Miscibility and Interactions between 17-estradiol and Eudragit (R) RS in Solid Dispersion

作者：Wiranidchapong Chutima; Tucker Ian G; Rades Thomas; Kulvanich Poj^*

来源：Journal of Pharmaceutical Sciences, 2008, 97(11): 4879-4888.

DOI：10.1002/jps.21366

• drug-polymer blends
• miscibility
• solid-state interactions
• Flory-Huggins theory
• Nishi-Wang equation
• Gordon-Taylor equation
• Kwei equation
• MTDSC
• XRPD
• FTIR

Miscibility of 17-estradiol and Eudragit (R) RS in solid dispersions was determined by modulated temperature differential scanning calorimetry (MTDSC). A reduction of the 17-estradiol melting point in Eudragit (R) RS solid dispersions was observed by MTDSC using heating program I in which the maximum temperature in the first heating run was lower than the 17-estradiol melting point. The melting point depression of 17-estradiol in solid dispersions as a function of composition could be explained by the Nishi-Wang equation indicating an interaction between 17-estradiol and Eudragit (R) RS in the system. A variation of glass transition temperature (T-g) of 17-estradiol in Eudragit (R) RS solid dispersion was observed by MTDSC using heating program II in which the maximum temperature in the first heating run reached the 17-estradiol melting point. In the second heating run of heating program II, 17-estradiol was in an amorphous form blended with Eudragit (R) RS. The variation in T-g of amorphous 17-estradiol blended with Eudragit (R) RS could be explained by the Kwei equation, a modified version of the Gordon-Taylor equation. The parameter estimates from the Kwei equation were consistent with an interaction between 17-estradiol and Eudragit (R) RS, which was due to inter-associated hydrogen bonding as deduced from the FTIR spectra of the blends.

• 出版日期2008-11