improvement of thymol properties by inclusion complex with β-cyclodextrin as the catalyst

Cyclodextrin (cd) is commonly used as a kind of water-soluble catalyst with high stability in water. cd ability to forman inclusion complex with the drug. this will change the physicochemical properties of the sample. formation of a drug/cd inclusion complex increase the aqueous solubility, increase its chemical and physical stability, and enhance drug delivery. thymol (2-isopropyl-5-methyl phenol) is a natural phenolic compound obtained from thyme essential oil, is one of the very effective antioxidant and antibacterial agents for microbial diseases. this feature of thymol can be widely used in the food and medical industry but its poor aqueous solubility and a strong bitter. in this research, we formed an inclusion complex of thymol/β-cyclodextrin as the catalyst increases the solubility rate without molecular modifications also, accelerate the in vivo thymol absorption rate compared with the a free thymol. this complex was prepared by freeze-drying (fd) methods. phase solubility studies were performed according to the method of higuchi and conners that stability constant was determined as k=14.7×102 m-1. the resultant complexes were characterized by fourier-transform infrared spectroscopy (ftir), x-ray diffraction (xrd), scanning electron microscopy (sem), and nuclear magnetic resonance (nmr).