Multifunction hexagonal liquid-crystal containing modified surface TiO₂ nanoparticles and terpinen-4-ol for controlled release

Figures & data

Table 1 Composition of the liquid-crystalline formulations and release constants (K₀p and K₀q) for formulations F1 and F5 (data are mean ± SEM, n=6)

Sample notation	F1	F5
PC (% w/w)	48	48
IP (% w/w)	29	25
H2O (% w/w)	22	22
TiO2 added to the formulations (% w/w)	30	30
TP (% w/w)	1	5
Release constant K0p [% (μg) h^−1]	1.12±0.07	1.0±0.10
Release constant K0q (μg cm^−2 h^−1)	20.8±0.71	97.3±1.59

Abbreviations: h, hours; IP, isopropyl palmitate; PC, PPG-5 Ceteth 20; SEM, standard error of the mean; TP, terpinen-4-ol; w, weight.

Figure 1 TEM image of TiO₂ nanoparticles obtained by sol-gel process.

Abbreviations: TEM, transmission electron microscopy; TiO₂, titanium dioxide.

Figure 2 Visible diffuse reflectance spectra of liquid-crystalline formulations containing 15% commercial TiO₂ and 30% PTSH-modified TiO₂ nanoparticles.

Abbreviations: PTSH, p-toluene sulfonic acid; TiO₂, titanium dioxide.

Figure 3 Absorbance spectra of liquid-crystalline formulations with and without TiO₂ nanoparticles.

Notes: λ_c of the formulation containing TiO₂ is appointed over the arrow which traces 90% of the area under the spectrum from 290 to 400 nm.

Abbreviations: λ_c, critical wavelength; TiO₂, titanium dioxide.

Figure 4 SAXS curves and polarized light micrographs of liquid-crystalline formulations (A) F1 and F5 and (B) F1.

Note: *Appoints the peaks related to the hexagonal phase.

Abbreviations: I(q), scattering intensity; SAXS, small-angle X-ray scattering.

Figure 5 Terpinen-4-ol release profiles of F1 and F5 formulations.

Notes: (A) % (μg) plotted versus time comparing TP (1% and 5%) incorporated in propylene glycol and (B) Q terpinen-4-ol (μg/cm²) plotted versus time (data are mean ± SD, n=6). The lines on both graphs represent the zero-order regression line.

Abbreviations: h, hours; SD, standard deviation; TP, terpinen-4-ol.