Spray drying processes for forming solid amorphous dispersions of low-solubility drugs and polymers

Spray drying processes are used to form pharmaceutical compositions comprising a solid amorphous dispersion of a drug and a polymer. Particularly disclosed is a process for forming a pharmaceutical composition comprising a solid amorphous dispersion comprising a drug and a polymer, comprising the steps of: (a) providing a drying apparatus having an atomizer connected to a drying chamber, said drying chamber having an inlet and an outlet; (b) forming a spray solution by dissolving said low-solubility drug and said polymer in a solvent, wherein said polymer is selected from the group consisting of hydroxypropyl methyl cellulose acetate succinate, hydroxypropyl methyl cellulose, hydroxypropyl methyl cellulose phthalate, carboxy methyl ethyl cellulose, cellulose acetate phthalate, and cellulose acetate trimellitate; (c) spraying said spray solution through said atomizer into said chamber to form droplets having a volume average size of less than 500 micrometers; (d) flowing a drying gas through said inlet at a flow rate and a temperature TIN such that said droplets solidify in less than about 20 seconds to form said solid amorphous dispersion of said low- solubility drug in said polymer; (e) wherein said solid amorphous dispersion of said low-solubility drug in said polymer provides either concentration enhancement or faster dissolution of said low-solubility drug in an aqueous use environment relative to a control composition consisting of said low-solubility drug alone; wherein a feed rate of said spray solution is at least 10 kg/hr, and said feed rate of said spray solution and said TIN of said drying gas are controlled so that said drying gas at said outlet has a temperature TOUT, and said TOUT is less than said boiling point of said solvent; and wherein said drying gas further comprises said solvent in vapour form.