Evaluation of patient experience for a computationally-guided intranasal spray protocol to augment therapeutic penetration

The global respiratory outbreak in the form of COVID-19 has underlined the necessity to devise more effective and reproducible intranasal drug delivery modalities, that would also be user-friendly for adoption compliance. In this study, we have collected evaluation feedback from a cohort of 13 healthy volunteers, who assessed two different nasal spray administration techniques, namely the vertical placement protocol (or, VP), wherein the nozzle is held vertically upright at a shallow insertion depth of 0.5 cm inside the nasal vestibule; and the shallow angle protocol (or, SA), wherein the spray axis is angled at 45 degrees to the vertical, with a vestibular insertion depth of 1.5 cm. The SA protocol is derived from published findings on alternate spray orientations that have been shown to enhance targeted delivery at posterior infection sites, e.g., the ostiomeatal complex and the nasopharynx. All study participants reported that the SA protocol offered a more gentle and soothing delivery experience, with less impact pressure. Additionally, 60% participants opined that the VP technique caused painful irritation. We also tracked the drug transport processes for the two spray techniques in a computed tomography-based nasal reconstruction; the SA protocol marked a distinct improvement in therapeutic penetration when compared to the VP protocol.

Asymmetric Transverse Acoustic Excitation of a Hollow Cone Spray Sheet With Air Swirl

The objective of this study was to experimentally observe the effects of externally perturbing a hollow cone spray sheet with acoustic excitation. These effects were quantified by measuring changes in the spray breakup length, swirl angle, and oscillatory behaviour of the sheet edge. We used a pressure swirl nozzle embedded into a swirler with 60° vane angles and a geometric swirl no. of SG = 0.981. Water was used to produce a hollow cone spray sheet and air was used as our swirler agent. For asymmetric forcing, only one side of the spray chamber was attached to a transverse duct (aligned perpendicular to the spray axis) along with two speakers. The duct harmonics were found to be 115 Hz, 204 Hz, and 313 Hz. Our experimental modes were also found to be comparable with results obtained numerically using the acoustic solver package from ANSYS. Our results show that for most cases the spray edges, cone angle, and breakup length responds to the acoustic forcing. While the cone angle increased with air swirl, for some cases without acoustic forcing the breakup length increased with air swirl.

Atomization Characteristics of Camelina-Based Alternative Aviation Fuels Discharging From Dual-Orifice Injector

The atomization characteristics of blends of bioderived camelina hydrogenated renewable jet (HRJ) alternative fuel with conventional aviation kerosene (Jet A-1) discharging into ambient atmospheric air from a dual-orifice atomizer used in aircraft engines are described. The spray tests are conducted in a spray test facility at six different test flow conditions to compare the atomization of alternative fuels with that of Jet A-1. The fuel sprays are characterized in terms of fuel discharge, spray cone angle, drop size distribution, and spray patternation. The measurements of spray drop size distribution are obtained using laser diffraction based Spraytec equipment. The characteristics of fuel discharge and cone angle of alternative fuel sprays do not show any changes from that of Jet A-1 sprays. The characteristics of spray drop size, evaluated in terms of the variation of mean drop size along the spray axis, for the alternative fuel sprays remain unaffected by the variation in fuel properties between the alternative fuels and Jet A-1. The measurements on spray patternation, obtained using a mechanical patternator at a distance 5.1 cm from the atomizer exit, show an enhanced fuel concentration in the vicinity of spray axis region for the alternative fuel sprays discharging from the dual-orifice atomizer.

Measurement of High-Speed and High-Number-Density Droplets by Micro-Probe L2F With Mega-Hertz Data Acquisition

A laser 2-focus velocimeter (L2F) has been applied for the measurements of velocity and size of droplets in the core region of diesel spray. The L2F has a micro-scale probe which consists of two foci. The focal diameter is about 2 μm, and the distance between two foci is 20 μm. The feature of this L2F is that the focus is reduced to near the diffraction limit. Investigated was the fuel spray injected intermittently into the atmosphere from an injector nozzle with the orifice diameter of 0.113 mm. The injection pressure was set at 40 MPa by using a common rail system. Measurement positions were located at 10 to 30 mm apart from the orifice exit along the spray axis. Valid data were extracted by a conditional sampling method based on the fact that a droplet passes through both upstream and downstream foci. Measurement result shows that the velocity and size of droplets decrease with the distance along the spray axis. It is clearly shown that the distance between droplets in isotropically dispersed condition decreases with the distance along the spray axis.

Influence of Downstream Distance on the Drop Size Characteristics of an Evaporative Liquid Spray in a Convective Gaseous Medium

Numerical studies have been made to evaluate the interdependence of drop size characteristics and evaporation histories of an atomized liquid spray in a convective medium of uniform free stream at high temperature. With the help of a discrete droplet evaporation model, both the actual drop size distribution and the apparent one, that could have been obtained in practice by light-scattering technique, have been determined numerically at different downstream locations perpendicular to the spray axis. Variations of actual and apparent mass mean diameter and the evaporation rate with the axial distance of the spray have been established. Finally, the influences of pertinent input parameters, namely, the initial Reynolds number of the spray, the ratio of free stream to initial drop temperature and the ratio of free stream to initial drop velocity on the mean diameter and evaporation histories have been recognized.