Fast-Dissolving and High-Drug-Loaded, Fatty Acid–Based Self-Emulsifying Solid Dispersions of Diacerein

Abstract

The purpose of the present study was to enhance the solubility and dissolution of diacerein by preparing their fatty acid–based, self-emulsifying solid dispersions (SDs) containing polyethylene glycol 6000 (PEG 6000), surfactant, and self-emulsifying excipient with high drug content. Ternary and self-emulsifying SDs containing high drug content were prepared and characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy, solubility studies, and dissolution studies. When hydrophilic and lipophilic excipients were combined and incorporated into PEG 6000–based SDs, a remarkable enhancement of the dissolution rate was observed, even in SDs with high drug content. The presence of surfactant and self-emulsifying excipient did not affect the solid state characterization of the drug. The decrease in the intensity of the numerous distinctive peaks of the drug in the PXRD spectra and absence of drug melting peak in DSC spectra demonstrated that a high concentration of the drug molecules was dissolved in the solid-state carrier matrix. The utilization of self-emulsifying excipient and surfactant in PEG 6000–based SDs could be a useful tool to enhance the dissolution and bioavailability of diacerein by forming solubilizing and microemulsifying systems with high drug content.

LAY ABSTRACT: The purpose of the present study was to enhance the solubility and dissolution of diacerein by preparing their fatty acid–based, self-emulsifying solid dispersions with high drug content. These solid dispersions were prepared and characterized by powder X-ray diffraction, differential scanning calorimetry, Fourier transform infrared spectroscopy, solubility studies, and dissolution studies. When hydrophilic and lipophilic excipients were combined and incorporated into PEG 6000–based solid dispersions, a remarkable enhancement of the dissolution rate was observed, even in solid dispersions with high drug content. Moreover, the presence of surfactant and self-emulsifying excipient did not affect the solid state characterization of the drug. The decrease in the intensity of the numerous distinctive peaks of the drug in the powder X-ray diffraction spectra and absence of drug melting peak in the spectra obtained by differential scanning calorimetry demonstrated that a high concentration of the drug molecules was dissolved in the solid-state carrier matrix.