Inclusion Criteria:

• The subject is healthy. Healthy subjects are defined as individuals who are free from clinically significant illness or disease as determined by their medical history (including family), physical examination, laboratory studies, and other tests.
• They have a history of seasonal allergic rhinitis
• Exhibit a moderate response to 1500 grass pollen grains/m3 after 2 hours in the Vienna Challenge Chamber at screening or within 12 months preceding the screening visit. A moderate response is defined as a total nasal symptom score of at least 6. (Total nasal symptom score is the sum of obstruction, rhinorrhoea, itch and sneeze, each of which has been scored on a scale from 0 to 3).
• They have a positive skin prick test (wheal ? 4mm) for grass pollen at or within the 12 months preceding the screening visit.
• They have a positive RAST (? class 2) for grass pollen at or within the 12 months preceding the screening visit.

• They have demonstrated an ability to use the intranasal spray

  • There are no conditions or factors which would make the subject unlikely to be able to stay in the chamber for 5hours.
• They are capable of giving informed consent which includes compliance with the requirements and restrictions listed in the consent form
• They are available to complete all study measurements

Exclusion Criteria:

• Pregnant or nursing females.
• Female subjects of childbearing potential who are unwilling or unable to use an appropriate method of contraception [i.e. implants of levonorgestrel, injectable progesterone, an acceptable IUD (any IUD with a failure rate of less than 1% per year), oral contraceptives or any other method with a failure rate of <1% per year] for at least two weeks prior to the first dose of study medication and should continue using the same contraceptive measure until the final pregnancy test has been performed (not less than 72 hours after treatment). Alternatively they may be surgically sterilised (refer to section 6.4) or remain abstinent for 2 weeks before exposure to study drug.
• On examination the subject is found to have any structural nasal abnormalities or nasal polyposis, a history of frequent nosebleeds, recent nasal surgery or recent (within 3 weeks) or ongoing upper respiratory tract infection which in the responsible physician's opinion renders the subject unsuitable for participation in the study
• The subject has any respiratory disease other than mild stable asthma that is controlled with occasional use of as-needed short-acting beta-agonists and associated with normal lung function.
• The subject is likely to be unable to abstain from salbutamol use for 8 hours before a challenge
• The subject has a history of drug or other allergy that, in the opinion of the responsible physician, contraindicates their participation.
• The subject has participated in a study with a new molecular entity during the previous 3 months or in any clinical study in the previous 2 months
• The subject is concurrently participating in another clinical study in which the subject is or will be exposed to an investigational or a non-investigational drug or device.
• The subject is currently taking regular (or a course of) medication whether prescribed or not, including steroids, vitamins and herbal remedies (e.g. St. John's Wort). Paracetamol and occasional as needed use of short-acting beta agonists is permitted
• The subject regularly, or on average, drinks more than 3 units of alcohol per day - where 1 unit = ½ pint of beer (284mL), or 1 glass of wine (125mL), or 1 measure of spirit (25mL).
• The subject is at risk of non-compliance with the study procedures/restrictions