficiency and drug content of lyophilized long-circulating liposomes compared with those un-lyophilized. After 3 months under the accelerated condition,it had good redispersibility, entrapment rate (>94%) and drug content (>99%) . Conclusion Lyophilizing the long-circulation epirubicin liposomes can effectively improve the stability of the preparation.
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Objective To establish a method for the preparation of long-circulating liposomes (LCL) containing etoposide and to observe its stability in rats plasma.Methods The etoposide-containing liposome was prepared by ethanol injection method. Polyethylene glycol-distearoyl phosphatidylethanolamine (PEG2000-DSPE) was used to modify the membrane of the liposome. Reversed-phase high pressure liquid chromatography (RP-HPLC) was used to detect the concentration of the liposome,and dynamic release method was used to study its stability in mice plasma.Results The mean size of the LCL containing etoposide was (180?26) nm,and the mean concentration of etoposide was (4.78?0.22) mg/mL,with the entrapment efficiency being (88.71?8.2)%. The leakage ratio of the conventional liposome containing etoposide and LCL containing etoposide in mice plasma were (80.14?1.59)% and (46.72?2.61)%,respectively.Conclusion LCL containing etoposide with high entrapment efficiency and low leakage rate can be obtained by using ethanol injection method. Additionally,modification by PEG2000-DSPE could raise the stability of the liposome.
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Objective To prepare the Polyporus umbellatus polysaccharides (PUPS) long cirrculating liposomes (LCLs) and to study the quality control of PUPS LCLs. Methods The PUPS LCLs were prepared by chloroform infusion combined with the ammonium sulphate gradient method. The content and encapsulation efficiency of PUPS in LCLs were determined by UV-Sephadex method. Results Mean diameter of the PUPS LCLs was 100 nm, with the encapsulation efficiency of 55.3%. Conclusion The LCLs with high encapsulation efficiency and small particle size could be prepared by chloroform infusion combined with the ammonium sulphate gradient method. UV-Sephadex method is suitable for the quality control of PUPS LCLs and the results are reliable.