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Hydroxypropyl cellulose is a derivative of cellulose with both water solubility and organic solubility.
Hydroxypropyl cellulose is used as an excipient; a topical ophthalmic protectant and lubricant; a thickener, emulsifier, and stabilizer in cosmetic formulations; a sieving matrix for DNA separations by capillary and microchip electrophoresis; a leather consolidant used in book preservation; and a wood consolidant.
A cellulose ether with hydroxypropyl substitution.
CAS: 9004-64-2
MF: C3H7O*
MW: 59.08708
EINECS: 618-388-0
Synonyms
HYDROXYPROPYLCELLULOSE, M.W.60,000;oxypropylatedcellulose;pm50;pm50(polymer);syntheticvegetablegums;HYDROXYPROPYL CELLULOSE;2-Hydroxypropyl cellulose;Hydroxypropyl Cellulose (500 mg)
Hydroxypropyl cellulose is a derivative of cellulose being soluble in both water and organic acid.
Hydroxypropyl cellulose is excellent in trapping water and preventing water loss.
Hydroxypropyl cellulose can be used to treat diseases associated with insufficient tear production such as keratoconjunctivitis sicca, recurrent corneal erosions, decreased corneal sensitivity, and exposure and neuroparalytic keratitis.
Hydroxypropyl cellulose is also used as a lubricant of artificial eyes.
Hydroxypropyl cellulose can also be used as a thickener, an emulsion stabilizer and binder.
Moreover, Hydroxypropyl cellulose can be used as a sieving matrix for DNA separation through capillary and microchip electrophoresis.
Hydroxypropyl cellulose is also the major ingredient of Cellugel, which is used in book conservation.
Hydroxypropyl cellulose is a cellulose ether containing hydroxypropyl substitution.
Hydroxypropyl cellulose occurs as a white powder.
Hydroxypropyl cellulose is soluble in water and in certain organic solvents.
Hydroxypropyl cellulose may contain a suitable anticaking agent.
A cellulose ether with hydroxypropyl substitution.
Hydroxypropyl cellulose is biocompatible in nature and exhibits low critical solution temperature (LCST).
Hydroxypropyl cellulose has been reported to be prepared by reacting cellulose with alkali, producing alkali cellulose which is consecutively reacted with propylene oxide.
Hydroxypropyl cellulose is soluble in water at lower than RT.
Viscosity behaves inversely to rise in temperature.
In water, hydroxypropyl cellulose forms liquid crystals with many mesophases depending on concentration.
These mesophases include isotropic, anisotropic, nematic and cholesteric, the latter resulting in many colors such as violet, green and red.
Pharmaceutical applications include treatments for medical conditions such as dry eye syndrome (keratoconjunctivitis sicca), recurrent corneal erosions, decreased corneal sensitivity, exposure and neuroparalytic keratitis.
Hydroxypropyl cellulose is also used as a binder in tablets.
Hydroxypropyl cellulose is also used as a thickener, a binder and emulsion stabiliser in foods with E number E463.
Hydroxypropyl cellulose is used as a support matrix for DNA separations by capillary and microchip electrophoresis.
Cellulose, 2-hydroxypropyl ether, commonly referred to as hydroxypropyl cellulose (HPC), is a non-ionic, water-soluble derivative of cellulose.
Hydroxypropyl cellulose is produced by the etherification of cellulose with propylene oxide, resulting in the introduction of hydroxypropyl groups into the cellulose structure.
This modification enhances its solubility in water and organic solvents, making Hydroxypropyl cellulose useful in various applications.
Hydroxypropyl cellulose is characterized by its ability to form clear, viscous solutions, which makes it valuable as a thickening agent, film-forming agent, and stabilizer in pharmaceuticals, cosmetics, and food products.
Hydroxypropyl cellulose is also known for its biocompatibility and low toxicity, which further broadens its applicability in biomedical fields.
Additionally, hydroxypropyl cellulose exhibits thermoplastic properties, allowing it to be processed in various forms.
Hydroxypropyl cellulose's chemical stability and resistance to degradation under normal conditions contribute to its longevity in formulations.
Overall, Hydroxypropyl cellulose is a versatile polymer with significant utility across multiple industries due to its unique properties.
