New Green and High-throughput Microwell Spectrophotometric Method for Quality Control of Pharmaceutical Formulations of Selective Serotonin Reuptake Inhibitors via Microscale Formation of their N-Vinylaminonaphthoquinone Derivatives

Background: Selective serotonin reuptake inhibitors (SSRIs) are mostly prescribed for the treatment of depression. This study describes the microscale in-microwell formation of blue-colored N-vinylamino-naphthoquinone derivatives of SSRIs upon their reaction with 2,3-dichloro-1,4- naphthoquinone (DCNQ) and acetaldehyde. The reaction was subsequently utilized as a basis for the development of a new simple and sensitive microwell spectrophotometric method (MW-SPM) for the quality control of pharmaceutical formulations of four SSRIs. These SSRIs are fluoxetine (FLU), sertraline (SER), paroxetine (PAR), and reboxetine (REB). Methods: The MW-SPM procedure was performed in 96-microwell transparent plates, and the microplate reader was employed to measure the absorbances of the reaction products at their peak absorbance wavelength of 580 nm. The best conditions for the method were determined. Results: The relations showed good linearity (correlation coefficients were ≥0.9992) in the concentration range of 5 – 600 µg/mL. The limits of detection ranged from 5.20 to 15.58 µg/mL. The precision was deemed acceptable since all cases' relative standard deviation (RSD) values remained below 2.21%. Recovery experiments were conducted to confirm the accuracy of the method, yielding recovery values of at least 97.8%. The MW-SPM method was effectively utilized to analyze SSRIs in both their bulk and pharmaceutical dosage forms, exhibiting acceptable accuracy and precision. The recovery values ranged from 99.4% to 101.0% (with a margin of error of ± 0.5% to 1.6%). The results were comparable with those of the pre-validated reported methods. Four different metric tools evaluated the greenness of the proposed method, and the results proved that the method fulfills the requirements of green analytical approaches. Furthermore, the ability to handle numerous microvolume samples simultaneously in the described method provides it with a high-throughput characteristic. Conclusion: The proposed MW-SPM represents a valuable tool for an efficient analysis of SSRIs in pharmaceutical quality control units.