2-Thiouracil Antithyroid Drug Delivery with Functionalized BC ₃ Monolayers: A First-Principles Study

2-Thiouracil (C₄H₄N₂OS), an antithyroid drug (ATD) used in the treatment of Graves' disease and thyroid storm, requires an effective drug delivery vehicle to successfully reach the thyroid gland. Using first-principles calculations, the adsorption of the 2-thiouracil molecule on pristine, Si-doped, and Al-doped BC₃ monolayers was studied based on density functional theory (DFT). Our results show that chemisorption of 2-thiouracil is stronger on Si-doped BC₃ than on Al-doped BC₃, while pristine BC₃ shows weak physisorption. On the doped monolayers, the O atom on 2-thiouracil displayed bond formation, hybridization, and stronger adsorption to the dopants compared to the S atom. We concluded that, of the 10 configurations computed, 2T-O_h/Si-BC₃ had the largest adsorption energy, making it the most promising configuration for future antithyroid drug delivery research. Our findings highlight how doped BC₃ monolayers can act as effective drug delivery platforms for the antithyroid drug, potentially improving the treatment of Graves' disease with future experimental validation.