A comparison of alternative polymer excipients and processing methods for making solid dispersions of a poorly water soluble drug.

Solid dispersions were prepared with the extremely poorly water soluble drug, probucol and the water soluble polymers, polyvinyl pyrrolidone (PVP), polyacrylic acid (PAA) or polyethylene oxide (PEO) and blends of these polymers. The solid dispersions were prepared either by the solvent evaporation method, or by compression moulding into films. The materials were characterised by a combination of thermal analysis and FT-Raman spectroscopy. The physical state of the drug was observed to be dependent on the carrier, thus the PVP solid dispersions contained amorphous probucol, whilst the PAA and PEO systems contained the crystalline polymorph II. The method of production was not found to greatly influence the state of the drug in the solid dispersion. The greatest extent of release into solution was observed for the binary blend of drug and PEO, and the blending of polymers was not found to have any advantageous effects in this study.