Dissolution properties and anticonvulsant activity of phenytoin-polyethylene glycol 6000 and -polyvinylpyrrolidone K-30 solid dispersions.

Solid dispersions of phenytoin in polyethylene glycol 6000 and polyvinylpyrrolidone K-30 with different drug-to-carrier ratios were prepared by the solvent method with the aim of increasing dissolution rate and bioavailability of the drug. These new formulations were characterized in the solid state by FT-IR spectroscopy, X-ray powder diffraction, and differential scanning calorimetry. Drug solubility and dissolution rate are improved by these formulations, particularly with SDPEG 1/20 and SDPVP 1/20 systems. Storage was found to influence the stability of the solid dispersions. By maximal electroshock test, it was found that the intraperitoneal administration in mice of the SDPEG 1/20 and SDPVP 1/20 systems exhibited anticonvulsant activity similar to diphenylhydantoin sodium salt.