Implementation of Quality by Design (QbD) concept for the development of emulsion based nanotailored gel for improved antiphotoageing potential of Silymarin

Silymarin is a powerful free radical scavenger, anti-inflammatory and immune system modulating agent which can be effectively used for the treatment of various skin ailments. The present research work emphasizes on establishing the antiphotoageing potential of Silymarin biochemically followed by the development of a nanotailored topical carrier system of Silymarin for its improved therapeutic effect by enhancing its skin retention and minimizing systemic delivery. Silymarin laden nanoemulsion was formulated and optimized using Quality by Design (QbD) concept. Based upon the quality target product profile (QTPP), critical quality attributes (CQAs) and critical material attributes (CMAs) were finalized. D-optimal mixture design was employed to find the points of the CMAs in the design space. Globule size and percentage cumulative drug release were set as CQAs. The nanoemulsion was gellified and the obtained nanoemulgel was further assessed for physical and skin permeation characteristics. From the permeation study it was found that the nanoemulgel showed better skin permeation and skin retention features of Silymarin in contrast to its conventional gel. Further, the outcome of Confocal Laser Scanning Microscopy (CLSM) advocated the efficiency of nanoemulgel as Rhodamine B was highly spotted in the deeper skin layers. Hence, the developed Silymarin loaded nanoemulgel proved to be a promising topical delivery system for improved antiphotoageing activity.