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Inhalation April 2024 13 range for nasal sprays of 85 to 115% [12]. Deposi- tion on the filter was below the limit of quantifica- tion for all runs, indicating a low risk of pulmonary deposition; also deposition in the olfactory and naso- pharynx regions was found to be minimal. Some variability was observed in the deposition data, which was attributed to device-to-device variability and slight differences in device alignment. Overall, how- ever, the results encourage further study and illustrate the value of the AINI to screen and optimize formu- lations for intranasal vaccination. Study 3. Assessing the potential for pulmonary deposition A study by Potts, et al. illustrates use of the AINI to investigate the potential for pulmonary deposition and provides evidence of the potential merits of using a more physiologically representative test set-up, rela- tive to laser diffraction particle sizing, to assess this risk [18]. ree spray-dried formulations of caffeine were prepared then delivered into a test set-up consisting of an AINI attached to an NGI; an Aptar Unidose device (Aptar Pharma, Louveciennes, France) was used for dose delivery. Formulations 1 and 2 were prepared from a 69:30:1 (%w/w/w) hydroxypropyl methylcel- lulose (HPMC), mannitol, caffeine solution; Formu- lation 3 was prepared from a 95:5 (%w/w) trehalose, caffeine solution. Tests were carried out using a test flow rate of 7.5 L/min, a spray orientation angle of 45 o and an insertion depth of 1 cm. icant difference observed in each data set, with the exception of the very low throat deposition measure- ment observed for Nasonex. However, this throat deposition is too low to be judged clinically signifi- cant. Administration angle has an observable effect on deposition behavior but for QNASL, which has a device form that defines spray orientation to a greater extent than either of the other two products, a 60 o angle may not be representative of typical use. e over-prediction of deposition in the nose asso- ciated with this test condition may therefore be of limited clinical relevance. ese three topical sprays/aerosols vary considerably in terms of deposition behavior with the fraction of the dose delivered to the mid- and upper nasal region being higher with NasalCrom than with the QNASL aerosol which, in contrast, focuses drug delivery into the anterior section of the nose. e study therefore usefully demonstrates the potential to use the AINI to differentiate nasal drug products for targeted systemic action. Study 2. Assessing the potential for intranasal delivery of an Entamoeba histolytica vaccine In work by Murphy, et al., the AINI was used in an in vitro study of the feasibility of delivering an Enta moeba histolytica vaccine candidate intranasally using a syringe-based liquid atomization device [17]. e vaccine candidate combines a recombinant soluble protein antigen with a liposomal adjuvant formula- tion and had been previously optimized with respect to immunogenic response and stability. e syringe device is filled and actuated at the point of use and could therefore offer a low-cost, easy-to-use solution for widespread vaccination. During testing, the AINI was orientated to simu- late administration to a seated upright patient, with a breathing filter attached to collect residual drug penetrating through the outlet. e nasal device was actuated automatically using actuation parameters determined via ergonomic testing, with five trained individuals. Testing was carried out at a flow rate of 7.5 +/- 0.1 L/min, at an orientation angle of 45 o , with two 100-µL doses delivered for each test, each actuated from a separate, new delivery device; six replicate tests were carried out. Deposition profiles were determined by an ELISA of the formulation lost from the nasal inlet by dripping (drops were captured with a cotton swab), deposited in different regions of the AINI and on the filter. e data generated indicated high levels of deposition in the turbinates, a highly vascularized, lymphoid tis- sue-rich area routinely targeted for intranasal vaccine delivery. e data also demonstrated high recovery of the active pharmaceutical ingredient (API) (mass balance total ~90%), within the FDA-recommended