Mucociliary clearance reduction

Such changes (decrease of ciliated cells with simultaneous increase of the secretion) are noted for smokers (Gouveia et al., 1982 Mathe et al., 1983) and cause a reduction of the mucociliary clearance. This reduction of the mucociliary clearance, associated with an increased adsorption of the respiratory syncytial virus (RSV) (Donelly, 1996), could also explain the extraordinarily high morbidity and mortality for respiratory infections of children with vitamin A deficiency in developing coimtries (Sommer, 1993). 

Several age-related changes contribute to the high incidence of infections in geriatric patients. There appears to be a reduction in host defenses in the elderly, manifested in the increase in both serious infections and cancer. This may reflect an alteration in T-lymphocyte function. In the lungs, a major age and tobacco-dependent decrease in mucociliary clearance significantly increases susceptibility to infection. In the urinary tract, the incidence of serious infection is greatly increased by urinary retention and catheterization in men. 

Direct toxic effects such as irritation, inflammation, or increased permeability will bring about symptoms such as the sneeze reflex, nasal discomfort, and hypersecretion with the possibility of underlying pathological changes such as squamous metaplasia, cilia erosion, plasma exudation, epithelial necrosis, inflammatory remodeling, or neutrophil accumulation. Indirect adverse effects can also occur and any alteration to normal nasal homeostasis should be avoided. For example, a reduction in mucociliary clearance can cause rhinitis, sinusitis, and an increased susceptibility to airway infections, and consequently ciliary movement should not be altered by any nasal medication. In the context of absorption enhancers, the rate and extent of recovery of normal nasal epithelial function after nasal administration is a prime consideration. 

Microspheres prepared with bioadhesive polymers have some additional advantages they assure much more intimate and prolonged contact with the mucous layer and improved drug absorption due to additional delay in mucociliary clearance. Bioadhesive microspheres can significantly improve patient compliance as all the advantages described lead to reduction in the frequency of drug administration [3,74]. 

Colthorpe et al. showed that the mucociliary clearance is the elimination pathway that contributes most to the reduction of bioavailability of insulin, at least in the rabbit model they studied. Thus, the less insulin is deposited on the conducting airways and the more that gets into the non-ciliated gas exchange spaces, the higher is the bioavailability. Similar conclusions were reached studying the pulmonary absorption of growth hormone in the same model. The... 

Twelve patients with chronic obstructive bronchitis were given a 4-day treatment with 1,8-cineole (4 X 200 mg/day). By measuring the reduction in percentage radioactivity of an applied radioaerosol, signi cant improvements in mucociliary clearance were demonstrated at the 60 and 120 min after each administration, (Dorow, 1989). 

In a randomized, double-blind, placebo-controlled study of 51 patients with COPD, 1,8 cineole (3 X 200 mg/day) was given for 8 weeks. For the objective lung functions of airway resistance and speci c airway resistance, there was a clinically signi cant reduction of 21% and 26%, respec tively. The improvement was attributed to a positive in uence on disturbed breathing patterns, mucociliary clearance, and anti-in ammatory effects (Habich and Repges, 1994). 

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