Eutectic-based self-emulsifying drug delivery system for enhanced oral delivery of risperidone

Implementing therapeutic deep eutectic systems (THDESs) in various drug delivery systems (DDSs) has expanded enormously. THDESs offer eco-friendly alternatives to conventional organic solvents, featuring adaptable and simple preparation methods with high-yield products. Previously, the solubility of risperidone (RISP) was immensely enhanced by forming a hydrophobic THDES of RISP with capric acid (CA). To build upon the previous findings and utilize the hydrophobic properties of THDES, a self-emulsifying drug delivery system (SEDDS) was developed. A stable SEDDS formulation was successfully developed using the THDES as the nonpolar phase, a nonionic surfactant, Tween 20, and a co-surfactant, PEG 400. By employing a pseudo-ternary phase diagram, the ideal ratio of Tween 20 to PEG 400 was determined to be 3:1. The developed SEDDS demonstrated robust stability in thermal stability tests, dispersity evaluations, and dilution tests, exhibiting no instances of phase separation or precipitation. Gratifyingly, the <i>in vitro</i> dissolution of RISP through the developed SEDDS showed a higher release by 3-fold after 5 min and achieved 90% release within 2 hours. More interestingly, the plasma profile of RISP and the SEDDS were compared in rats, which revealed an improved drug bioavailability, as indicated by the attained higher AUC0–∞ (3907.06 versus 3426.28 h µg/ml) and a significantly higher Cmax (68.97 versus 50.35 µg/ml) with the SEDDS formulation when compared to RISP.