Analysis of spray pattern and plume geometry differences between generic and brand-name nasal sprays

Differences in nasal spray deposition sites within the nasal cavity are considered factors that affect the bioequivalence of nasal sprays for local action. This study employed a semi-automated quantitative analysis approach using Fiji (ImageJ) and R software to evaluate the equivalence of spray pattern (SP) and plume geometry (PG) between brand-name and generic nasal spray formulations containing fluticasone propionate (FP) or fluticasone furoate (FF) marketed in Japan. Deposition patterns in the nasal cavity model were also evaluated. In addition, we investigated formulation factors, such as device structure and formulation rheology, that influence differences in spray characteristics by evaluating the SP after replacing the contents in the formulation. SP exhibited distinct shapes, with statistically significant differences in area, ellipse fit parameters, and major (D max ) and minor (D min ) axes. The PG parameters, including angle and width, were over 1.1 times larger in generic products than in each brand-name product. These results indicate that generic products are not equivalent to brand-name products in the SP and PG. Deposition patterns in the nasal cavity model also varied, with deposition regions correlating with SP and PG parameters. The observed differences were associated with both device and formulation factors, including nozzle structures beyond the orifice diameter, and solution properties, such as apparent viscosity. These results highlight the importance of controlling the equivalence of SP and PG in nasal sprays marketed in Japan as a step towards ensuring equivalent nasal deposition. Developing equivalent formulations requires precise control of both the device and formulation solution properties. • Evaluating SP and PG using Fiji (ImageJ) and R software for nasal sprays. • SP and PG showed non-equivalence between brand and generic nasal sprays in Japan. • SP and PG parameters correlated with drug deposition in the nasal cavity model. • Both device and formulation solution factors influenced SP and PG. • SP and PG are crucial for pharmaceutical equivalence in nasal spray products.