Design and optimization of resveratrol-loaded porous calcium silicate powders for dissolution and photostability enhancement

In this study, resveratrol (RVT) was loaded onto porous calcium silicate (PCS) powders to improve its dissolution and photostability properties. The effects of RVT/PCS powders that included varying amounts of low-methoxyl pectin (LMP), ethyl acetate (EA) and PCS on drug loading capacity, encapsulation efficiency and drug dissolution at 5-min intervals (Q(5)) were investigated using a Box-Behnken design. The experimental results demonstrated that the EA and PCS amounts significantly influenced drug loading capacity. Encapsulation efficiency was affected by EA amount, whereas the amount of PCS had a significant effect on Q5. Empirical experiments demonstrated the reliability of mathematical models. A design space was established based on the criteria set for maximizing each response of the RVT/PCS powders. An optimized formulation containing 2.6% w/w LMP, 19% w/w EA and 13% w/w PCS prepared within the design space satisfied all criteria. The dissolution and photostability of RVT in the RVT/PCS powders were significantly improved. Further, the bulk density of the PCS powders in RVT/PCS was increased by LMP. The Box-Behnken design used in this study provided an improved understanding of the effects of formulation factors on RVT/PCS powder characteristics as well as the optimization of RVT/PCS powder formulations with the desired properties.