Naproxen sodium Chemical Properties Melting point 250-251°C alpha D -11° (in methanol) storage temp. Desiccate at RT solubility Freely soluble in water, freely soluble or soluble in methanol, sparingly soluble in ethanol (96 per cent). form neat Water Solubility Soluble in water up to 100mg/mlSoluble in methanol and chloroform. Slightly soluble in ether. Insoluble in water.