Molecular Encapsulation of Herbicide Terbuthylazine in Native and Modifiedβ-Cyclodextrin

Abstract

The herbicide terbuthylazine (TBA) is widely used for preemergence or postemergence control of many grass and broadleaf weeds and has, besides other issues, a poor aqueous solubility profile that results in reduced bioavailability. Cyclodextrins and modified cyclodextrins were considered, among other substances, appropriate agents for improving pesticide water solubility. Therefore, the inclusion complex formation of terbuthylazine with -cyclodextrin ( -CD) and hydroxypropyl--cyclodextrin (HP--CD) was studied to attain its aqueous solubility enhancement. Their characterization was accomplished with different analytical techniques, namely, by UV-Vis, DSC, FTIR, and 1 H NMR. From the analysis of the complexation performance of the herbicide it was concluded that the interaction of terbuthylazine with CDs leads to the formation of inclusion complexes with a stoichiometry of 1 : 1. The association constants of the TBA/ -CD and TBA/HP--CD complexes were determined by UV. The mean values obtained for the stability constants are 460.4 ± 26.5 and 532.1 ± 27.6 to TBA/ -CD and TBA/HP--CD, respectively.1 H NMR data corroborate the formation of the TBA/ -CD and TBA/HP--CD complexes synthesized by the kneading method. A formulation incorporating TBA cyclodextrin complexes might lead to an improvement in terbuthylazine bioavailability. The development of TBA-CD formulations may be interesting since it would enable, through their inclusion into the hydrophobic cavity of CDs, enhancement of solubility, bioavailability, and stability of the herbicide.

Reduction of soil contamination by cypermethrin residues using phytoremediation with Plantago major and some surfactants

“…Moreover, the addition of HPβCD increased PCB bioavailability leading to enhanced PCB removal and plant uptake [81]. Furthermore, HPβCD can contribute to an improvement in the effectiveness of terbuthylazine in terms of its bioavailability in soil [82]. Fluorene and fluoranthene were removed from contaminated soils by HPβCD [83].…”

Pulsatile Chronotherapeutic Drug Delivery for Controlling Early Morning Surge in Blood Pressure; Effect of Coating on Eplerenone In-vitro, In-vivo Release and Urinary Na/K Ratio

“…Ep release from core tablets (Figure 4) showed over 80% drug release within the first 10 minutes since complexation with β-CD greatly improved Ep dissolution as compared to pure Ep (Figure 4) due to increased solubility and rapid wettability of the complexed drug. β-CD exhibits a hydrophilic exterior with a hydrophobic internal cavity where the guest molecule could fit into, thus increasing its affinity toward water and increasing the dissolution (Garrido et al, 2017).…”

Polymeric Systems for the Delivery of Herbicides to Improve Weed Control Efficiency

“…Cyclodextrin has a unique structure, which enables it to form inclusion complex with hydrophobic active molecules. Terbuthylazine herbicide molecule was encapsulated using cyclodextrin, which showed improved solubility and bioavailability of herbicide molecule [119].…”