Design of self-microemulsifying drug delivery systems using a high-throughput formulation screening system

Purpose: A high-throughput formulation screening (HTFS) system that enabled to rapidly and efficiently select self-microemulsifying drug delivery system (SMEDDS) formulations has been developed in our previous study. The purpose of this study was to investigate the applicability of the HTFS system to SMEDDS designs. Methods: A poorly soluble drug (Nilvadipine), an oil (Sefsol-218), 11 hydrophilic surfactants (HS), and 10 lipophilic surfactants (LS) were used. Formulations were prepared and SMEDDS formulations were chosen by the HTFS system. A HS with the largest number of SMEDDS formulations was selected. In the selected HS system, a LS with the largest number of SMEDDS formulations was selected. Formulations with minimum turbidity at each ratio of the selected HS LS were chosen as optimized formulations. Results: A total of 2455 formulations were prepared and SMEDDS formulations were selected using the HTFS system. From the screening data, HCO60 was selected as a superior emulsifiable HS, and Plurol (PLUROL OLEIQUE CC497) was selected as a suitable LS to HCO60. Five optimized formulations were chosen from the HCO60 Plurol system. The formulations formed fine microemulsions (