Solidification of carvedilol loaded SMEDDS by swirling fluidized bed pellet coating

Self-(micro)emulsifying drug delivery systems (S(M)EDDS) have emerged as effective vehicles for enhancing bioavailability of poorly water soluble drugs, however solidification of the systems represents a major challenge. Objective of this study was development of carvedilol loaded liquid SMEDDS and transformation into solid pellets employing fluid-bed coating technologies. Carvedilol-loaded formulation of SMEDDS was comprised of Capmul® MCM EP, castor oil, Kolliphor® RH40 and PEG 400. The obtained liquid SMEDDS mixed with fillers and polymers was layered onto MCC pellets. Coating process was conducted in the modified, swirl-flow based fluid bed coating device, which was proved superior over the conventional Wurster fluid bed, with lower agglomeration rate. Use of polymer was essential for entrapping SMEDDS in the coating layer(s). Self-microemulsifying properties as well as fast drug release as one of main SMEDDS advantages were preserved in the solid products. Addition of lactose into the coating dispersion and applying intermediate and surface film coating to the pellets enabled higher drug loading and prevented sticking of the pellets during handling and storage. Present study indicates that the (swirling) fluid-bed pellet coating technology is a promising strategy for preparation of solid SMEDDS-coated pellets with adequate drug loading capacity and enhanced release of poorly water soluble drug.