Insulin fast-dissolving film for intranasal delivery via olfactory region, a promising approach for the treatment of anosmia in COVID-19 patients: Design, in-vitro characterization and clinical evaluation

The present work aimed to formulate intranasal insulin fast-dissolving films for treatment of anosmia in patients post COVID-19 infection. Variant films were prepared employing the casting method and using hydroxypropyl methyl cellulose and polyvinyl alcohol. The formulated films were investigated for insulin content, weight variation, surface pH, thickness, folding endurance and disintegration time. In vitro release study was conducted for the selected formulations (F6, F7, F8). A drug/polymer interaction was investigated in the optimized formulation (F7) employing Fourier transform infrared spectroscopy. Clinical study was accomplished for F7 on 20 patients. Sniffin’s and olfactory discrimination tests were used for assessing patients. The formulated films displayed appropriate physical characteristics. F7 showed the shortest disintegration time (50 ± 7 s) and fastest release. It displayed compatibility between the drug and the used polymers. The results of the clinical study revealed a significant increase in the olfactory detection scores and olfactory discrimination values in the intervention group (7.9 ± 1.2, 6.7 ± 0.5 respectively) compared to placebo group (3 ± 0.8, 2.8 ± 1).. Intervention group showed significant differences between these scores before and after treatment while the placebo group did not display any significant differences. Thus, the optimized film can be considered as an auspicious approach for managing post COVID-19 anosmia.