Effect of pH Modifiers on the Solubility, Dissolution Rate, and Stability of Telmisartan Solid Dispersions Produced by Hot-melt Extrusion Technology.

The aim of the current study was to investigate the dual effect of an amorphous solid dispersion generated by hot melt extrusion and the addition of pH modifiers on the solubility and stability of telmisartan. Hydroxypropyl methylcellulose acetate succinate L grade was used as a polymeric carrier and recrystallization inhibitor, and meglumine, sodium carbonate, or Neusilin S2 were incorporated as pH modifiers to generate a desirable microenvironmental pH in the solid dispersions. Differential scanning calorimetry, powder X-ray diffraction, and Fourier transform infrared spectroscopy were incorporated to obtain the solid-state characterizations of telmisartan, and the results confirm a partial transformation of telmisartan to an amorphous state. An in vitro release study revealed that the transformation of telmisartan to an amorphous material improved its dissolution rate by 2-fold compared to pure drug and by up to 5-fold with the incorporation of pH modifiers. Results of the stability studies demonstrated that the samples have no significant degradation under accelerated stability conditions at 40 °C/75% RH.