Mass uniformity of nasal sprays

The uniformity of nasal spray dose delivery was investigated. Four selected nasal sprays commercially available on the European market were checked for their mass uniformity according to the guidelines of the European Pharmacopoeia and recent draft guidelines of the Food and Drug Administration (FDA). Mass uniformity was also determined with simulation of a patient's use daily, and at 3- and 7- day intervals. The influence of the degree of filling and different storage positions on mass uniformity were also investigated. At first usage, all preparations fulfilled the specifications of the Ph.Eur. and the FDA draft guidelines. When patient application was simulated, however, the dose accuracy decreased significantly with some of the preparations with increasing time of non-usage, presumably due to evaporation of liquid in the application system. This is indicated by a loss of weight of the nasal spray flasks observed during simulated weekly usage. Under these conditions (6 days' storage without use, same demands for uniformity of mass of the delivered dose), one of the preparations even failed to meet the Ph.Eur. and FDA limits.