Inclusion criteria:

• History of asthma with exclusion of other significant pulmonary disease.
• Body Mass Index between 19-31 kg.m-2.
• Subjects will be assigned to group 1(mild to moderate) or Group 2 (severe asthmatics) depending on their Lung Function test results.

Exclusion criteria:

• As a result of medical interview, physical examination or screening investigation the physician responsible considers the subject unfit for the study.
• History of drug or other allergy, which, in the opinion of the responsible physician, contra-indicates their participation.
• Subject is female who is pregnant or lactating.
• Currently or planning to take during the study regular medication (including over-the-counter) except for medication allowed in inclusion criteria.
• Having participated within 30 days or 5 half-lives, whichever is longer of the first dose in a study using new molecular entity, or the first dose in any other study investigating drugs or having participated within one month of the first dose in a study with invasive procedures.
• History or current evidence of an upper or lower respiratory infection or symptoms (including common cold) within 2 weeks of baseline assessments.
• History of abnormal bruising or bleeding.
• History of alcohol or drug abuse.
• Doing night-shift work within at least 5 days prior to dosing until completion of the study.
• Anticoagulants except low dose of Aspirin (80 mg per day) (for bronchoscopy).
• Beta blockers except for low dose Atenolol (25 mg/day) or Metoprolol (50 mg/day) (for bronchoscopy).
• Use of Cytochrome P450 inhibitors.
• History of hypersensitivity to any of the following medications: Lidocaine, Fentanyl, Versed, Demerol, Midazolam, Epinephrine, Flumazenil and Naloxone.
• History of hypersensitivity to bronchodilator (such as Albuterol).

In addition, the following additional exclusion criteria must apply to mild to moderate persistent asthmatics on regular inhaled steroids:

• Changed asthma medication within the 4 weeks prior to screening.
• Has had an asthma exacerbation in the previous month.
• Known sensitivity or allergy to prednisolone.
• Current use or use within the previous 3 months of oral corticosteroids.
• Current use of Methotrexate, cyclosporine and PDE inhibitors
• History of tuberculosis, diabetes mellitus, osteoporosis, severe hypertension, glaucoma , severe affective disorder and peptic ulceration.

In addition, the following additional exclusion criteria must apply to severe persistent asthmatics with clinical controlled asthma symptoms:

• Changed asthma medication within the 4 weeks prior to screening.
• Has had an asthma exacerbation in the previous month.
• sensitivity or allergy to prednisolone.
• History of tuberculosis, diabetes mellitus, osteoporosis, hypertension, glaucoma, severe affective disorder and peptic ulceration.
• Current use or use within the previous 4 weeks of oral prednisolone or equivalent of greater than 20mg daily.
• Current use of Methotrexate, cyclosporin.