The present invention relates to the field of compounds, compositions and uses therefore, in oral and/or nasal administration prophylaxis and/or treatment of respiratory disorders. More particularly the invention relates to nitrosated and nitrosylated compounds, compositions comprising such compounds, which can optionally be unsubstituted or substituted with at least one NO or NO2 moiety, and a compound that donates, transfers or releases nitric oxide as a charged species, i.e., nitrosonium (NO+) or nitroxyl (NO), or as the neutral species, nitric oxide (NO.); and uses for each of them.
A broad spectrum of respiratory diseases and disorders have been recognized, many of which have overlapping and interacting etiologies. One of the most widespread and prevalent of these diseases in western populations is the chronic disease referred to as “asthma”. Other such disorders are also characterized by acute pulmonary vasoconstriction such as may result from pneumonia, traumatic injury, aspiration or inhalation injury, fat embolism in the lung, acidosis inflammation of the lung, adult respiratory distress syndrome, acute pulmonary edema, acute mountain sickness, post-cardiac surgery, acute pulmonary hypertension, persistent pulmonary hypertension of the newborn, prenatal aspiration syndrome, hyaline membrane disease, acute pulmonary thromboembolism, heparin-protamine reactions, sepsis, status asthmaticus or hypoxia (including iatrogenic hypoxia) and other forms of reversible pulmonary vasoconstriction. Such pulmonary disorders also are also characterized by inflammation of the lung including those associated with the migration into the lung of nonresident cell types including the various leucocyte subclasses. Also included in the respiratory disorders contemplated are cystic fibrosis and other diseases which are characterized by excess mucosal secretion. Other physiological events which are contemplated to be controlled include platelet activation in the lung.
Asthma is a major and disabling obstructive respiratory disease associated with significant morbidity and mortality. The term “asthma” has been used to describe a condition which is characterized by widespread fluctuations in the diameter or caliber of bronchial airways over short periods of time resulting in changes in lung function. The resulting increased resistance to air flow produces symptoms including breathlessness (dyspnea), chest constriction or “tightness” and wheeze. The term as used is not currently limited to a disorder or disease resulting from any specific cause or causes, rather it is characterized by its clinical manifestation. A true immunological mechanism may or may not be a factor in the etiology of an individual asthmatic condition. Further, characteristic wheezing may not be present in particularly severe attacks where transport of air is completely obstructed. Regardless of the cause, asthma in all sufferers is characterized by reversible hyperresponsiveness of tracheal bronchial smooth muscle resulting in its contraction and interference with normal respiration. The lungs of patients who die of asthma are usually pale pink, hyperinflated, and fail to collapse after their removal from the chest. Many of the airways throughout the bronchial tree are occluded by thick mucus plugs which are infiltrated with various types of leukocytes, including mast cells. The smooth muscle of the airways is hypertrophied. The bronchoconstriction or bronchospasm characterized by asthmatic attacks causes obstruction to air flow which necessitates a forced exhalation and maintenance of artificially elevated functional air reserve capacity to keep the airways open. The resultant lung hyperinflation places a significant stress on the cardiovascular system (particularly the right ventricle) which can lead to a consequent cardiovascular event. One possible result is a progressive decrease in cardiac output referred to as “cardiopulmonary tamponade”. Most deaths resulting from asthma are caused by a condition referred to as “status asthmaticus,” which is essentially an intensely severe and bronchospasm that is unresponsive to treatment.
Various categories of drugs are known to be useful in the inhalation of treatment of asthma. These include β2 agonists (such as salmeterol, albuterol, metaproternol, terbutaline, pirbuterol, rimiterol, clenbuterol, bitolterol and repreterol, adrenalin, isoproterenol, ephedrine, orciprenlaine, fenoterol and isoetharine); anticholinergic agents (such as atropine, ipratropium, flutropium, tiotropium and rispenzepine) and mast cell stabilizers (chromolyn and nedocromil). Selective β agonists have recently been developed with fewer cardiotonic side effects than those previously employed and are now considered suitable therapeutics for management of bronchitis and, particularly, emphysema, for which there previously had not been a suitable effective form of therapy.
Although corticosteroids are not generally indicated for routine use in the treatment of asthma, whether acute or chronic, they are used in large doses in the treatment of status asthmaticus. Nonetheless, the use of inhaled corticosteroids for the treatment of bronchial asthma has increased in recent years. Most frequently beclomethasone dipropionate, triamcinolone acetonide or flunisolide can be used to reduce or replace oral corticosteroid therapy, particularly in the treatment of children. This avoids or reduces bronchial reactivity and behavioral toxicity. See Cott and Cherniack, Steroids and “Steroid-sparing Agents in Asthma”, New Engl. J. Med., 318:634-636, 1988.
Cystic fibrosis is a multi-organ disorder of the exocrine glands which is congenital, lethal and affects all populations, particularly European and North American populations. Primary effects of cystic fibrosis are in the secretory glands, particularly mucous secretion. One of the organ systems most effected by cystic fibrosis is the lungs and respiratory tract. Therapy is as yet only symptomatic as the underlying genetic defect has yet to be characterized.