Compare the efficacy and safety of an investigational nasal spray compared with placebo nasal spray in the treatment of seasonal allergic rhinitis. Allergic rhinitis is an inflammatory disorder of the upper airway that occurs following allergen exposure. The focus of this study, seasonal allergic rhinitis (SAR), is one type of allergic rhinitis that is triggered by the pollen from trees, grasses, and weeds. Commonly referred to as 'hay fever', it is characterized by sneezing, nasal congestion and pruritus, rhinorrhea, and pruritic, watery, red eyes.