DISSOLUTION PROPERTIES OF NAPROXEN IN COMBINATIONS WITH POLYVINYLPYRROLIDONE

The effect of the molecular weight of polyvinylpyrrolidone on the solubility and dissolution properties of naproxen using solid dispersions (coevaporates and colyophilized products) and physical mixtures was investigated. Factors such as method of drug incorporation with the polymer and polymer mass fraction influence the dissolution rate of naproxen from both powders and constant surface area discs. The best results were obtained with the colyophilized products at the drug-to-polymer 7:3 weight ratio, in the rank order (most effective to least) K15>K30>K90 (dispersed amount) and K30>K90>K15 (rotating disc). The physical state of naproxen, ie. amorphous or crystalline, in solid combinations with polyvinylpyrrolidone was checked by means of X-ray powder diffraction. Drug-polymer interactions in the liquid state were revealed with solubility experiments. Drug-polymer interactions in solid state were demonstrated by combining the X-ray diffraction data with the results of thermal analysis (DSC, TGA) and microscopic observation.