Spray formulations

The selection of vehicle is based on the type of lesion and location of the infection. Solutions are recommended for hairy areas and oozing lesions, while creams are better for moderately scaling and non-oozing lesions. For hyperkeratotic lesions, ointments can be considered. The selected formulation should be applied to the affected area after it is cleaned and dried. The medication should be rubbed into the infected area for improved penetration. Since most patients do not rub in sprays and powders, penetration of the epidermis is minimal, making them less effective than other formulations. Sprays and powders should be considered as adjuvant therapy with a cream or lotion or as prophylactic therapy to prevent recurrence. 

In most of the work, the physicochemical behaviour of the formulations was studied by gas chromatographic estimation at intervals of the residual pheromone remaining in formulations sprayed onto filter papers. The latter were of the silicone-treated "phase-separating" type as these best simulated a leaf surface. When the formulations were exposed in a laboratory wind-tunnel there was little pheromone loss other than by release, at least for the monounsaturated acetates used in most of the preliminary work, and such analyses provided accurate information on release rates under these conditions. However, use of this technique in the field showed that loss of pheromone was very much more rapid than under comparable conditions of temperature and windspeed in the wind-tunnel (2). These results were taken to indicate that there was significant loss of pheromone by degradation under field conditions. 

Diclofenac sodium is an example where cyclodextrin inclusion has a positive effect on the photostability of the gel formulation. Spray dried diclofenac-cyclodextrin complexes in hydroxyethylcellulose gels showed, after three hours of irradiation. 

Number and Location of Observation Wells. The precise amount of pesticide which was applied to the soil surface and is available for leaching is known as the source term. For pesticides which are applied directly to the soil, such as granules or liquid formulations sprayed only onto the soil surface, the source term can be assumed to be equal to the total amount of application. 

The Orahn formulation was administered three times daily before feeding in 40 dogs, and compared to a placebo formulation spray (saline only) over a 24-month period. In order to avoid low blood sugar levels, the dogs were allowed to eat 10 minutes after receiving the Oralin spray or placebo. 

Neutralization of sulfonic acid is similar in the case of either an oleum or a SO3 sulfonation process. The sulfonic acid can be neutralized with aqueous solutions of base that is, KOH, NH4OH, NaOH, or alkanola-mines. The sodium salts are used for formulating spray-dried detergents for household laundry consumption. Ammonium and alkanolamine neutralized salts generally are used in light duty liquid detergents. In general, neutralized salts from oleum sulfonation contain approximately 8 to 10 percent sodium sulfate, where as those from air/SO 3 sulfonation contain only 2 to 3 percent sodium sulfate. 

Prior to application of spray formulations, spray adjuvants are typically added to the insecticide mixture to enhance the efficacy of the active ingredient. Spray adjuvants include surfactants, compounds that impart adhesion and viscoelasticity to spray droplets (e.g., latex), compounds that provide protection from ultraviolet light and reduce volatilization, and activators. The coapplication of these compounds affects organophosphorus insecticide dissipation and transfer to surface runoff Some adjuvants and formulation ingredients are toxicologically significant themselves (e.g., nonylphenol ethoxylates). 

Use Level 0.1-0.3% (on total formulation, spray appllc.) 0.2-0.4% (on total formulation, brush appllc.)... 

Chem. Descrip. Formulated spray adjuvant Ionic Nature Nonionic... 

Uses. Tetrahydrofurfuryl alcohol is of interest in chemical and related industries where low toxicity and minimal environmental impact are important (134). For many years tetrahydrofurfuryl alcohol has been used as a specialty organic solvent. The fastest growing appHcations are in formulations for cleaners (135) and paint strippers (136), often as a replacement for chlorinated solvents (137). Other major appHcations include formulations for crop sprays, water-based paints, and the dyeing and finishing of textiles and leathers. Tetrahydrofurfuryl alcohol also finds appHcation as an intermediate in pharmaceutical appHcations. 

Mixed with additives, urea is used in soHd fertilizers of various formulations, eg, urea—ammonium phosphate (UAP), urea—ammonium sulfate (UAS), and urea—phosphate (urea + phosphoric acid). Concentrated solutions of urea and ammonium nitrate (UAN) solutions (80—85 wt%) have a high nitrogen content but low crystallization point, suitable for easy transportation, pipeline distribution, and direct spray appHcation. 

Solutions. To dehver a spray, the formulated aerosol product should be as homogeneous as possible. That is, the active ingredients, the solvent, and the propellant should form a solution. Because the widely used halocarbon and hydrocarbon propellants do not always have the desired solubiUty characteristics for all the components in the product concentrate, special formulating techniques using solvents such as alcohols (qv), acetone (qv), and glycols (qv), are employed. 

The rate of spray is deterrnined by propellant concentration, the solvent used, and valve and vapor pressure. The pressure must be high enough to dehver the product at the desired rate under the required operating conditions. For example, a windshield ice remover that is likely to be used around 0°C must be formulated to provide an adequate pressure at that temperature. Spray dryness or wetness and droplet size depend upon propellant concentration. 

An emulsion system in which the propellant is in the external or continuous phase is shown in Figure 2b. As the Hquefied propellant vaporizes, it escapes direcdy into the atmosphere, leaving behind droplets of the formulation which are emitted as a wet spray. This system is typical of many water-based aerosols or w/o emulsions. 

Sprays. Aerosol spray emulsions are of the water-in-oil type. The preferred propellant is a hydrocarbon or mixed hydrocarbon—hydrofluorocarbon. About 25 to 30% propellent, miscible with the oil, remains in the external phase of the emulsion. When this system is dispensed, the propellant vaporizes, leaving behind droplets of the w/o emulsion (Fig. 2b). A vapor tap valve, which tends to produce finely dispersed particles, is employed. Because the propellant and the product concentrate tend to separate on standing, products formulated using this system, such as pesticides and room deodorants, must be shaken before use. 

Pharmaceutical powder aerosols have more stringent requirements placed upon the formulation regarding moisture, particle size, and the valve. For metered-dose inhalers, the dispensed product must be deflvered as a spray having a relatively small (3—6 -lm) particle size so that the particles can be deposited at the proper site in the respiratory system. On the other hand, topical powders must be formulated to minimize the number of particles in the 3—6-p.m range because of the adverse effects on the body if these materials are accidently inhaled. 

Hydrocarbons have, for the most part, replaced CFCs as propellants. Most personal products such as hair sprays, deodorants, and antiperspirants, as well as household aerosols, are formulated using hydrocarbons or some form of hydro-carbon—halocarbon blend. Blends provide customized vapor pressures and, if halocarbons are utilized, a decrease in flammabiUty. Some blends form azeotropes which have a constant vapor pressure and do not fractionate as the contents of the container are used. 

Finishing Sprays. Table 3 gives typical aerosol and pump finishing spray formulations. 

Ma.nufa.cture. Finishing sprays are easily prepared as simple solutions of the polymers, neutralizers, plasticizers, fragrance, etc, in ethanol. If water is in the formulation, it must be added last. The aerosol products are filled by the methods described for styling mousses. 

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