Inhalant properties types

The two main determinants for medicine deposition in the respiratory tract are the aerodynamic size distribution of the aerosol and the manoeuvre with which the aerosol is inhaled. They govern the mechanisms that are respraisible for particle deposition in the lungs. By varying the inhalation manoeuvre, not only the distribution in the airways for the same aerosol is changed in many cases also the amount and properties of the delivered fine particle dose are affected. The complex interplay between inhalation manoeuvre, aerosol properties and site of deposition has led to many misconceptions regarding the best inhaler choice for individual patients and the way these inhalers need to be operated to achieve optimal therapy for the patient. In this chapter the medicine deposition mechanisms for inhaled aerosols are explained as functions of the variables involved. In addition, the working principles of different inhaler types are described and it is discussed how their performance depends on many inhalation variables. Finally, some persistent misconceptions in the literature about the most preferable dry powder inhaler properties and performance are umaveUed. 

Radon constitutes a serious problem because, being a heavy gas, it collects in such places as basements and mine shafts. When inhaled, radon decays in areas where little penetration is require to cause tissue damage. Radiation from a and (3 decay is not of a highly penetrating type, but inside the lungs it does not have to be in order to still cause damage. Table 15.10 shows several properties of the noble gases. 

Even when the appropriate inhaler is chosen, the influence of the disease state cannot be ignored. Disease states can influence the dimension and properties of the airways and hence the disposition of any inhaled drug. Thus, great care must be taken when extrapolating the findings based on intratracheal administration to different animal species in order to predict deposition profiles after inhalation of aerosol formulations by patients suffering from airway disease. DPIs are not appropriate in many diseases when the ability to have sufficient airflow is hindered. Since many diseases that we would like to treat via pulmonary administration of biomolecules cause a decrease in airflow, we must be careful in the decision of which type of inhalation mechanism to choose. 

Refinements of the RfC have utilized mechanistic data to modify the interspecies uncertainty factor of 10 (Jarabek, 1995). The reader should appreciate that with the inhalation route of exposure, dosimetric adjustments are necessary and can affect the extrapolations of toxicity data of inhaled agents for human health risk assessment. The EPA has included dosimetry modeling in RfC calculations, and the resulting dosimetric adjustment factor (DAF) used in determining the RfC is dependent on physiochemical properties of the inhaled toxicant as well as type of dosimetry model ranging from rudimentary to optimal model structures. In essence, the use of the DAF can reduce the default uncertainty factor for interspecies extrapolation from 10 to 3.16. 

Funatsu, G., Funatsu, M. (1970). Isolation and chemical properties of various types of ricin. Jpn. J. Med. Sci. Biol. 23 342-4 Gareth, D., Griffiths, G.D., Rice, P., Allenby, A.C., Bailey, S.C., Upshall, D.G. (1995). Inhalation toxicology and histopa-thology of ricin and abrin toxins. Inhal. Toxicol. 7 269-88 Gill, D.M. (1982). Bacterial toxins a table of lethal amounts. Microbiol. Rev. 46 86-94. 

Some of the major types of abused chemicals in inhalants are discussed below. Unlike the properties of other drugs of abuse, the word inhalants encompasses many dififerent types of chemical molecules that are grouped together because of their shared method of administration. Due to this broad classification, chemicals abused as inhalants are a large group of molecules. 

Lactose is widely used as a filler or diluent in tablets and capsules, and to a more limited extent in lyophilized products and infant formulas.Lactose is also used as a diluent in dry-powder inhalation. Various lactose grades are commercially available that have different physical properties such as particle size distribution and flow characteristics. This permits the selection of the most suitable material for a particular application for example, the particle size range selected for capsules is often dependent on the type of... 

Sulfobutylether P-cyclodextrin can form noncovalent complexes with many types of compounds including small organic molecules, peptides, and proteins. It can also enhance their solubility and stability in water. The first application of sulfobutylether P-cyclodextrin was in injectable preparations it can also be used in oral solid and liquid dosage forms, and ophthalmic, inhalation, and intranasal formulations. Sulfobutylether P-cyclodextrin can function as an osmotic agent and/or a solubilizer for controlled-release delivery, and has antimicrobial preservative properties when present at sufficient concentrations. 

Precautions DE is considered nontoxic to mammals, but the same properties that make it lethal to pests also cause it to irritate mucous membranes. Wear a dust mask when applying DE to avoid inhaling the particles. Don t apply the dust where children are likely to encounter it. Don t confuse pool-grade DE with the garden variety the type used in pools is chemically treated and poses a severe respiratory hazard. DE is nonselective and will kill beneficial insects. Rain will dilute or wash away DE and mix it into the soil, but the DE will retain its insecticidal properties. 

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