Category: Formulation and Quality
Purpose: Nasal spray devices are designed to deliver a plume of droplets containing pharmacologically active materials to the nasal cavity. By altering the viscosity of the formulation, the residence time of the drug can be increased in the nasal cavity, thereby increasing drug absorption. Previous work has shown that the spray droplet size increases with viscosity for aqueous formulations1-5, and has been attributed to problems atomizing higher viscosity formulations. Furthermore, although non-aqueous formulations do not produce an elegant spray, increasing the actuation force helps with atomization. The purpose of this study was to determine whether the spray characteristics/trends are comparable for aqueous and non-aqueous formulations.
Methods: A series of proprietary aqueous and non-aqueous pharmaceutical formulations were sprayed using 100µL multi-dose nasal pumps (Aptar Pharma, Eigeltingen, Germany). A Vereo® NSx automated actuator (Proveris Scientific Corp., Marlborough, MA) was used to actuate the devices. The plume was characterized using a SprayVIEW® measurement system (Proveris Scientific) and a Spraytec® system (Malvern Instruments, Malvern, UK) for spray pattern and droplet size distribution respectively. Formulation viscosity was measured at 25oC using a RVDV3T cone and plate rheometer with a CPA40Z cone (AMETEK Brookfield, Middleboro, MA), and density was measured at 22-23oC using a DMA 35 density meter (Anton Paar USA Inc., Ashland, VA).
All characterization data was recorded at 3cm from the tip of the device. In order to adequately atomize the non-aqueous formulations, an actuation velocity of 72mm/s and an acceleration of 3000mm/s2 were used.
Results: The following figures show the viscosity, density and spray plume characteristics of the aqueous and non-aqueous formulations. The graphs show the mean and range of results.