Hydroxypropyl cellulose Chemical Properties
Melting point: 371.06 °C
density: 0.5 g/mL at 25 °C (lit.)
refractive index: 1.5600
storage temp.: Room Temperature
solubility: polar oganic solvents: soluble
form: powder
color: White to light cream
PH Range: 5.0 - 8.5
PH: pH (20g/l, 25℃) : 5.0～7.5
Odor: at 100.00%. odorless
Water Solubility: Soluble in polar organic solvents, in water at room temperature.Soluble in water, methyl alcohol, ethyl alcohol and other organic solvents.
Merck: 14,4841
Stability: Stable. Incompatible with strong oxidizing agents. Combustible.
Cosmetics Ingredients Functions: BINDINGVISCOSITY CONTROLLINGSURFACTANT - EMULSIFYING FILM FORMING EMULSION STABILISING
Cosmetic Ingredient Review (CIR): Hydroxypropyl cellulose (9004-64-2)
InChI: InChI=1S/CH4/h1H4
InChIKey: VNWKTOKETHGBQD-UHFFFAOYSA-N
CAS DataBase Reference: 9004-64-2
EPA Substance Registry System: Hydroxypropyl cellulose (9004-64-2)
White or yellowish-white powder or granules, hygroscopic after drying.
Hydroxypropyl cellulose is a white to slightly yellow-colored, odorless and tasteless powder.
Chemistry
Hydroxypropyl cellulose is an ether of cellulose in which some of the hydroxyl groups in the repeating glucose units have been hydroxypropylated forming -OCH2CH(OH)CH3 groups using propylene oxide.
The average number of substituted hydroxyl groups per glucose unit is referred to as the degree of substitution (DS).
Complete substitution would provide a DS of 3.
Because the hydroxypropyl group added contains a hydroxyl group, this can also be etherified during preparation of HPC.
When this occurs, the number of moles of hydroxypropyl groups per glucose ring, moles of substitution (MS), can be higher than 3.
Because cellulose is very crystalline, HPC must have an MS about 4 in order to reach a good solubility in water.
Hydroxypropyl cellulose has a combination of hydrophobic and hydrophilic groups, so it has a lower critical solution temperature (LCST) at 45 °C.
At temperatures below the LCST, Hydroxypropyl cellulose is readily soluble in water; above the LCST, HPC is not soluble.
At the right concentrations, Hydroxypropyl cellulose forms liquid crystals and many mesophases.
Such mesophases include isotropic, anisotropic, nematic and cholesteric.
The last one gives many colors such as violet, green and red.
These colors are structural colors by nature and are also mechanochromic, meaning the HPC mesophase changes color when stress is applied.
Uses
Hydroxypropyl Cellulose is used in the synthesis of nanoparticle carriers for drug delivery.
As emulsifier, stabilizer, whipping aid, protective colloid, film former or thickener in foods; as binder in ceramics and glazes; in hair and cosmetic Preparations; in vacuum-formed containers and blow-molded bottles; as suspending agent in PVC polymerization. Pharmaceutic aid (tablet coating agent).
Hydroxypropyl Cellulose is a gum that is nonionic water-soluble cellulose, obtained from the reaction of alkali cellulose with propyl- ene oxide at high temperatures and pressures.
Hydroxypropyl cellulose is soluble in water below 40°c, is precipitated as a floc between 40°c and 45°c, and is insoluble above 45°c.
The precipitation is reversible with the origi- nal viscosity being restored upon cooling below 40°c and stirring.
Hydroxypropyl cellulose is used in whipped toppings as a stabilizing and foaming aid; in edible food coatings as a glaze and oil/oxygen barrier; and in fabri- cated foods as a binder.
typical usage level is 0.05–1.0%.
Hydroxypropyl cellulose is well established in the medical, pharmaceutical, and food industries as a widely applicable non-toxic, and cost-effective raw material.
Hydroxypropyl cellulose is commonly used as a thickener, emulsifier, stabilizer, binder and anti-caking agent.
Hydroxypropyl cellulose has E number E463.
In pharmaceuticals Hydroxypropyl cellulose is used as a binder in tablets, and is used variously within cosmetic formulations such as shampoos, conditioners, and lotions.
Lacrisert, manufactured by Aton Pharma, is a formulation of HPC used for artificial tears.
Hydroxypropyl cellulose is used to treat medical conditions characterized by insufficient tear production such as keratoconjunctivitis sicca, recurrent corneal erosions, decreased corneal sensitivity, exposure and neuroparalytic keratitis.
