An Ongoing Improvement Process
As with other evolving classes of medicines, there have been modifications of INS over time. Goals for improvement have included decreased systemic bioavailability^1,2 and increased glucocorticoid receptor binding affinity and selectivity^3,4 in the newer products (e.g. fluticasone propionate, mometasone furoate, fluticasone furoate) compared with older products (beclomethasone dipropionate).

Decreased bioavailability is important, not only for minimizing the risk of corticosteroid adverse effects for allergic rhinitis patients, but also for reducing the corticosteroid load in patients with asthma who require intranasal corticosteroids for their allergic rhinitis and inhaled steroids for their lower airway disease. There is a wealth of published scientific research that has clearly demonstrated how, in patients with asthma and concomitant allergic rhinitis, there is immunological and physiological cross-talk because of the upper and lower airway inflammation.⁵ Therefore, it is critical to treat both conditions in these patients to gain optimal disease control.⁶

Taking Into Account the Concerns of Patients when Designing Intranasal Corticosteroids Devices
While efficacy and safety are of paramount importance in the development of new products and formulations, in recent years a number of studies have been published that evaluate the sensory attributes of INS products (e.g. taste, smell, and delivery volume) from a patient’s perspective. For example, in a double-blind cross-over study, 100 allergic rhinitis patients were randomized to mometasone furoate nasal spray (MFNS) or fluticasone propionate nasal spray (FPNS).⁷ At the end of each treatment period, patients rated the study drugs by completing a product sensory attributes questionnaire. Significantly fewer patients perceived scent/odor (p<0.001), taste (p=0.002), and aftertaste (p=0.007) immediately and/or two minutes after administration with MFNS compared with FPNS. Similarly, twice the number of patients preferred MFNS over FPNS for each of these individual assessments (p=0.0005 for scent/odor, p=0.005 for taste and aftertaste). The consensus of this and other studies^7,8 is that sensory attributes may influence a patient’s preference among INS with otherwise similar safety and efficacy profiles, and that compliance may be compromised with INS products that have unpleasant attributes, such as a noticeable aftertaste, prominent odor, or a spray delivery volume that causes excess medication to run down the back of the throat. As the evidence continues to mount, product sensory attributes will likely play an important role in physician prescribing behavior.

Room for Improvement?
In the words of poet Ralph Waldo Emerson: “Build a better mousetrap and the world will beat a path to your door.” This highlights another important facet of the ‘experience’ of patients that has received little research attention: the design of INS delivery devices. The design of asthma inhalation delivery devices has undergone significant evolution, from earlier ‘Rube Goldberg’ designs to an array of sophisticated devices that are compact, portable, reliable, and easy to use. Some of the newer devices come equipped with integrated dose counters.⁹ In contrast to asthma delivery devices, evolution in the design of INS delivery devices has not run in parallel with improvements in the INS medications they contain. At a minimum, they are reliable and deliver accurate doses of medication when used properly. However, in light of the emerging importance of product sensory attributes, nasal spray device design may also influence both the preference of patients and the choice of physicians when considering available prescription INS medications with similar safety and efficacy profiles.