disperse system123

7/29/2019 Disperse System123

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By: Chesmar Macapala


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CLASSIFICATION and TYPES OF GELS TWO GENERAL CLASSIFICATION:

1.) Inorganic Hydrogels- are usually two-phase systems

Example: Aluminum Hydroxide Gel and BentoniteMagma


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2.) Organic Gels- are usually single phase systems andmay include gelling agents (Carbomer) and those that

contain an organic liquid (Platibase)


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Second Classification of Scheme: 1.) Hydrogels- include ingredients that are dispersible

as colloidals or soluble in water and it also includesorganic and inorganic hydrogels, natural and syntheticgums.

Examples: Silica, Bentonite, Tragacanth, Pectin,

Sodium Alginate, Methylcellulose, Alumina, andCarboxymethylcellulose


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Hydrogel- Silica Alumina Gel


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Organogels- include the hydrocarbons, animal, andvegetable fats, soap base greases and the hydrophilic

organogels Examples- Hydrocarbon- Jelene or Plastibase


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Preparation of Magmas and Gels 1.) By freshly precipitating the disperse phase

2.) By direct hydration in water


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MAGMAS and MILKAre aqueos suspensions of insoluble, inorganic drugs

and differ from gels mainly because the suspendedparticles are larger.


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AEROSOLSAre pressured dosage forms containing one or more

active ingredients which upon actuation emit a finedispersion of liquid and/or solid materials in gaseousmedium


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Advantages of the Aerosol Dosage

forms -It may be easily withdrawn from the package without

contamination

-Hermetic character -Doesnt need to touch the affected area thus reducing

irritation

-Physical form and particle size of the product may be

controlled which may contribute to the efficacy of adrug

-Aerosol application is clean process requiring little orno wash up by the user.


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Aerosol PrincipleAerosol formulation consists of 2 components:

1.) Product Concentrate

2.)Propellant


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Examples of Propellants Carbon dioxide

Nitrogen

Nitrous Oxide Fluorinated Hydrocarbons


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The effectiveness of the aerosol

depends on: 1.) proper combination of formulation

2.) container

3.) valve assembly


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AEROSOL SYSTEMS SPACE AEROSOLS- usually operate at pressures

between 30-40 psig at 70F and may contain as much as85% propellant

SURFACE AEROSOLS- commonly contain 30-70%propellant with pressures between 25-55psig at 70F

FOAM AEROSOLS- usually operate between 35-55psig at 70F and may contain only 6-10% propellant.


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TWO-PHASE SYSTEM-

1.) liquid phase propellant and product concentrate

2.)the vapor phase

THREE-PHASE SYSTEM-

1.)layer of water immiscible liquid propellant

2.)layer of highly aqueous product concentrate 3.)vapor pressure

COMPRESSED GAS SYSTEM -compressed rather liquefied, gases may be used to

pressure aerosols.


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CONTAINERS 1.) Glass, uncoated or plastic coated

2.) Metal, including tinplated steel, aluminum, and

stainless steel 3.) Plastics


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Selection of containers for an

aerosol product is based on: -Its adaptability to production method

-Compatibility, with formulation components

-Ability to sustain the pressure intended for theproduct

Interest in design and aesthetic appeal of the container

Cost


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VALVE ASSEMBLY It functions to permit the expulsion of the contents of

the can in the desired form , at desired rate, and in theproper amount of dose.


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MDIs Each metered dose is delivered thru the mouthpiece

upon actuation of the aerosol units valve


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PARTS OF AEROSOL VALVEActuator

Stem

Gasket Spring

Mounting Cup

Housing

Dip tube


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AEROSOL VALVE


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Testing the Filled Containers Leaks

Weakness in the valve assembly or container

Proper functions of the valveValve discharge rate

Particle size distribution of the spray

For accuracy and reproducibility of dosage when using

metere valves

disperse system123

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