DISSOLUTION RATE OF DIAZEPAM FROM POLYETHYLENE-GLYCOL 6000 SOLID DISPERSIONS

A method for the elaboration of solid dispersions, the weight ratios of diazepam to polyethylene glycol 6000 and the particle size of drug in the solid dispersion have been investigated. The preparation method and diazepam-polyethylene glycol 6000 ratio influence the dissolution rate of the drug. It is observed that faster release characteristics were obtained with solid dispersions prepared by the fusion method and by increasing the carrier percentage. The increase in dissolution rate can be considered to result from crystal size reduction and the solubilizing effect of polyethylene glycol 6000. An intrinsic effect of the carrier also increases the dissolution rate of diazepam, since a physical mixture of the same composition dissolves more slowly than the solid dispersions. It is concluded that such a difference must be attributed to a significant reduction of the drug particle size in the carrier matrix.