Ultrasound-Assisted DLLME Coupled with TLC Imaging for Rapid Determination of Risperidone in Biological Samples

Risperidone (RSP) is an antipsychotic drug widely prescribed for patients suffering from depression or other psychotic episodes. However, its misuse or overdose has been implicated in accidental and suicidal fatalities, underscoring the need for sensitive and reliable analytical methodologies for its determination in biological samples. In the present study, the ultrasonic-assisted dispersive liquid–liquid microextraction (UA-DLLME) technique, coupled with thin-layer chromatography (TLC) and a smartphone-based digital image colorimetry analytical method, was developed, optimized, validated, and applied for the determination of RSP in blood, urine, and pharmaceutical samples. Among the tested conditions, trichloroethylene (100 µL) and acetonitrile (800 µL) were found to be the most suitable extraction and dispersing solvents, respectively, at a pH of 10, with 1 minute of ultrasonication yielding the maximum extraction efficiency. An ethyl acetate:methanol:ammonia solution (85:10:5 v/v/v) was used as the mobile phase to achieve TLC separation. Calibration curves exhibited linearity in the concentration range of 0.25–10 mg/mL with limits of detection (LOD) of 0.18, 0.22, and 0.03 mg/mL and limits of quantification (LOQ) of 1.00, 0.08, and 0.46 mg/mL for blood, urine, and tablet samples, respectively. The accuracy and precision (intraday and interday) were also calculated according to SWGTOX guidelines. The recovery for the method was 165.03%, 81.88%, and 98.34% for blood, urine, and pharmaceutical tablet samples, respectively. In the next step, greenness of the method was identified using the complex Green Analytical Procedure Index (GAPI) and the Analytical Greenness (AGREE) calculators, and Environmental, Performance, and Practicality Index (EPPI), confirming its environmental sustainability. Developed an analytical method for UA-DLLME–TLC–smartphone colorimetry provides a rapid, cost-effective, environmentally sustainable strategy for the determination of risperidone in biological samples, with substantial applicability in forensic toxicology for the identification and quantification in suspected overdose or poisoning cases.