[Liposomal encapsulation of free anthraquinones in rhizoma et radix rhei and its quality control].
OBJECTIVE
To encapsulate the free anthraquiones in Rhizoma et Radix Rhei (rhein, chrysophanol, physcione, emodin and aloeemodin) in liposomes and characterize the liposomes.


METHODS
The liposomes were separated from free drug with sephadex G-50 with HPLC determination of the free anthraquinones in liposomes, then its entrapment efficiency was calculated. Ethanol injection method was used to prepare the liposomes with the addition of a suitable amount Ca2+ in the medium. The influence of Ca2+ on the entrapment efficiency of free anthraquinones in Rhizoma et Radix Rhei in liposomes has been studied. Dynamic laser scatterometer and transmission electron microscopy were used to study the sizes and morphology of the liposomes.


RESULTS
The entrapment efficiency of rhein, chrysophanol, physcione, emodin and aloeemodin in liposomes were 27.63%, 85.16%,100.14%, 99.77% and 66.16%, respectively. The total entrapment efficiency of free anthraquinones in Rhizoma et Radix Rhei was 80.67%. Ca2+ could greatly promote the liposomal encapsulation of free anthraquinones in Rhizoma et Radix Rhei from 13.98% - 23.78% to 81.42% - 89.43%. The liposomes were white spheres and its average size was mainly concentrated on 340 nm.


CONCLUSIONS
The entrapment efficiency of the liposomal encapsulation of free anthraquinones in Rhizoma et Radix Rhei is high. The quality control method is simple and rapid with good repeatability.
Suo
Xu-Bin
XB
Institute of New Drug Development of TCM, Guang Dong Pharmaceutical University, Guangzhou 510006, China. suoxubin04@yahoo.com.cn
Liu
Yan
Y
Wu
Yan-Hong
YH
Li
Yuan-Xin
YX
D000880:Anthraquinones / Q000008:administration & dosage* / Q000032:analysis / Q000737:chemistry; D002118:Calcium / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004337:Drug Carriers; D004355:Drug Stability; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D004642:Emodin / Q000031:analogs & derivatives / Q000032:analysis; D008081:Liposomes / Q000737:chemistry*; D010316:Particle Size; D011786:Quality Control; D015203:Reproducibility of Results; D012250:Rheum / Q000737:chemistry*; D027343:Rhizome / Q000737:chemistry
D000880:Anthraquinones; D004337:Drug Carriers; D004365:Drugs, Chinese Herbal; D008081:Liposomes; C518327:aloe emodin; C008905:physcione; D004642:Emodin; C027113:chrysophanic acid; D002118:Calcium; C020491:rhein