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 in vitro 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.