Preparation Of Curcumin Liposome By Ammonium Sulfate Gradient Method And Investigation On Its Anti-tumor Capacity

Curcumin is a promising polyphenol compound extracted from curcuma longa,which is a member of ginger family.Extensive researches have proven that this polyphenol compound has multiple potentialities for various medical applications.However,due to its poor solubility in water,and it is only soluble in organic solvents such as ethanol,chloroform,glacial acetic acid,etc.,making it difficult for Cur to be further promoted in clinical practice.The ammonium sulfate gradient method can load a weakly basic drug into the liposome to obtain a high drug-loaded liposome.Curcumin liposomes（Cur-PEG-LPs）were prepared by ammonium sulfate gradient method to increase cell uptake,enhance anti-tumor effect in vitro,and improve pharmacokinetic behavior,but could not inhibit growth of 4T1 tumors in Balb/c mice.Objective:Curcumin（Cur）PEGylated liposomes（PEG-LPs）were prepared by ammonia sulfate gradient method to elevate drug loading capacity.Anti-cancer capacity of Cur-PEG-LPs in vitro and in vivo was studied.Methods:Liposomes was prepared by the extrusion technique and PEGylation was accomplished by post-attach method.Curcumin was loaded into PEG-LPs by ammonia sulfate gradient method with acetic acid as cosolvent and purified by sephadex G-50column.Then the formation was characterized by Dynamic Light Scattering（DLS）,Differential Scanning Calorimeter（DSC）,and powder X-ray diffractometry（PXRD）;the cytotoxicity in vitro was detected by MTT assay,and pharmacokinetic in vivo was tested by HPLC in rats after intravenous injection;4T1 tumor-bearing mice model was successfully established and used to perform pharmacodynamics in vivo;biodistribution of curcumin in major organ and tumor after intravenous administration was assayed by HPLC.Results:Cur was successfully encapsulated into the PEG-LPs with encapsulation efficiency（EE）of 45.8%and drug loading capacity（DL）of 5.6%.The average size of Cur-PEG-LPs was 203.3±16.1 nm with polydispersity index（PDI）of 0.269±0.018.Cur-PEG-LPs improved solubility of curcumin in water so that it facilitated cellular up-take process.IC₅₀0 for 24 h incubation decreased from 28.15μg/mL to 16.99μg/mL,which suggested the enhancement of anti-tumor capacity.Cur-PEG-LPs also ameliorated pharmacokinetic behavior of curcumin in rats.Both Cur and Cur-PEG-LPs could not inhibit 4T1 tumor growth on the tumor-bearing mice after intravenous administration at the dose of 10 mg/kg.Biodistribution assay showed that amounts of curcumin accumulated in the lung while trace of curcumin delivered into the tumor.Conclusion:The Cur-PEG-LPs can be successfully prepared by ammonia sulfate gradient method to enhance drug loading capacity 2-fold higher compared with thin-film method.And Cur-PEG-LPs may be a promising therapeutic preparation for lung cancer.