title: Comparative studies on the properties of glycyrrhetinic acid-loaded PLGA microparticles prepared by emulsion and template methods.
abstract: The O/W emulsion method has been widely used for the production of poly (lactide-co-glycolide) (PLGA) microparticles. Recently, a template method has been used to make homogeneous microparticles with predefined size and shape, and shown to be useful in encapsulating different types of active compounds. However, differences between the template method and emulsion method have not been examined. In the current study, PLGA microparticles were prepared by the two methods using glycyrrhetinic acid (GA) as a model drug. The properties of obtained microparticles were characterized and compared on drug distribution, in vitro release, and degradation. An encapsulation efficiency of over 70% and a mean particle size of about 40μm were found for both methods. DSC thermograms and XRPD diffractograms indicated that GA was highly dispersed or in the amorphous state in the matrix of microparticles. The emulsion method produced microparticles of a broad size distribution with a core-shell type structure and many drug-rich domains inside each microparticle. Its drug release and matrix degradation was slow before Day 50 and then accelerated. In contrast, the template method formed microparticles with narrow size distribution and drug distribution without apparent drug-rich domains. The template microparticles with a loading efficiency of 85% exhibited a zero-order release profile for 3 months after the initial burst release of 26.7%, and a steady surface erosion process as well. The same microparticles made by two different methods showed two distinguished drug release profiles. The two different methods can be supplementary with each other in optimization of drug formulation for achieving predetermined drug release patterns.
authors.affiliation: Department of Pharmaceutics, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia 750004, China.
authors.forename: Guangxing
authors.initials: G
authors.lastname: Zhang
authors.affiliation: School of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia 750004, China; Ningxia Engineering and Technology Research Center for Modernization of Hui Medicine & Key Lab of Hui Ethnic Medicine Modernization, Ministry of Education, Yinchuan, Ningxia 750004, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Sui
authors.affiliation: School of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia 750004, China; Ningxia Engineering and Technology Research Center for Modernization of Hui Medicine & Key Lab of Hui Ethnic Medicine Modernization, Ministry of Education, Yinchuan, Ningxia 750004, China.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Departments of Biomedical Engineering and Pharmaceutics, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Kinam
authors.initials: K
authors.lastname: Park
authors.affiliation: School of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia 750004, China; Ningxia Engineering and Technology Research Center for Modernization of Hui Medicine & Key Lab of Hui Ethnic Medicine Modernization, Ministry of Education, Yinchuan, Ningxia 750004, China. Electronic address: wpwang2015@163.com.
authors.forename: Wenping
authors.initials: W
authors.lastname: Wang
mesh_terms: D002626:Chemistry, Pharmaceutical; D004655:Emulsions / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D006034:Glycyrrhetinic Acid / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D019344:Lactic Acid / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D008863:Microspheres; D010316:Particle Size; D011100:Polyglycolic Acid / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D014961:X-Ray Diffraction
chemical_list: D004655:Emulsions; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D006034:Glycyrrhetinic Acid
keywords: Glycyrrhetinic acid; Hydrogel template method; O/W emulsion method; PLGA microparticles