## 3 Results
### Hydrogels Reduce the Permeation of Sodium Flourescein and Rhinovirus 14  
Figure 4 shows the cumulative diffusion of sodium fluorescein across mixed cellulose ester membranes covered with three different hydrogel complex concentrations (isla Conc. 1-3) or artificial saliva. The diffusion was tracked for six hours. All hydrogel complexes, obtained by dissolving isla(r) medic in different volumes of artificial saliva, result in a reduction of sodium fluorescein diffusion. Since the incubation period with the  
Figure 4: Cumulative diffusion of 20 ug sodium fluorescein across a mixed cellulose ester membrane covered with hydrogel samples or artificial saliva (300 \(\mu\)L) over 6 h, \(\bullet\) artificial saliva, \(\blacklozenge\) 0.23 g lozenge/mL, \(\blacktriangle\) 0.115 g lozenge/mL, and \(\times\) 0.077 g lozenge/mL. Mean \(\pm\) standard deviation. Each sample was measured in triplicate. Figure 3: Viscosity of artificial saliva, 0.35% xanthan gum, and 0.65% sodium hyalurone at a shear rate range of 1–100 s\({}^{-1}\) and 33 \({}^{\circ}\)C (19 data points, linear ramp), \(\bullet\) artificial saliva, \(\vartriangle\) 0.35% xanthan gum, \(-\) 0.65% sodium hyalurone. Mean \(\pm\) standard deviation. Each sample was measured in triplicate. hydrogen complexes and the virus in the preventive plaque assay is 60 minutes, the diffusion of sodium fluorescein at 60 min will be compared in the following. After 60 minutes, \(11.9\pm 0.5\)\(\upmu\)g sodium fluorescein can be detected in the acceptor medium of the diffusion cells loaded with artificial saliva. In contrast, a total of \(2.5\pm 0.5\)\(\upmu\)g of the 20-\(\upmu\)g sodium fluorescein applied diffuses through isla Conc. 1 (0.23 g lozenge/mL). The reduction in sodium fluorescein diffusion depends on the concentration of the hydrogel complex of \(3.4\pm 0.5\)\(\upmu\)g (0.115 g lozenge/mL, isla Conc. 2) and \(6.5\pm 0.7\)\(\upmu\)g (0.077 g lozenge/mL, isla Conc. 3). In relation to the untreated control, isla Conc. 1 reduces the sodium fluorescein diffusion at 60 min by \(78.9\pm 4.1\%\) (isla Conc. 2 \(71.8\pm 3.8\%\), isla Conc. 3 \(45.5\pm 5.8\%\)). Figure 5 shows the cumulative diffusion of sodium fluorescein across mixed cellulose ester membranes covered with 0.35% xanthan gum and 0.65% sodium hyaluronate in artificial saliva. The diffusion of sodium fluorescein is also reduced by these two hydrogels. In 60 minutes, \(5.7\pm 0.4\)\(\upmu\)g of sodium fluorescein diffuses through 0.35% xanthan gum and \(3.8\pm 0.6\)\(\upmu\)g through 0.65% sodium hyaluronate. This results in a reduction of \(52.4\%\pm 3.3\%\) for xanthan gum and \(68.3\%\pm 5.1\%\) for sodium hyaluronate. Permeation studies were conducted with RV-14 to investigate whether the inhibition of diffusion caused by the hydrogels also works for rhinoviruses. The amount of virus in the acceptor medium was quantified by determining the virus titer as TCID\({}_{50}\)/0.2 mL. Higher virus titers can be detected in the virus solutions permeated through the hydrogels, which indicates that the virus concentration in the acceptor medium is lower than the control without a hydrogel, \(10^{4.59}\pm 10^{0.36}\) TCID\({}_{50}\)/0.2 mL (control), \(10^{2.44}\pm 10^{0.03}\) TCID\({}_{50}\)/0.2 mL (0.23 g lozenge/mL, isla Conc. 1), \(10^{3.42}\pm 10^{0.06}\) TCID\({}_{50}\)/0.2 mL (0.115 g lozenge/mL isla Conc. 2), and \(10^{3.44}\pm 10^{0.04}\) TCID\({}_{50}\)/0.2 mL (0.077 g lozenge/mL, isla Conc. 3). With regard to the untreated control, a titer reduction with isla Conc. 1 (99% \(\pm\) 0.5%), isla Conc. 2 (92% \(\pm\) 5%), and isla Conc. 3 (91% \(\pm\) 5%) was conducted. Hydrogels Reduce Rhinovirus Infections In vitro and Have a Curative Effect on Infected H1-HeLa Cells  
First, the influence of the hydrogel complexes (isla(r) medic Conc. 1-3) and the hydrogels based on xanthan gum or sodium hyaluronate on H1-HeLa cell viability was examined over 2 h to determine which concentrations are suitable for the in vitro experiments.