ABSTRACT
Inhalation is a convenient way to deliver drugs to the respiratory tract in the treatment of respiratory diseases. For dry powder inhalers (DPI's), the principle of operation is to use the patient-generated inspiratory flow as energy source for emptying of the dose system and the delivery of fine drug particles into the respiratory tract. Resistance to airflow of the inhaler device is a major determinant for the inspiratory flow profile through the dry powder inhaler that can be generated by the patient. Therefore, resistance to airflow is one of the design parameters for DPI's, that could be used to control the inspiratory flow profile, and is one of the parameters to optimise particle deposition in the airways. In this study the effect of resistance to airflow on different parameters of the inspiratory flow curves as generated by healthy subjects, asthmatics and COPD patients was determined. As a result of increased resistance to airflow, the peak inspiratory flow (PIF), the flow increase rate (FIR) and the inhaled volume to reach PIF is decreased. On the other hand, the total inhalation time as well as the 80% dwell time is increased. In general, tuning of the resistance to airflow in the design of a dry powder inhaler may improve the drug deposition in the respiratory tract.
Subject(s)
Administration, Inhalation , Airway Resistance , Nebulizers and Vaporizers , Adult , Asthma/physiopathology , Female , Humans , Male , Pulmonary Disease, Chronic Obstructive/physiopathology , Respiratory Mechanics/physiologyABSTRACT
Data from two questionnaires held in 1985 and 1987 among 68 and 49 PTB patients respectively; revealed that many patients visited healing churches but few admitted having consulted traditional healers; that financial expenses for transport outweighed hospital charges; that lower educational levels were not associated with poorer compliance to therapy; that health education had improved significantly in two years time. It is concluded that intervention with liaison health workers and simple health education results in improved outcome in rural service tuberculosis programme
