title: Characterization of solid dispersions of Patchouli alcohol with different polymers: effects on the inhibition of reprecipitation and the improvement of dissolution rate.
abstract: Solid dispersion technique is known to be an effective approach for the polymer to keep drugs stable in the solid state, thereby improving the dissolution rate and oral bioavailability through inhibiting reprecipitation in supersaturated solution. In this study, to evaluate the inhibitory effect of polyethylene glycol-6000 (PEG), Polyvinylpyrrolidone K30 (PVP) and Aminoalkyl methacrylate copolymer (Eudragit), the reprecipitation profiles were observed from supersaturated solutions of Patchouli alcohol (PA) in the presence and absence of the polymers. Furthermore, the dissolution profiles of PA solid dispersions formulated with PEG, PVP or Eudragit were compared for investigating the effect on improving dissolution of each polymer. Solid dispersions formulated with Eudragit were found to result in solution with the highest extent of supersaturation. By contrast, PEG and PVP were less effective. At equivalent supersaturation, all three polymers are capable of mitigating reprecipitation relative to that of PA alone. In addition, in the PA solid dispersion with Eudragit (E-SD (1/3)), the highest concentration of supersaturation of PA was maintained for prolonged time. These results unambiguously indicate that it is imperative to select the appropriate polymer and drug/polymer ratio in addition to considering the stability of the supersaturated solution, which was generated following dissolution of amorphous solid dispersion.
authors.affiliation: School of Chinese Materia Medica, Guangzhou University of Chinese Medicine , Guangzhou , China .
authors.forename: Yun Long
authors.initials: YL
authors.lastname: Chen
authors.forename: Jin Bin
authors.initials: JB
authors.lastname: Liao
authors.forename: Yong Zhuo
authors.initials: YZ
authors.lastname: Liang
authors.forename: Jian Hui
authors.initials: JH
authors.lastname: Xie
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wu
authors.forename: Xiao Ping
authors.initials: XP
authors.lastname: Lai
authors.forename: Jian Nan
authors.initials: JN
authors.lastname: Chen
authors.forename: Zi Ren
authors.initials: ZR
authors.lastname: Su
authors.forename: Zhi Xiu
authors.initials: ZX
authors.lastname: Lin
mesh_terms: D002152:Calorimetry, Differential Scanning / Q000379:methods; D011232:Chemical Precipitation; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D012717:Sesquiterpenes / Q000737:chemistry* / Q000378:metabolism; D012995:Solubility
chemical_list: D011108:Polymers; D012717:Sesquiterpenes; C052983:patchouli alcohol
keywords: Amorphous; Patchouli alcohol; dissolution; reprecipitation; solid dispersion