Turbisoft software

The mean size, size distribution, and z-potential were evaluated by a Zetasizer Nano ZS (Malvern Instruments Ltd., Worchestershire, United Kingdom), following a 1:50 dilution of the samples. Zetasizer Nano is a dynamic light-scattering spectrophotometer (DLS) and a third-order cumulant fitting correlation function was used for sample analysis. This instrument was equipped with a 4.5 mW laser diode operating at 670 nm, which was the light source; the back-scattered photons were detected at 173°. Before starting the analyses, the medium refractive index (1.330), medium viscosity (1.0 mPa × s), and dielectric constant (80.4) were set. The samples were placed in quartz cuvettes to be analyzed [26 (link)].
To evaluate the stability of the prepared vesicular carriers, Turbiscan Lab^® Expert, equipped with a Turbiscan Lab Cooler, was used. The photon transmitted (T) and backscattered (BS) through the samples, placed in a cylindrical glass tube, was detected [27 (link)]. The kinetic stability of the samples was evaluated from the data, obtained by TurbiSoft software (Formulaction, L’Union, France). Measurements were taken for 1 h at room temperature (24 ± 1 °C).

Mean size, size distribution and z-potential were evaluated using a Zetasizer Nano ZS (Malvern Instruments Ltd., Worchestershire, UK), which is a dynamic light-scattering spectrophotometer [46 (link)]. A third-order cumulant fitting was applied as a correlation function. The instrument used a 4.5 mW laser diode operating at 670 nm for size analysis and back-scattered photons were detected at 173°. The medium refractive index (1.330), medium viscosity (1.0 mPa × s), and dielectric constant (80.4) were set before the experiments. Polycarbonate cuvettes were used for the analysis.
The stability of the carriers was determined by using a Turbiscan Lab^® Expert [25 (link)], equipped with a Turbiscan Lab Cooler. Briefly, the samples were placed into a cylindrical glass tube and measurements were carried out for 1 h. The photon which was transmitted (T) and backscattered (BS) was recorded. Analysis was carried out at the temperature of 24 ± 1 °C. The analyses were performed using the TurbiSoft software (Formulaction, L’Union, France) and the obtained data were used to evaluate the kinetic stability of the formulations.

A long-term stability study over time of both empty and drug-loaded precursor solutions was performed using a Turbiscan^® Lab Expert apparatus equipped with a Turbiscan Lab Cooler. Each precursor solution was gently placed in a cylindrical glass tube and sealed with a suitable plug. Before starting the analysis, the sample was placed into the instrument vial slot, where it was left to equilibrate at 37 ± 0.5 °C (operative temperature) for five minutes. The measurements were conducted for 3 h, during which time the integrated TurbiSoft software (Formulaction, L’Union, France) recorded alterations in delta-backscattering (ΔBS) and delta-transmission (ΔT) profiles as a function of time and vial height [48 (link)], ultimately determining the destabilization kinetic profile by measuring the Turbiscan stability index (TSI). TSI values were directly derived from a sophisticated formula by the software according to Equation (3), as previously reported [49 (link)]: $$\mathrm{TSI}={\displaystyle \sum }_{\mathrm{i}}\frac{{\sum }_{\mathrm{h}}\left|{\mathrm{scan}}_{\mathrm{i}}\left(\mathrm{h}\right)-{\mathrm{scan}}_{\mathrm{i}-1}\left(\mathrm{h}\right)\right|}{\mathrm{H}}$$
where scan_i(h) is the average of backscattering recorded at each time (i) of measurement, scan_i−1(h) is the average of backscattering for the i−1 time of measurement and H represents the sample height. The stability of samples was compared in terms of TSI, considering that TSI values can change from 0 for highly stable systems to 100 for highly unstable compounds [50 ,51 (link)].