Curcumin-Encapsulated Hexagonal Liquid Crystalline Formed by Brij 97/NaDC Mixtures

Abstract

The phase diagram of a five-components Brij 97-NaDC/IPM-PEG 400/H 2 O system was determined at 25 C. The hexagonal liquid crystalline phase (H 1 ) was found in this system. By use of small-angle x-ray scattering (SAXS), polarization microscopy, and rheology techniques, the influence of composition, temperature, and addition of curcumin on H 1 phase was studied. It is shown that: 1) the investigated hexagonal liquid crystals exhibit a strong shear thinning behavior and viscoelasticity and the strength of the network of H 1 phase becomes weaker with increasing oil content; 2) the frequency-dependent moduli of H 1 samples decreases as the 1699 temperature increases and the steady-state limiting viscosity of the hexagonal samples shows an Arrhenius-like dependence on temperature; and 3) samples in H 1 phase containing curcumin retained their organized hexagonal structure. The SAXS results show that the curcumin molecules may be solubilized both into the apolar core of cylinders together with IPM and in the polar domain coexisting with PEG 400 between the cylinders. When curcumin is encapsulated in samples with low oil content, there is a significant decrease in the frequency-dependent moduli. The tendency of frequency behavior for samples incorporating curcumin as a function of temperature is weakened.

Phase and Rheological Properties of a Curcumin‐Encapsulated Cubic Liquid Crystal

“…The pseudo-ternary phase diagram was determined in the same manner as in our previous work [13,14]. The ratio mentioned in this paper refers to the mass ratio.…”

“…In this work, the saturated solubility values of curcumin in IPM and PEG 400 were measured to be 0.38 mg/g and 97.86 mg/g, respectively, using a UV spectrometer (SP-2162 UV Spectrum, Shanghai Spectrum Instruments Co., Ltd., Shanghai, China) at a wavelength of 424 nm. The curcumin-saturated oil phases were prepared according to our previous report [13].…”

“…Measurements were carried out after 10 min to allow for stress relaxation. This method is the same as used in our previous work [13].…”

“…Our recent research [13] revealed that curcumin solubilized in different solvents had an effect on the microstructure and rheological properties of hexagonal liquid crystals. In this section, the effects of curcumin solubilized in different oil components on the properties of the cubic liquid crystals were investigated.…”

“…Rheological properties of hexagonal liquid crystals formed in mixtures of oleyl polyoxyethylene (10) ether (Brij 97) and sodium deoxycholate (NaDC) were investigated in our previous study [13], which indicated that hexagonal liquid crystals could be potential carriers for curcumin. Owing to the wide range of applications for cubic liquid crystals in drug delivery, the curcumin-encapsulated cubic liquid crystals formed in the Brij 97-NaDC/IPM-PEG 400/H 2 O system were investigated intensively by rheological measurements and small-angle X-ray scattering (SAXS) technique.…”