4. Sources:
1.wood pulp
2.Chemical cotton
Methylcellulose is chemically obtained by treatment of cotton with alkali and
methylation of the alkali cellulose with methyl chloride under pressure to
convert hydroxyl group into methyl ether groups
5. Characteristics:
• Methylcellulose occures as white,
• fibrous powder.
• It is colorless, odourless and tasteless.
• It swells in water and forms a clear to
• opaiescent , viscous, colloidal solution in cold water.
• It is insoluble in hot water , alcohol and water.
• Ab aqeous solution is best prepared by dispersing the granules in hot water with stirring and chilling
to +5^0 c.
• The solution is then stable at room temperature
6. Solubility:
• The solubility of methylcellulose is dependent upon the degree of
substitution. Commercial methyl cellulose has a methoxyl content of29%.
Clear film may be casted from the aqeous solution
7. Phamaceutical uses of methylcellulose
1. Solutions containing methyl cellulose
are used as substitute for tears or
saliva if the natural production of
these fluids is disturbed.
2.It is also used for
A) constipation,
B)diverticulosis,(the formation of abnormal pouches in the bowel wall. )
C)hemorrhoids (swollen veins in your lower rectum)
D)irritable bowel syndrome etc.
8. • 3. Methylcellulose is also used to
increase the viscosity and to
stabilize lotions, suspensions ,
pastes , ophthalmic preparations
and some ointments
• 4. As a hydrophilic colloid and
laxative for chronic constipation.
9. CELLULOSE ACETATE
Other names:
• Acetate rayon
• Partially acetylated cellulose
• The anhydroglucose unit is the fundamental repeating structure of cellulose and
has three hydroxyl groups which can react to form acetate esters
10. Source:
• All cellulose acetates are obtained by treating cellulose with acetic
anhydride at various temperatures for different lengths of time to produce
amorphous white solid
• material in granular ,flake or powder
• form ,from which fibres maybe
• produced by extrusion.
11. Characteristics
• Cellulose acetate resembles with viscous rayon in its appearance.
• Commercial products do not have sharp melting points.
• The filaments are highly lustrous, grooved and slightly twisted
• Solubility
• Solubility is affected by the acetyl value; the triacetate is insoluble in water ,
alcohol, ether but soluble in glacial acetic acid.
• The penta acetate is insoluble in water but soluble in alcohol
12. Uses in Pharmacy
• Cellulose acetate rayon is used to manufacture rubber and celluloid
substitutes, non flammable photographic and cinema films, airplane dopes,
varnishes and laquers, filaments, phonograph records etc.
• Cellulose acetate is used for constructing semipermeable coating on tablets,
especially in osmotic pump-type tablets and microparticles for controlled
release of drugs.
