Spray drying from complex solvent systems broadens the applicability of Kollicoat IR as a carrier in the formulation of solid dispersions

The presented study aims to explore the feasibility of preparing solid dispersions of the poorly soluble drug, itraconazole, with Kollicoat IR via spray drying, in order to broaden the application window of the polymer. In order to circumvent the need for a common solvent, Kollicoat IR was dissolved in a 50/50 (v/v) water/ethanol mixture and itraconazole was dissolved in a 50/50 (v/v) dichloromethane/ethanol mixture. In a first approach these two solutions were simultaneously spray dried via a spray nozzle with two inlets. In a second approach the two solutions were mixed prior to spray drying and the metastable solution was spray dried via a spray nozzle with a single inlet. This approach was also varied by adding HCl to the water phase of the Kollicoat IR solution. The resulting solid dispersions were characterized with MDSC, XRPD and their dissolution was followed in SGF. The results of the three data sets show that as the mixing between itraconazole and Kollicoat IR improves, the dissolution improves as well. Using the first approach, no mixing was observed between polymer and drug. The second approach on the other hand led to a reasonable degree of mixing as the solid dispersions were XRPD amorphous and no glassy mesofase of itraconazole was observed.