Fernandes, Sara R.Fernandes, SaraChaves, Luíse L.Lima, Sofia A. C.Silva, Eduarda M. P.Barreiros, LuísaReis, SaletteSegundo, Marcela A.2025-07-082025-07-082018-03Machado, S., Fernandes, S. R., Chaves, L. L., Lima, S. A. C., Silva, E. M. P., Barreiros, L., Reis, S., & Segundo, M. A. (2018). Simultaneous determination of dapsone and clofazimine in nanoformulations by HPLC. Book of Abstracts Analítica 2018 - 9th Meeting of Division of Analytical Chemistry, 85. https://analitica2018.eventos.chemistry.pt/images/book.pdf978-989-8124-21-0http://hdl.handle.net/10400.22/30214The multidrug therapy with dapsone (DAP) and clofazimine (CLZ) is known as an effective treatment against Mycobacterium leprae. However, the low bioavailability and non-specific distribution can reduce therapy efficacy and produce side effects. The use of nanotechnological approaches was explored as a promising carrier for delivery enhancement of these drugs. Therefore, a simple and precise highperformance liquid chromatography (HPLC) method with UV/Vis detection has been developed and validated for the simultaneous determination of DAP and CLZ loaded in solid dispersion and poly(D,L-lactide-co-glycolic acid) nanoparticles, respectively, targeting therapy improvement. A reversed phase Kinetex core-shell C18 column at room temperature followed by UV/Vis detection at 280 nm was used for chromatographic separation. The elution was performed in gradient mode using aqueous acetate buffer (50 mol L-1, pH 4.8) and an increasing acetonitrile content from 27 to 63% (v/v), at a flow rate of 1.0 mL min-1. The injection volume was fixed at 20 µL and total run time was 23.0 min, with a retention time of 6.0 min for DAP and 14.0 min for CLZ. The method was validated according to EMA guideline and showed specificity, accuracy (between 99.6 and 114.0% of nominal values) and precision for intra-day (RSD ≤1.8%) and inter-day assays (RSD ≤12.5%). Calibration curves were linear (r2 >0.9979) and LOD ≤0.03 and LOQ ≤0.06 mg L-1 were obtained. Stability was studied after 24 h at room temperature and over three freeze-thaw cycles, and recovery values ≥86.2% were obtained. Precipitation of CLZ was observed at low temperatures (4 °C). Entrapment efficiency in nanoformulations was evaluated as 54.8 ± 0.1% for DAP and 24.9 ± 0.2% for CLZ. The developed method was successfully validated for the simultaneous determination of DAP and CLZ in nanoparticles.engDapsone (DAP)Clofazimine (CLZ)conference poster