CHAPTER-3POLYMER PROFILE
3.2 POLYMER PROFILE
HYDROXY PROPYL METHYL CELLULOSE K15 M
Structural formula:
Where R is H, CH3, or CH3CH [OH] CH2
Nonproprietary names
BP : Hypromellose
JP : Hydroxypropylmethylcellulose
PhEu : Hypromellosum
USP : Hypromellose
Synonyms: Benecel MHPC; E464; hydroxy propyl methylcellulose; HPMC;
methylcellulose propylene glycol ether; methyl hydroxypropylcellulose; Metolose:
Tylopor.
Chemical name: Cellulose hydroxy propyl methyl ether.
Functional category: Coating agent; film-former; rate-controlling polymer for
sustained release; stabilizing agent; suspending agent; tablet binder; viscosity- increasing
agent.
Description: Hypromellose is an odorless and tasteless, white or creamy-white
fibrous or granular powder.
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Typical properties
Acidity/alkalinity : pH = 5.5–8.0 for a 1% w/w aqueous solution.
3 3
Density [bulk] : 0.341 g/cm . Density [tapped] : 0.557 g/cm . Density
3
[true] : 1.326 g/cm .
Melting point : Browns at 190–200°C; chars at 225–230°C. Glass transition
temperature is 170–180°C.
Solubility : Soluble in cold water, forming a viscous colloidal solution;
practically insoluble in chloroform, ethanol [95%] and ether,but soluble in mixtures of
ethanol and dichloromethane, mixtures of methanol and dichloromethane, and mixtures of
water and alcohol.
Applications in pharmaceutical formulation or technology
Hypromellose is widely used in oral, ophthalmic and topical pharmaceutical formulations. In
oral products, hypromellose is primarily used as a tablet binder, in film-coating, and as a
matrix for use in extended-release tablet formulations. Concentration between 2% and 5%
w/w may be used as a binder in either wet or dry granulation processes. High-viscosity
grades may be used to retard the release of drugs from a matrix at levels of 10–80% w/w
in tablets and capsules. Depending upon the viscosity grade; concentration of 2–20% w/w
are used for film-forming solutions to film-coat tablets. Lower-viscosity grades are used in
aqueous film-coating solutions while higher-viscosity grades are used with organic solvents.
Viscosity [dynamic]
A wide range of viscosity types are commercially available [table 6 ]. Aqueous
solutions are most commonly prepared; Dichloromethane and ethanol
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mixtures may also be used to prepare viscous hypromellose solutions. Solutions prepared
using organic solvents tend to be more viscous; increasing concentration also produces more
viscous solutions.
Table. 6 Typical viscosity values for 2% [w/v] aqueous solutions of methocel,
viscosities measured at 20°C.
Nominal viscosity
Methocel product USP 28 designation
[mPa s]
Methocel K100 premium LVEP 2208 100
Methocel K4M premium 2208 4000
Methocel K15M premium 2208 15 000
Methocel K100M premium
2208 100 000
Methocel E4M premium
2910 4000
Methocel F50 premium 2906 50
Methocel E10M premium CR 2906 10 000
Methocel E3 premium LV 2906 3
Methocel E5 premium LV 2906 5
To prepare an aqueous solution, it is recommended that hypromellose is dispersed and
thoroughly hydrated in about 20–30% of the required amount of water. The water should be
vigorously stirred and heated to 80–90°C and then the remaining hypromellose should be added.
Then sufficient cold water should be added to produce the required volume.
Incompatibilities: Hypromellose is incompatible with some oxidizing agents.
Since it is nonionic, hypromellose will not complex with metallic salts or ionic organics to
form insoluble precipitates.
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Polyvinyl Alcohol
Nonproprietary Names: PhEur: Poly [vinylis acetas], USP: Polyvinyl alcohol
Synonyms: Alcotex; Gelvatol; Lemol; Mowiol; Polyvinol; PVA; Vinyl alcohol polymer,
PVOH, INS No. 1203
Chemical Names: Ethenol homopolymer
C.A.S. Number: 9002-89-5
Definition: Polyvinyl alcohol is a synthetic resin prepared by the polymerization of vinyl
acetate, followed by partial hydrolysis of the ester in the presence of an alkaline catalyst.
The physical characteristics of the product depend on the degree of polymerization and
the degree of hydrolysis.
Chemical Formula: [C2H3OR]n where R=H or COCH3 [randomly distributed]
Chemical Structure:
Empirical Formula: Weight range of approximately 20000-200000. [C2H4O]n. The
value of n for commercially available materials lies between 500 and 5000, equivalent to
a molecular weight.
Molecular Weight: 20000-200000.
Melting Point: 228°C for fully hydrolyzed grades; 180-190°C for partially hydrolysed
grades
Solubility: Soluble in water; slightly soluble in ethanol [95%]; insoluble in organic
solvents. Dissolution requires dispersion [wetting] of solid in water at room temperature
followed by heating the mixture to about 900°C for approximately 5 min mixing should
be continued while the heated solution is cooled to room temperature.
Description Polyvinyl alcohol is a water-soluble synthetic polymer. Polyvinyl alcohol
for food use is an odourless and tasteless, translucent, white or cream colored granular
powder. Typically a 5% solution of polyvinyl alcohol exhibits a pH in the range of 5.0 to
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6.5. It has degree of hydrolysis of 86.5 to 89%. Polyvinyl alcohol has excellent film
forming, emulsifying, and adhesive properties. PVA is an atactic material but exhibits
crystallinity as the hydroxyl groups are small enough to fit into the lattice without
disrupting it.
Functional Category: Coating agent; binder; sealing agent; lubricant; stabilizing agent;
viscosity-increasing agent and surface-finishing agent.
Applications: Polyvinyl alcohol is used as an emulsion polymerization aid, as protective
colloid, to make polyvinyl acetate dispersions. It is used primarily in topical
pharmaceutical and ophthalmic formulations. It is used as stabilizing agent for emulsions
[0.25-3.0% w/v]. Polyvinyl alcohol is also used as a viscosity-increasing agent for
viscous formulations such as ophthalmic products. It is used in artificial tears and contact
lens solutions for lubrication purposes, in sustained release formulations for oral
administration and in transdermal patches. Polyvinyl alcohol may be made into
microspheres when mixed with a glutaraldehyde solution. It is also used as emulsifying
agent. Polyvinyl alcohol is the raw material to make other polymers like Polyvinyl
nitrate, Polyvinyl acetals, Polyvinyl butyral, and Polyvinyl formal.
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