Oral Delivery of Proteins and Peptides: Concepts and Applications - Challenges in Delivery of Therapeutic Genomics and Proteomics - page 498

Bioadhesive Materials Properties Characteristics

l Also incompatible with the substituted phenolic
derivatives, such as methyl and propyl parahydroxy
benzoate
l Granulating and film-coating agent for tablet
l Thickening agent, emulsion stabilizer, suspending
agent in oral and topical solution or suspension

Hydroxypropylmethyl
cellulose—HPMC (cellulose
2-hydroxypropylmethyl ether)
empirical formula: C 8 H 15 O 6 -
(C 10 H 18 O 6 ) n -C 8 H 15 O 5

l Methocel E5, E15, E50, E4M, F50, F4M, K100,
K4M, K15M, K100M.
l MW 8.6  10 4
l  E15-15 cps, E4M-400 cps and K4M-4000 cps
(2% aqueous solution.)
l  Cold water, mixtures of methylene chloride and
isopropylalcohol
l Insoluble in alcohol, chloroform, and ether
l Odorless, tasteless, white or creamy white fibrous
or granular powder

l Mixed alkyl hydroxyalkyl cellulosic ether
l Suspending, viscosity-increasing and film forming
agent
l Tablet binder and adhesive ointment ingredient
l E grades generally suitable as film formers, while K
grades are used as thickeners
l Stable when dry
l Solutions stable at pH 3.0 to 11.0
l Incompatible to extreme pH conditions and oxidizing
materials

Hydroxyethyl cellulose nonionic
polymer made by swelling
cellulose with NaOH and treating
with ethylene oxide

l Available in grades ranging from 2 to 800,000 `cps
at 2%
l Light tan or cream-to-white powder, odorless and
tasteless; may contain suitable anticaking agents
l  0.6 g/ml
l pH 6-8.5
l  in hot or cold water and gives a clear, colorless
solution

l Solutions are pseudoplastic and show a reversible
decrease in viscosity at elevated temperatures
l HEC solutions lacking yield value
l Solutions show only a fair tolerance with water-
miscible solvents (10-30% of solution weight).
l Compatible with most water-soluble gums and resins
l Synergistic with CMC (carboxy methyl cellulose) and
sodium alginate
l Susceptible to bacterial and enzymatic degradation
l Polyvalent inorganic salts will salt out HEC at lower
concentrations than monovalent salts
l Shows good viscosity stability over the pH 2-12 range.
l Used as a suspending or viscosity builder