Drug–Smectite Clay Amorphous Solid Dispersions Processed by Hot Melt Extrusion

The aim of this study was to investigate suitability of natural and synthetic smectite clay matrices as a drug delivery carrier for the development of amorphous solid dispersions (ASD). Indomethacin (IND) was processed with two different smectite clays, natural-magnesium aluminium and synthetic-lithium magnesium sodium silicates, using Hot Melt Extrusion (HME) to prepare solid dispersions. Scanning electron microscopy (SEM), Powdered X-ray diffraction (PXRD), Differential scanning calorimetry (DSC) were used to examine the physical form of the drug. Energy dispersive X-ray spectroscopy (EDX) was used to investigate the drug distribution and Attenuated Total Reflectance-Fourier transform infrared (ATR-FTIR) spectroscopic analysis was done to detect any chemical interaction between these two kinds. Both, PXRD and DSC analysis showed that drug-clay solid dispersion contained IND in amorphous form. Energy dispersive X-ray (EDX) analysis showed a uniform IND dispersion in the extruded powders. ATR-FTIR data presented possible drug and clay interactions via hydrogen bonding. In-vitro drug dissolution studies revealed a lag time of about two hours in the acidic media and a rapid release of IND at pH 7.4. The work demonstrated that preparation of amorphous solid dispersion using inorganic smectite clay particles can effectively increase the dissolution rate of IND.