Hydroxypropyl cellulose Chemische Eigenschaften,Einsatz,Produktion Methoden
S-S?tze Betriebsanweisung:
S24/25:Berührung mit den Augen und der Haut vermeiden.
Beschreibung
Hydroxypropyl cellulose is a cellulose ether containing hydroxypropyl substitution. It occurs as a white powder. It is soluble in
water and in certain organic solvents. It may contain a suitable
anticaking agent.
Chemische Eigenschaften
Hydroxypropyl cellulose is a white to slightly yellow-colored,
odorless and tasteless powder.
Verwenden
Hydroxypropyl Cellulose is used in the synthesis of nanoparticle carriers for drug delivery.
Definition
A cellulose ether with hydroxypropyl substitution.
Vorbereitung Methode
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. Thisresults in the formation of side chains containing more than 1 mole
of combined propylene oxide.
Allgemeine Beschreibung
Hydroxypropyl cellulose (HPC) is biocompatible in nature and exhibits low critical solution temperature (LCST). It has been reported to be prepared by reacting cellulose with alkali, producing alkali cellulose which is consecutively reacted with propylene oxide. HPC is soluble in water at lower than RT. Viscosity behaves inversely to rise in temperature.
Sicherheit(Safety)
Hydroxypropyl cellulose is widely used as an excipient in oral and
topical pharmaceutical formulations. It is also used extensively in
cosmetics and food products.
Hydroxypropyl cellulose is generally regarded as an essentially
nontoxic and nonirritant material. It is not absorbed from the
gastrointestinal tract and is fully recovered in feces after oral
administration in rats. It does not exhibit skin irritation or skin
sensitization. However, the use of hydroxypropyl cellulose as a solid
ocular insert has been associated with rare reports of discomfort or
irritation, including hypersensitivity and edema of the eyelids.
Adverse reactions to hydroxypropyl cellulose are rare. However, it
has been reported that a single patient developed contact dermatitis
due to hydroxypropyl cellulose in a transdermal estradiol patch.
The WHO has specified an acceptable daily intake for
hydroxypropyl cellulose of up to 1500 mg/kg body-weight.
Excessive consumption of hydroxypropyl cellulose may have a
laxative effect.
LD50 (rat, IV): 0.25 g/kg
LD50 (rat, oral): 10.2 g/kg
Lager
Hydroxypropyl cellulose powder is a stable material, although it is
hygroscopic after drying.
Aqueous solutions of hydroxypropyl cellulose are stable at pH
6.0–8.0, with the viscosity of solutions being relatively unaffected.
However, at low pH aqueous solutions may undergo acid
hydrolysis, resulting in chain scission and hence a decrease in
solution viscosity. The rate of hydrolysis increases with increasing
temperature and hydrogen ion concentration. At high pH, alkalicatalyzed
oxidation may degrade the polymer and result in a
decrease in viscosity of solutions. This degradation can occur owing
to the presence of dissolved oxygen or oxidizing agents in a
solution.
Increasing temperature causes the viscosity of aqueous solutions
to decrease gradually until the viscosity drops suddenly at about
45°C owing to the limited solubility of hydroxypropyl cellulose.
However, this process is reversible and on cooling the original
viscosity is restored.
The high level of substitution of hydroxypropyl cellulose
improves the resistance of the polymer to degradation by molds
and bacteria. However, aqueous solutions are susceptible to
degradation under severe conditions and a viscosity decrease may
occur. Certain enzymes produced by microbial action will degrade
hydroxypropyl cellulose in solution. Therefore, for prolonged
storage, an antimicrobial preservative should be added to aqueous
solutions. Solutions of hydroxypropyl cellulose in organic solvents
do not generally require preservatives.
Ultraviolet light will also degrade hydroxypropyl cellulose and
aqueous solutions may therefore decrease slightly in viscosity if
exposed to light for several months.
Aqueous hydroxypropyl cellulose solutions have optimum
stability when the pH is maintained at 6.0–8.0, and also when the
solution is protected from light, heat, and the action of microorganisms.
Hydroxypropyl cellulose powder should be stored in a wellclosed
container in a cool, dry place.
Inkompatibilit?ten
Hydroxypropyl cellulose in solution demonstrates some incompatibility
with substituted phenol derivatives, such as methylparaben
and propylparaben. The presence of anionic polymers may increase
the viscosity of hydroxypropyl cellulose solutions.
The compatibility of hydroxypropyl cellulose with inorganic
salts varies depending upon the salt and its concentration. Hydroxypropyl cellulose may not tolerate high concentrations
of other dissolved materials.
The balance of the hydrophilic–lipophilic properties of the
polymer, which are required for dual solubility, reduces its ability to
hydrate with water and it therefore tends to be salted out in the
presence of high concentrations of other dissolved materials.
The precipitation temperature of hydroxypropyl cellulose is
lower in the presence of relatively high concentrations of other
dissolved materials that compete for the water in the system;
Regulatory Status
GRAS listed. Accepted for use as a food additive in Europe.
Included in the FDA Inactive Ingredients Database (oral capsules
and tablets; topical and transdermal preparations). Included in
nonparenteral medicines licensed in the UK. Included in the
Canadian List of Acceptable Non-medicinal Ingredients.
Hydroxypropyl cellulose Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
