Abstract: The invention provides a method of making a pharmaceutical composition comprising a solution, which method comprises: (a) providing a solvent comprising propylene glycol, polyethylene glycol, polypropylene glycol, or glycerin; and (b) adding metolazone. The final concentration of metolazone in the solution is 9 mg/ml or more, the metolazone is not precipitated, and the concentration of metolazone is above its apparent equilibrium solubility. The invention also provides a pharmaceutical composition comprising a solution comprising: (a) a solvent other than water; and (b) 9 mg/ml or more of metolazone. The metolazone is not precipitated in this solution and the concentration of metolazone is above its apparent equilibrium solubility.

Abstract: The invention provides a pharmaceutical composition comprising a drug-resin complex and a chelating agent in which the composition is in the form of a solid or a gel. The invention also provides a method of making such a composition and a method for improving the stability of a pharmaceutical composition.