First quarter aerosol
Aerosol (aerosol) refers to the effective components and the appropriate ejection agent is loaded with a special valve system pressure sealed in containers made of transparent liquid, mixed suspension or emulsion, used by propellant pressure contents was fog particle (or foam) spray formulations.
When in use, the pressure of the propellant by the contents of quantitative or non quantitative ejection.
In medicine ejection fine mist, the particle diameter less than 50um; also can make the medicine ejection is smoky, foamy or trickle.
Smoke like products such as: aerosol spray, aerosol spray, spray, oil, etc.
Is foam products such as: automotive foam cleaning agent, hair mousse etc.
A trickle of products such as: wasp spray agent; fire extinguisher spray far products
Two, aerosol composition
The aerosol is composed of propellant, active ingredients and additives, pressure vessel and valve system.
The propellant (propellents) is the power of effective components ejected, sometimes with the effective components of solvent effect.
1, a propellant requirements: the vapor pressure at room temperature should be greater than atmospheric pressure; should be non-toxic, no sensitization and stimulation; inert, and drug reaction; colorless, odorless, tasteless, cheap and easily obtained.
The propellant can be divided into hydrocarbons, freon-12 hydrocarbons and compressed gas three.
The main varieties are butane and isobutane, propane and butane mixed gas (LPG), dimethyl ether (DME) is the most commonly used propellant.
(2) freon-12 hydrocarbons
(Freon), also known as Freon propellant is more expensive, the domestic is not commonly used
The characteristics of low boiling point, at room temperature the vapour pressure slightly higher than the atmospheric pressure, easy to control; stability properties, is not easy to burn; liquefied density, tasteless, no odor, low toxicity; insoluble in water, as a fat soluble drugs solvent
(3) compressed gas
The main varieties of carbon dioxide, nitrogen and nitric oxide, etc., in the aerosol, the basic need, commonly used in spray.
The amount of 3, and the vapor pressure of propellant
In general, the amount of large, high vapor pressure, high injection ability, and vice versa.
The general hybrid propellant, by adjusting the dosage and vapor pressure to adjust the injection ability of the.
(two) effective ingredients and additives
According to the nature of the product and the requirements of the decision to prepare suitable type of aerosol, so as to determine the use of some of the potential solvents or additives.
(three) pressure vessel
Aerosol containers must not with active ingredients, additives and propellant, work pressure, light, cheap etc..
(four) valve system
Valve system requires strong, durable, structural stability; valve material to the content of inert, its processing should be precise.
Five, aerosol preparation
(a) of the type and the example of aerosol
1, solution type aerosol