Preparation, optimization using a mixture design, and characterization of a novel astaxanthin-loaded rice bran oil self-microemulsifying delivery system formulation

Abstract

This research aimed to develop a self-microemulsifying delivery system (SMEDS) to increase dissolution rate of astaxanthin (AST) using a design of experiment (DoE) approach for investigating the effect of components on the physicochemical properties of AST SMEDS formulation. By applying the mixture design, the optimal compositions of rice bran (RB) oil (oil; X₁), Kolliphor^® RH40 (surfactant; X₂), and Span^® 20 (cosurfactant; X₃) were determined based on the preliminary screening studies. The optimization models were validated by comparing the regression coefficient (R²) of the predicted values to the experimentally measured ones. Based on the desirability function, the optimized AST SMEDS was composed of 33.67% rice bran oil, 34.70% Kolliphor^® RH40, and 31.63% Span^® 20 which contained AST concentration (Y₁) of 0.04% in the formulation and yielded microemulsion droplet size (Y₂) of 40.79 ± 3.11 nm. The experimentally measured values obtained from the optimized AST SMEDS were in accordance with its predicted values with relatively low prediction errors (< 2%). The validated models were investigated by the contour plots, three-dimensional surface plots, and main effect plots. It was found that surfactant and cosurfactant inversely affected on droplet size changes whereas all three components (oil, surfactant and cosurfactant) did not relatively impact AST solubilizing capacity. In vitro release of AST SMEDS was significantly increased more than 90% compared to the raw AST powder. The optimized AST SMEDS was successfully developed by the mixture design and could be economically effective to enhance dissolution of poorly water-soluble AST.

Graphical Abstract

Keywords:

• Astaxanthin
• Self-microemulsifying delivery system
• Design of experiment approach
• Optimization
• Mixture design

Declaration of interest

The authors declare no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Acknowledgements

The authors gratefully appreciated the Grants for Development of New Faculty Staff, Ratchadaphiseksomphot Endowment Fund, Chulalongkorn University (Contract Number: DNS 62_008_33_001_1). The researchers would like to thank Professor Dr. Garnpimol C. Ritthidej, Ms. Mo Mo Ko Zin, scientific staffs, and technicians of the Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University for their laboratory assistance. The authors also wanted to thank the Pharmaceutical Research Instrument Center of the Faculty of Pharmaceutical Sciences and the Scientific and Technological Research Equipment Centre of Chulalongkorn University for providing research instruments. One of the authors (Ms. W.T. Aung) would like to acknowledge the Scholarship Program for ASEAN Countries granted from the Office of Academic Affairs, Chulalongkorn University for the financial support during her doctoral degree study. This thesis is supported by the Graduate School Thesis Grant, Chulalongkorn University (Grant ID: GCUGR1225643034D No. 034). This study was also financially supported by the Graduate Program of Pharmaceutical Sciences and Technology, Faculty of Pharmaceutical Sciences, Chulalongkorn University.

Funding 

Grants for Development of New Faculty Staff, Ratchadaphiseksomphot Endowment Fund, Chulalongkorn University (Grant ID: DNS 62_008_33_001_1); Graduate School Thesis Grant, Chulalongkorn University (Grant ID: GCUGR1225643034D No. 034); Research supporting grant from Graduate Program of Pharmaceutical Sciences and Technology, Faculty of Pharmaceutical Sciences, Chulalongkorn University.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.