Simultaneous Estimation of Lesinurad and Allopurinol in the New FDA-Approved Products Using a Greener Normal-Phase HPTLC Method: Greenness Assessment Using the NEMI, Analytical Eco-Score, ChlorTox, and AGREE Methods

Recently, the U.S. Food and Drug Administration (FDA) approved combined dosage forms of lesinurad (LND) and allopurinol (ALU) in fixed-dose combinations to treat hyperuricemia associated with gout. For the simultaneous estimation (SME) of LND and ALU, neither conventional "high-performance thin-layer chromatography (HPTLC)" nor a greener HPTLC approach has been published to date. This study was carried out to design and validate a rapid, sensitive, and greener normal-phase HPTLC technique for the SME of LND and ALU in FDA-approved fixed-dose combination tablets. Ethyl acetate, ethanol, and water in a ternary ratio of 70:20:10 (v/v/v) were employed as a greener eluent system for the SME of LND and ALU. Normal-phase silica gel 60F254S plates were employed as the stationary phase. At a wavelength of 240 nm, LND and ALU were simultaneously estimated. The current method's greenness was assessed using the National Environmental Method Index (NEMI), Analytical Eco-Scale (AES), ChlorTox, and Analytical GREENness (AGREE) methodologies. The current method was linear in the 30-1200 ng/band range for LND and ALU. The current approach was extensively validated and demonstrated to be accurate, precise, robust, sensitive, and greener for the SME of LND and ALU. The results of all greenness tools, including NEMI, AES (89), ChlorTox (0.96 g), and AGREE (0.81) showed that the current approach had an exceptional greener profile. Using the present methodology, the amounts of LND in FDA-approved fixed-dose combinations A and B were measured to be 98.73 and 99.17%, respectively. Using the present methodology, the amounts of ALU in FDA-approved fixed-dose combinations A and B were determined to be 99.27 and 100.58%, respectively. These data support the applicability of the current methodology for SME of LND and ALU in FDA-approved products. The findings of this study suggested that the current approach may be consistently applied to measure the LND and ALU in FDA-approved products.