Hybrids of Layered Double Hydroxides and Sodium Dodecyl Sulfate: Structural Effects on the Controlled Release of Pretilachlor.

Organo-layered double hydroxides (OLDHs) are widely used as slow-release carriers for drugs but are rarely used in controlled drug release. To develop slow-release substrates of pretilachlor with excellent controlled release properties, OLDH hybrids were prepared by intercalating different masses of sodium dodecyl sulfate (SDS) into MgAl-LDHs. The underlying structural characteristics were analyzed by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), scanning electron microscopy (SEM), and contact angle measurements. Also, the adsorption capacity and release properties of OLDHs were explored by batch adsorption isotherms, adsorption kinetics, and release kinetics to reveal the structural effects of OLDHs on the release of pretilachlor. The results showed that the release of pretilachlor from OLDHs was dominated by Fickian diffusion and was closely related to the adsorption capacity and permeability of the matrix. The intercalation of SDS enhanced the hydrophobicity of LDHs, resulting in a higher adsorption capacity for pretilachlor and a lower permeability. Furthermore, as the SDS loading amount increased from 0.5 to 4.0 g, the adsorption capacity of the OLDHs was further enhanced ( value increased from 2.52 to 12.83), while the permeability ( / value) reversed, decreasing from 0.21 to 0.09. The release kinetics demonstrated that the release rate of pretilachlor from OLDHs was significantly lower compared to pure LDHs and showed a continuous decrease with increasing SDS loading amounts. The release time of 50% ( ) pretilachlor from OLDHs with SDS loading amounts of 25%, 50%, 100%, and 200% of the anion exchange capacity was 4.78, 8.28, 25.4, and 45.34 times longer than the release time from pure LDHs. This displayed a strong curvilinear relationship with the adsorption rate constant and permeability / and a good linear relationship with the added amount of SDS. These findings highlight the potential of OLDHs in preparing pretilachlor controlled release formulations.