Multifunctional Spray Applicators for Local Administration of Liquid Compounded Drugs

This study evaluated the usefulness of multifunctional spray applicators for topical administration of compounded liquid medications. The research investigated the impact of liquid properties and applicator design on spray characteristics. Six atomizer types (lateral, horizontal long/short tip, and vertical) were tested with five solvents. The study assessed droplet size distribution, dose consistency, priming activations required, actuation force, residual volume, and suitability for suspensions. Results showed that for water, the average droplet size is in the range of approximately 83 to 124 µm. The viscosity has a significant impact on spray performance. In the case of high-viscosity solution of Celugel, some of the liquid does not atomize and is not detected, with only smaller droplets reaching the detector in reduced quantities (from about 33 to 67% compared to the number of water droplets generated). Concurrently, the droplet size ranges, depending on the atomizer type, from approximately 60% to approximately 120% of the water droplet size. Depending on the type of applicator and the fluid being dispensed, the force required to activate the pump mechanism was similar and ranged from 16 to 27 N, enabling comfortable application. Dose consistency was within 25% of manufacturer specifications, though significant differences were noted between vertical nasal applicators. All atomizers required multiple activations, ranging from 4 to 10 presses, depending on the solvent and the type of sprayer. The study emphasizes the importance of selecting the appropriate applicator and considering formulation properties, especially viscosity, for consistent dosing and effective drug delivery in compounded medications.