Defences respiratory tract

PHMB is very toxic to fish and aquatic life. It is moreover irritating to skin and may cause sensitization by skin contact. It can cause irritation to the eyes, nose and respiratory tract. The PHMB is not compatible with most common swimming pool chemicals. Not compatible with chlorine and chlorinated chemicals and bromine donors. Not compatible with ionic sterilizers, copper based QAC-algicides, anionic detergents, water softening chemicals, persulfate oxidants etc. The defence of the inventors of PHMB is that one should not combine it with other biocides because it should be a bactericide/algicide. But the algicidal properties of PHMB are very weak in brochures and manuals the dose is 200 ppm. 

The respiratory tract is protected by a number of defence mechanisms, including ... 

From a drug delivery perspective, the components of the host defence system comprise barriers that must be overcome to ensure efficient drug deposition as well as retention in and absorption from the respiratory tract. Important non-absorptive clearance mechanisms include mucociliary clearance, alveolar macrophages and metabolism (Figure 6.2). 

The chemical barriers are also important but are sometimes neglected in discussions of defence. To some extent they are specific for each tissue or organ and examples are as follows. Enzymes, such as lysozyme, which digests part of the bacterial coat, are present in many secretions (e.g. tears, milk) acid in the stomach, in the vagina, on the surface of the skin alkali in the small intestine mucus in the intestine, respiratory tract and vagina. 

Aerosols must be respirable, that is, have a mean aerodynamic diameter of less than 5 xm, to ensure that a reasonable proportion will penetrate the respiratory tract defence systems of the nasal passages and the mucociliary clearance mechanisms. 

Clavulanic acid is manufactured by SmithKline Beecham and is sold as oral and parenteral products in combination with amoxycillin under the trade name of Augmentin, and as an injectable product in combination with ticarcillin under the trade name of Timentin. Augmentin is prescribed for infections of the respiratory tract such as bronchitis, and ear, nose and throat infections such as otitis media and sinusitis. It is also indicated for infections of the urinary tract, such as gonorrhoea, and skin and soft tissue infections, which include cellulitis, impetigo and abscesses. Timentin meanwhile is used for the treatment of severe infections in hospitalised patients with impaired or suppressed host defences. 

Modulation of epithelial cell-bacteria interaction through EPs 7630 may protect mucous membranes from microorganisms evading host defence mechanisms. This provides a rationale for the treatment of upper respiratory tract infections with EPs 7630 (727). 

The acute toxicity of L was described in open publications and reviews during the 1940s and some of the defence reports that give more detailed accounts are now in the public records. L has similar effects to SM when applied to the skin or administered by injection. It is acutely lethal at doses of 5-25 mg kg percutaneously, 1-2 mg kg" subcutaneously and 0.5 mg kg" intravenously (Table 2.5) in a range of species. By inhalation, the LCtso is 120-2800 mg min m for a 10 min exposure in a range of species (whole body exposure). Experiments in mice show that L has approximately the same lethality by inhalation alone as by body only exposure. Due to the immediate irritation produced by L the acute toxicity by inhalation should be treated with caution because animals modify their breathing in the presence of irritants. The results of inhalation of L vapour are an immediate irritation followed by acute inflammation of the upper respiratory tract and later pneumonitis and pulmonary oedema within the first 24 hours that is followed by bronchopneumonia. The lesions are very similar to those described for SM inhalation. 

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