Fig. 4.

¹¹¹In-Alginate shows enhanced retention in the nose compared to a control solution of ¹¹¹In-EDTA. Maximum intensity projection SPECT-CT image timecourse showing retention of a.¹¹¹In-Alginate and b.¹¹¹In-EDTA after nasal administration. c. A significantly higher % ID is retained in the nose in the alginate group compared to control up to 4 days (n = 3; 2-tailed T-test; *p < 0.01, **p < 0.001). d. A higher % of the injected dose is present in the abdomen in the control group, showing gut clearance, at 90 min after dosing (0 days), vs the alginate group (n = 3; 2-tailed T-test; *p < 0.05). Error bars show SEM. e. Axial T₁-weighted magnetic resonance image showing signal hyper-intensity in the olfactory bulb after nose-to-brain delivery of Mn²⁺ from alginate, but not in the control condition before dosing. f. Coronal section and dorsal maximum intensity projection SPECT-CT images showing signal in the basal ganglia following nasal delivery of ¹²³I-DatScan in 0.6% alginate, confirming nose-to-brain delivery to pre-synaptic dopamine transporters within 2 h of dosing.