An Integrated experimental and computational study of the interaction between triamcinolone acetonide(TA) and human growth hormone(hGH) using UV/Vis spectroscopy and Molecular Docking

Abstract

The interaction between triamcinolone acetonide (TA) and human growth hormone (hGH) was investigated using UV–Vis spectrophotometry under optimized experimental conditions. TA exhibited a maximum absorbance at 342 nm and followed the Beer–Lambert law in the concentration range of 2.3 × 10⁻⁴ to 4.5 × 10⁻⁴ M, indicating monomeric behavior in solution. Upon addition of hGH, a decrease in absorbance and the presence of an isosbestic point confirmed complex formation between TA and hGH. The interaction was found to be strongly pH-dependent, with maximum binding occurring at pH 2, while ionic strength showed negligible influence, suggesting an ion–dipole interaction mechanism. Binding stoichiometry was determined to be approximately 1:3 (hGH:TA). Thermodynamic parameters obtained from Van’t Hoff analysis revealed negative values of ΔG°, ΔH°, and ΔS°, indicating a spontaneous, exothermic, and entropy-unfavorable process. Temperature-dependent studies showed reduced binding affinity at higher temperatures, consistent with an exothermic interaction. Overall, the results demonstrate a weak but spontaneous interaction between TA and hGH, supporting the inhibitory role of TA on growth hormone activity and highlighting UV–Vis spectroscopy as a simple and reliable method for biomolecular interaction studies.