Aerosol products, development

The aerosol container has enjoyed commercial success ia a wide variety of product categories. Insecticide aerosols were iatroduced ia the late 1940s. Additional commodities, including shave foams, hair sprays, antiperspirants, deodorants, paints, spray starch, colognes, perfumes, whipped cream, and automotive products, followed ia the 1950s. Mediciaal metered-dose aerosol products have also been developed for use ia the treatment of asthma, migraine headaches, and angiaa. 

A number of alternative sizing methods are available, and these are described in Table 8. The American Association of Pharmaceutical Scientists, Inhalation Focus Group conducted a comprehensive review of available methods, which was published in a series of articles identified in the last column of the table. All of the methods described either have been or are currently employed in the development of aerosol products. However, at this time only the inertial samplers, cascade impactors and impingers appear in compendial standards and in regulatory guidelines [44-46], Other methods such as thermal imaging are also under development and may give complementary size information to the current methods. 

Aerosols used for inhalation therapy are generally packaged in containers with metered values. The standard procedure is to discharge the entire contents of the container for assay. For betamethasone dipropionate and betamethasone valerate topical aerosols, the contents are discharged into a volumetric flask and the propellants carefully boiled off. Precautions should be taken, as many of these propellants are flammable. The residue is diluted to volume with isopropanol-acetic acid (1000 1) and filtered [50]. Another approach is to discharge the contents into ethanol or dilute acid. An alternative is to immerse the canister in liquid nitrogen for 20 min, open the canister, evaporate the liquid contents, and dissolve the residue in dichloromethane. A unit spray sampling apparatus for pressurized metered inhalers has been described [51]. The components in an aerosol product that can be the cause of assay variance have been studied [52]. A method to quantify the volatile components of aerosol products has been developed [53]. 

The Committee agreed that the new harmonized flammability test under development by the United Nations Committee of Experts on the Transport of Dangerous Goods should be used when available. The Committee also noted that further collaborative work is required for the determination of droplet size for aerosol products. In addition, the Committee decided that differentiation between residual and space sprays should be maintained. 

A significant effort occurred at the end of the 1990s to develop a new method of inertial sampling that had a greater application in pharmaceutical product development. This resulted in the manufacture of a the Next Generation Cascade Impactor. This device has the advantage of chambers that collect aerosol... 

A steady increase in new aerosol products has occurred in the past 10 years. The majority of these products have come from large pharmaceutical companies with a history of achievement in this field. It can only be hoped that the other products currently in development will soon be commercially available. 

As noted in Chapter 2, fire hazard classification systems are not based on uniform test methodologies for all commodities. In some cases, such as aerosol products, the classification is based on a quantifiable, heat of combustion criteria. However, with most ordinary commodities, the current classification is based on a subjective determination. Additional research to develop objective test methodologies for all commodities, including packaging systems, is needed. 

There is a wide range of personal care and household products packaged in the form of aerosol spray cans. These self-pressurized canisters use a propellant and a valve/atomizer to deliver a liquid aerosol. The original perfume aerosol products (circa 1903) used a CO2 propellant. The first insecticide aerosol product was developed for military use during World War II and used Freon as the propellant. The military version was called the bug bomb, and the first commercial version (1947) was called Jet [40]. Jet appears to also have been the first commercial pressurized aerosol spray product. Within a few years a number of other aerosol spray products appeared in the marketplace, including deodorants, perfumes, suntan enhancers, paints and lacquers [40]. Other modern commercial aerosol... 

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