Morphological and in vitro investigation of core–shell nanostructures of carvedilol using quality by design

Abstract

The present study aimed to develop an ideal nanostructured delivery (propylene glycol monocaprylate-polycaprolactone core–shell nanostructures) for a poorly soluble drug by quality-by-design (QbD) approach. Carvedilol (CVD) loaded polymeric nanocapsules were formulated by 32 factorial designs and established the functional relationships between the operating independent variables. An increase in polycaprolactone (PCL) content led to a rise in mean particle size, while the effect of Lutrol F127 was found statistically insignificant. Furthermore, it was observed that as the level of Lutrol F127 increases zeta potential decreases. However different levels of PCL did not significantly affected the zeta potential. The in vitro release of carvedilol from nanocapsule is contributed by the coupling of diffusion and erosion mechanism. Scanning electron microscopy, transmission electron microscopy (TEM) and atomic force microscopy (AFM) images showed the spherical nature of prepared optimized formulations OF1–OF3. TEM images illustrated spherical nanocapsules with a clearly distinctive oil core and PCL coating. The thickness of the core varied from 14.78 to 54.21 nm. The smooth surface of nanocapsules observed under AFM studies indicated no surface crystallization of CVD or other excipients used in preparing optimized formulations. The root mean square roughness and the average volume of optimized nanocapsules (OF1–OF3) ranged between 14.42–23.26 nm and 24.41–49.91 µm3, respectively. This study revealed the effectiveness of QbD for the preparation of optimized nanocapsules of CVD having desired attributes in the shortest possible time.