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.

• Amorphous
• dissolution
• Patchouli alcohol
• reprecipitation
• solid dispersion

Declaration of interest

This work was supported by grants from the Guangdong International Cooperation Projects in 2012, Guangdong Province, P.R. China (Project No. 2012B050300002), and the National Natural Science Foundation of China (Project No. 81173534), National Science Foundation of China (No. 81374043), Science and Technological Program for Dongguan’s Higher Education, Science and Research, and Health Care Institutions (No. 2012105102009). The authors declare that there are no conflicts of interest.