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level: level 7 - GELS AND GELLING AGENTS

Questions and Answers List

level questions: level 7 - GELS AND GELLING AGENTS

Question	Answer
semisolid systems consists of dispersions made up of either small inorganic particles or large organic molecules enclosing and interpenetrated by a liquid. clear as water or turbid	Gels
Gels in which macromolecules are distributed so that no apparent boundaries exist between them and the liquids are called __	Single- Phase Gels
When the Gel mass consists of floccules of small, distinct particles, the gel is classified as __ Frequently called Magma or a Milk	Two-Phase System
are usually two phase systems such as Aluminum Hydroxide Gel and Bentonite Magma, Milk	Inorganic hydrogels
are usually single phase systems and may include such as gelling agents as Carbomer and Tragacanth and those that contain an organic liquid, such Plastibase	Organic Gels
GELLING AGENTS:	1 Carbomer 2 Tragacanth 3Plastibase (contain an organic liquid)
- include ingredients that are dispersible as colloidals or soluble in water and include organic hydrogels, natural and sythetic gums and inorganic hydrogels ex. silica, bentonite, tragacanth, pectin, sodium alginate, methylcellulose, sodium carboxymethylcellulose and alumina	Hydrogels
- include the hydrocarbons, animal and vegetable fats, soap base greases and ex. Hydrocarbon - Jelene, or Plastibase the hydrophilic organogels	Organogels
Preparation of Magmas and Gels	1. By freshly PRECIPITATING THE DISPERSED PHASE 2. By DIRECT HYDRATION in water .
GELLING AGENT obtained from seaweed, prepared products tasteless, odorless, yellowish-white colored fibrous powder -used as thickening agent in concentrations of 1 to 5% -swells in water to about 200 to 300 times its own weight without dissolving	Alginic acid
(GELLING AGENT) resins with high molecular weight -fluffy white powders with large bulk density (0.5 and 1% aqueous dispersion) allylpentaerythritol-cross-linked acrylic acid-based polymers modified with C10 to C30alkyl acrylates Example: Carbomers 910,934,934P,940 and 1342	Carbomer (Carbopol)
concentrations of 4 to 6% of medium viscosity can be used to produce gel; glycerin may be added to prevent drying; incompatible with alcohol GELLING AGENT	Carboxymethylcellulose
soluble in water at all temperature gelling agent	CMC sodium (Carboxymethyl Cellulose sodium)
can be used with other ingredients of similar refractive index to prepare transparent gels GELLING AGENT	Colloidal silicone dioxide
dispersed in hot water and cooled to form gels GELLING AGENT	Gelatin
concentrations of about 105 forms a firm thixotropic gel -material is inert and has few incompatibilities but is less used above pH 3.5	Magnesium aluminum silicate (Veegum)
long-chain substituted cellulose that can be used to form gels in concentration up to 5% - dispersed with high shear in about 1/3 of water gelling agent	Methylcellulose
mixture of 5% low molecular weight polyethylene and 95% mineral oil gelling agent	Plastibase (Jelene)
concentrations ranging from 15% to 50% to form gel 124 (L-44 grade), 188 (F-68 grade), 237 (F-87 grade), 338 (F-108 grade) and 407 (F-127 grade) types are freely soluble in water	Poloxamer (Pluronic)