Hydroxypropyl cellulose is also used as a lubricant for artificial eyes.
Hydroxypropyl cellulose is used as a sieving matrix for DNA separations by capillary and microchip electrophoresis.
Hydroxypropyl cellulose is the main ingredient in Cellugel, described as a "safe, penetrating consolidant for leather book covers affected by red rot" by Preservation Solutions, and used in book conservation.
Due to its ability for structural color and mechanochromism at the right concentrations, it can also be utilised as an optical strain sensor, or as a more environmentally responsible color display technology driven mechanically.
Hydroxypropyl cellulose was used by conservators at the Firearms Museum at the Buffalo Bill Center of the West on the Forgotten Winchester, a Winchester Model 1873 lever-action centerfire rifle discovered in 2014 leaning against a tree in Great Basin National Park, Nevada.
Pharmaceutical Applications
Hydroxypropyl cellulose is widely used in oral and topical pharmaceutical formulations.
In oral products, hydroxypropyl cellulose is primarily used in tableting as a binder,film-coating,and extended-release-matrix former.
Concentrations of hydroxypropyl cellulose of 2–6% w/w may be used as a binder in either wet-granulation or dry, direct compression tableting processes.
Concentrations of 15–35% w/w of hydroxypropyl cellulose may be used to produce tablets with an extended drug release.
The release rate of a drug increases with decreasing viscosity of hydroxypropyl cellulose.
The addition of an anionic surfactant similarly increases the viscosity of hydroxypropyl cellulose and hence decreases the release rate of a drug.
Blends of hydroxypropyl cellulose and other cellulosic polymers have been used to improve wet granulation characteristics and tableting characteristics, as well as to achieve better control and manipulation of the rate of drug release.
As an alternative technology to wet granulation, dry granulation and direct compression of hydroxypropyl cellulose formulations have been reported to exhibit acceptable tableting and flow characteristics for application in extended-release matrix tablets.
Typically, a 5% w/w solution of hydroxypropyl cellulose may be used to film-coat tablets. Aqueous solutions containing hydroxypropyl cellulose together with an amount of methyl cellulose or ethanolic solutions have been used.
Stearic acid or palmitic acid may be added to ethanolic hydroxypropyl cellulose solutions as plasticizers.
Environmental concerns have limited the use of ethanol in film coating solutions.
Hydroxypropyl cellulose is also used in microencapsulation processes and as a thickening agent.
In topical formulations, hydroxypropyl cellulose is used in transdermal patches and ophthalmic preparations.
Hydroxypropyl cellulose is also used in cosmetics and in food products as an emulsifier and stabilizer.
Production Methods
A purified form of cellulose is reacted with sodium hydroxide to produce a swollen alkali cellulose that is chemically more reactive than untreated cellulose.
The alkali cellulose is then reacted with propylene oxide at elevated temperature and pressure.
The propylene oxide can be substituted on the cellulose through an ether linkage at the three reactive hydroxyls present on each anhydroglucose monomer unit of the cellulose chain.
Etherification takes place in such a way that hydroxypropyl substituent groups contain almost entirely secondary hydroxyls.
The secondary hydroxyl present in the side chain is available for further reaction with the propylene oxide, and ‘chaining-out’ may take place.
This results in the formation of side chains containing more than 1 mole of combined propylene oxide.
Manufacturing Process
The tertiary butanol, water and sodium hydroxide were mixed and the mixture cooled to 20°C.
The purified cotton linters were added to the mixture and aged at 20°C for one hour while stirring.
Excess liquid was filtered off the resulting alkali cellulose so that the resulting alkali cellulose filter cake weighed 3.08 parts.
This filter cake was broken up and slurried in the hexane, placed in a pressure vessel the pressure of which was increased to 100 psig with nitrogen, and then the pressure was vented to 5 psig.
The propylene oxide was added to the pressure vessel and then the pressure was increased to 25 psig with nitrogen.
The resulting charge was heated to 85°C in 30 minutes and then reacted at this temperature and 25 psig pressure for six hours.
The charge was cooled to 30°C.
the pressure vessel vented and 0.14 part of glacial acetic acid added.
The excess hexane was filtered off from the resulting hydroxypropyl cellulose product, the product was purified by washing with hot water (85°C to 95°C) and then dried at 130°C using a two-roll drum drier.
