Development and Validation of an UPLC-MS/MS Method for Remodelin Quantification in Mouse Plasma and Tissues: Application to Biodistribution and Ultrastructural Assessment.

Remodelin, a selective N-acetyltransferase 10 (NAT10) inhibitor, has emerged as a promising therapeutic candidate for degenerative diseases with nuclear abnormalities and acetylation dysregulation. However, its pharmacological development has been hindered by the lack of a sufficiently sensitive bioanalytical method. To address this limitation, a simple, sensitive, and reliable ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) method was established and fully validated. This method achieved accurate quantification of remodelin at low pg/mL levels, representing a significant improvement in sensitivity and excellent linearity (R 2 > 0.99). All validation parameters met the predefined bioanalytical acceptance criteria. This method was applied to quantify remodelin in C57BL/6J mouse plasma and various tissues (carotid artery, heart, liver, and kidney), with higher concentrations observed in the liver and kidney. Given the proposed role of remodelin in maintaining nuclear integrity, its protective effect was further investigated by transmission electron microscopy (TEM). The analysis provided direct evidence of a protective effect on nuclear morphology, with treated tissues maintaining intact nuclear membranes and clear cellular architecture, whereas untreated tissues exhibited varying degrees of structural damage. These findings established a robust analytical method for remodelin quantification and provided preliminary ultrastructural evidence of its protective effects, supporting further pharmacodynamic investigation.