Combining of Spray Drying and Dry Granulation to Prepare Orodispersible Tablets: Influence of Spray-Dried Particle Size on Tablet Properties.

The study investigated how the particle size of spray-dried powders containing a model drug and hypromellose phthalate incorporated to granules impacts the powder flow properties, compressibility, and tablet properties. The spray-dried products were obtained at 3 different atomizing gas flow rates and then incorporated into three tabletting materials using dry granulation. The granulation step increased powder bulk and tap density, and decreased Hausner ratio and compressibility index. The particle size of the spray-dried powder influenced the compressibility of granulated tabletting materials and the tensile strength, friability and wetting time of the tablets. The granules with the largest spray-dried particles showed the highest plastic deformation energy, the highest tensile strength and the lowest friability of tablets. Tablets prepared from all granulated powders had a disintegration time below 3 min (European pharmacopeial limit for orodispersible tablets). The tablets also exhibited immediate-release dissolution profiles, and the dissolution rate accelerated with decreasing particle size. Our results imply that gas flow rate during spray drying affects spray-dried particle size and, consequently the properties of granulated powders, the tabletting process and the final tablet quality. We found well-suited mixture composition and processing conditions enabling the preparation of orodispersible tablets with an immediate-release drug dissolution profile.