Improving dissolution and photostability of resveratrol using redispersible dry emulsion: Application of design space for optimizing formulation and spray-drying process

A redispersible dry emulsion (DE) containing resveratrol (RVT) was developed using low-methoxy pectin (LMP) and caprylic/capric glyceride (CCG) as the emulsifier and component comprising the lipid phase, respectively. The effects of formulation and the pump speed of spray dryer on the resultant redispersed emulsion size, angle of repose, and spraying efficiency were investigated and optimized using the Box-Behnken design. Redispersibility was used to estimate dissolution properties of RVT-DE. Experimental results showed that the size of the redispersed emulsion was affected by LMP and CCG concentrations. An increase and decrease in LMP and CCG concentrations, respectively, resulted in smaller emulsion droplet size and more rapid drug dissolution from RVT-DE. The angle of repose in RVT-DE was also influenced by LMP and CCG concentrations. RVT-DE generated using low LMP concertation and high CCG concentration showed a low angle of repose, indicating good flow property. An optimized formulation containing 2.75% w/w of LMP and 7% w/w of CCG sprayed at a pump speed of 10.1 mL/min prepared within design space satisfied all criteria i.e. small redispersed size, good flow, and high spraying efficiency. The photostability of RVT in RVT-DE was significantly higher than that in intact RVT.