Inhalation therapy respiratory

Aerosolised medicines have been used for centuries to treat respiratory diseases, with inhalation therapy for the airways focused primarily on the treatment of asthma and chronic obstructive pulmonary disease (COPD). The development of new products for delivery to the lungs for these respiratory diseases includes new steroids and beta agonists plus combination products featuring both agents. New classes of anti-asthma medication are also being developed for inhalation with the aim of delivering them directly to the inflamed airways. 

Pulmonary deposition of an aerosol preparation is determined primarily by its size. Aerosols with a mass median aerodynamic diameter of 1-5 xm produce the best therapeutic results and are the target particle size for inhalation therapy. These small particles penetrate deep within the respiratory tract to ensure drug deposition in peripheral airways. The cross-sectional area (cm ) of the lung increases dramatically at the level of the respiratory zone therefore, the velocity of gas flow during inspiration rapidly decreases at this level. Moderate-sized particles (5-10 (xm) frequently settle out by sedimentation in larger more central airways because the velocity of gas falls rapidly in the region of the terminal bronchioles. 

Advances in the equipment for the administration of aerosol medication to horses have facilitated the widespread use of inhalation therapy in equine medicine. Newer aerosolization devices ease administration and make pulmonary drug delivery efficient. Aerosol therapy is likely to become the mainstay of treatment for horses with heaves and may prove beneficial in the treatment of infectious respiratory disease in horses. 

Duvivier D. Votion D, Roberts C et al 1999b Inhalation therapy of equine respiratory disorders. Equine Veterinary Education 11 124-130 Emerman C, Cydulka R, Skobeloff E 1996 Survey of asthma practice among emergency physicians. Chest 109 708-712... 

The use of inhalation therapy has been applied mainly to the treatment of asthma and bronchitis. There is an increasing awareness that current treatment is inadequate and that the incidence of asthma is on the rise [31]. Indeed, it has been shown that an apparent increase in the prevalence of asthma at childhood has occurred in recent years [32]. Of particular recent interest is the structure-activity relationships associated with drug residence times in the respiratory tract. 

Clinical complications related to the use of nebulizers have been observed. Facial dermatitis with superimposed bacterial infections have been described and are caused by the prolonged use of a face mask [145]. Contamination of the small-volume nebulizers has been linked with oropharyngeal colonization [146,147]. In one report, infections were seen four times more frequently in patients receiving inhalation therapy for respiratory diseases than in those who are not. At least one example of death resulting from contamination has been reported. 

Zierenberg B. Boehringer Ingelhiem nebulizer (BINeb)—a new approach to inhalation therapy. In Respiratory Dmg Delivery V Dalby RN, Byron PR, Farr SJ, eds. Interpharm Press Phoenix AZ, 1996 187-194. 

For inhalation treatment of respiratory diseases, a pharmaceutical DNase I aerosol is on the market. Pulmozyme is a sterile solution for respiratory use at a concentration of 1000 Genentech Units/mL [22]. It contains 1 mg/mL rhDNase, sodium chloride as a tonicity modifier, calcium chloride as a stabilizer, and water for injection. Since deamidation is rapid at high pH and aggregation occurs at low pH, a nearly neutral solution (pH 6.3) is required. It is administered by means of a compressed air-driven nebulizer. Each 2.5-mL single-unit ampule will deliver 2.5 mg of rhDNase to the nebulizer chamber. The efficacy of DNase inhalation therapy largely depends on the aerosol quality and characteristics, which determine the respirable fraction. Significant differences were found between the different aerosol drug-delivery systems [68,81]. 

Zierenberg B, Eicher J, Dunne S, Ereund B. Boehringer Ingelheim Nebulizer BINEB, a new approach to inhalation therapy. In Respiratory Drug Delivery V. Buffalo Grove, IL Interpharm Press, 1996 187-193. 

Recognizing the fact that pMDIs were the most widely used form of inhaled therapy and available in all markets for all types of inhaled respiratory medicine, it was felt that their use did justify an essential use exemption from the Montreal Protocol. Dry-powder devices were recognized as an alternative for many, but they were not available in all countries for all medicines and were not always suitable for the young and those with low inspiratory flow rates also, they may not be suitable in certain humid climates. In some markets their extra cost would also deprive many of necessary treatment. 

Zierenbeig, B., Eieher, J., Dunne, S., and Freund, B. 1996. Boehringer Ingelheim nebulizer BINEB anew approach to inhalation therapy. In R. N. Dalby, P. R. Byron, and S. J. Farr, eds., Proceedings of Respiratory Drug Delivery V. Interpharm Press, Buffalo Grove, pp. 187-193. 

Pulmonary administration of medicines currently has the primary objective to achieve local effects in the respiratory tract of patients with chronic diseases like asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF). For half a century, inhalation therapy has been the cornerstone in the management of these diseases and the often life-time therapies aim to suppress inflammatory processes and bacterial infection in order to reduce hospitalisations and to improve the patient s quality of life. They also give relief to the patient in moments of bronchoconstriction. The advantages of pulmonary administration of medicines for local treatment are well known. The active substances are delivered directly to the site of action which leads to a faster response than via the systemic route. It may also result in higher local active substance concentrations and this could reduce the total dose by as much as a factor 10 compared to oral or intravenous administration. This has the advantage that systemic side effects are reduced and in combination with being a non-invasive method of administration, inhalation therapy may lead to better patient compliance. 

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