Gels

Question 1

Sodium algenate

Answer 1

Use to produce ointment gels and percentages higher that]n 2.5%=firm gel

Question 2

Hydrogels 2 examples

Answer 2

Silica
Alumina
Sodium CMC
Methyl cellulose

Question 3

Organogels examples

Answer 3

Hydrocarbon type
Animal fats
Soaps and greases

Question 4

What is potralatum

Answer 4

Semi-solid pro-substance
Has crystalline and waxy fraction
((Stabilizer/thickener))

Question 5

Hydrophilic organogels

Answer 5

Polyethylene glycols: (carbowaxes)
75% soluble
Stable and feels like petrolatum
Jellies ::
Has high coherent matrix of liquid(usually water)

Question 6

———and——— are thickening agents to aqueous solutions that make cleaaar and unifooorm aqueous

Answer 6

Carboxymethyl cellulose and traganth

Question 7

A self despersed natural colloid

Answer 7

Acacia

Question 8

Gelling agent: ALGENIC acid

Answer 8

Tastless/odorless/from seaweed
Swell 200-300 times without dissolving by water
Yellowish white color
1%-5% thickening agent in gels
Procedure 30min in water and vigourosly mix
Ca++ salt is added for viscousty by cross-linking

Question 9

Bentonite magma (Suspending agent)

Answer 9

Thixotropic somewhat4%+
12 times swell
What
Alkaline environment and suspending is drastically decreased if reached less than 7 ph

Question 10

Aluminum hydroxide

Answer 10

Made of AlCl+Al(alum)=
Aluminum Oxide+Aluminum OH
Insoluble.             +precepitate  
—————————
Interfers with tetracylclens (trivalent cation)
That is why it should be staggered with tetracyclens 
Bioavalibility by chelating in GI tract
Avoid freezing and keep in tight container 
10ml dose (cause instepation)
MAO:coat inflammed gastric
Good for peptic ulcer and hyperacidity
Sweetners might be added

Question 11

Corbomer resins (carbopol)

Answer 11

1955 controlled release topical gels and oral suspension
High M.wt pentaerythritol -cross linked acrylic acid-
Modified with c10-30 alkyl acrylates
Fluffy white powders
Ph 1% water 2.5-3
When neutralizer is added it can grow 1k
20%alcohol we add NaOH or KOH
IN 50%alcohol we add triethanoleamine
0-80k cp viscosity

Question 12

Caromer 910,934,934p,940

Answer 12

910 low concentrations
934 highly effective in thick viscous
934p for oral use
940 the most efficient

Question 13

What is the effect of alcohol in carbomer gel

Answer 13

Decrease clarity and viscousty

Can be overcomed by the addition of carbomer

Question 14

What ph has highest clarity and maximum viscosty in carbomer

Answer 14

7 ph

But 4-11 is acceptable

Question 15

Milk of magnisia(opaque white)

Answer 15

Antacid 10 ph preparation
5ml to 10MeQ dose is enough15 TO EXCESSIVE HYPERACID CONDITIONS
7%to8.5% magnesium hydroxide
Made by reaction of NaOH+MgSO4
Then wash to remove sodium sulfate before adding water to needed volume
-it will separate on standing
Might cause diarrehea so we add aluminum hydroxide with it
30-60ml bedtime dose
Stored tight in 0-35c
Freezing cause in coarsening of disperse phase

Question 16

Why do we add 0.1 citric acid

Why do we add 0.05 flavoring oils? To milk of magnisium magma

Answer 16

1-because of high ph it might react with glass of container

2-because of its bitter taste

Question 17

Substance is said to be colloidal when size of parts?

Answer 17

1nm-0.5micrometer

Question 18

What is the differnces between colloidal dispersions and tru solutions

Answer 18

1-colloidal dispersion has larger dispersed phase particle size
W-colloids scatters the light unlike true solutions because of opaque particles

Question 19

Lyophilic colloids (starch water)

Answer 19

The dispersed phase interacts with medium
Higher stability/large organic molecules might be solvated and associated of dispersing phase
Disperse readily and easier to prepare
It has larger stability
More substance=more viscous=semisolid or solid gels

Question 20

Lyophobic colloids

inorganic particles generally

Answer 20

Small degree of attraction
Starch+alcohol
Do not spontaniously disperse
Does not greatly affect viscousty

Question 21

Association colloids

Answer 21

Amphiphilic

Both lyophilic and lyophobic

Question 22

How is the movement of particles in dispersing medium gels are prevented

Answer 22

By 3d dimentional network of particels and solvated macromolecules of dispersed phase

Question 23

Gels concentration

Answer 23

Less than q0% mostley

Usually between 0.5-2%

Question 24

Magma or milk is a ——— phase system

Answer 24

Two

Question 25

Imbibtion

Answer 25

Sucking liquid of gel without increasing volume ليفة

Question 26

Swelling

Answer 26

Sucking liquid by gel with increase of volume

Question 27

Thoxitropy

Answer 27

Gel-sol reversible substance without a change in volume or tempriture

Question 28

Xerogel

Answer 28

When all the liquid is out and only the framework is left

Question 29

Syneresis(instability)

Answer 29

When the dispersion phase bonds are so great that it shrinks gel dispersed medium and squeeze water out