Selective Extraction and Determination of Hydrocortisone and Dexamethasone in Skincare Cosmetics: Analytical Interpretation Using Statistical Physics Formalism

: Molecularly imprinted polymers (MIPs), as magnetic extraction adsorbents, are used for
the selective, rapid determination and extraction of dexamethasone and hydrocortisone in skincare
products. Therefore, in this paper, magnetic molecularly imprinted polymers (MMIPs) and magnetic
non-molecularly imprinted polymers (MNIPs) were utilized as adsorbents to describe the adsorp
tion phenomena of dexamethasone and hydrocortisone. This interpretation, based on a statistical
physics theory, applies the multilayer model with saturation to comprehend the adsorption of the
drugs. Results obtained via numerical simulation revealed that dexamethasone and hydrocortisone
adsorption happens via a non-parallel orientation on the surfaces of MMIPs and MNIPs, and they
also showed that the adsorption amount of the MMIPs for the template molecule was notably greater han that of the MNIPs at the same initial concentration. The adsorption energy values retrieved
from the data analysis ranged between 7.65 and 15.77 kJ/mol, indicating that the extraction and
determination of dexamethasone and hydrocortisone is a physisorption process. Moreover, the distri
bution of a site’s energy was calculated to confirm the physical nature of the interactions between
adsorbate/adsorbent and the heterogeneity of the surfaces of the MMIPs and MNIPs. Finally, the
thermodynamic interpretation confirmed the exothermicity and spontaneous nature of the adsorption
of these drugs on the tested adsorbent