Preparation of solid dispersions with respect to the dissolution rate of active substance

Abstract Solid dispersions (SDs) are one of the successfully applied methods to improve the solubility and dissolution rates of poorly water-soluble drugs. SDs are commonly API-polymer systems, where API is molecularly dispersed in a polymeric matrix. The objective of this study was to prepare SDs by different techniques and with different polymeric matrices and compare them with the physical mixtures in terms of dissolution properties. Tadalafil was used as a model poorly water-soluble drug, which was combined with hydrophilic polymers Kollidon® 12 PF, Kollidon® VA 64 and Soluplus®. Our results show that as the molecular weight of polymer increased, hydrophilic polymer swelled more during the dissolution and on the contrary, the drug release decreased. In this case, it means, that the presence of both Kollidons has a positive effect on the acceleration of tadalafil release, on the other hand, the presence of Soluplus® retarded its release. The apparent intrinsic dissolution measurements were used to separate the dissolution effects from those related to particle size. These results indicate the possibility of different applications of SDs in pharmaceutical formulations, based on careful selection of the polymer co-former and it might be useful for the drug tailoring.