Chemistry name: Hydroxypropyl methylcellulose; HPMC

CAS No.: 9004-65-3

EINECS No.: 618-389-6

Chemical formula:  C8H15O8-(C10H18O6 )n- C8H15O8

Molecular mass: N/A

Definition:

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EXCfiller®Hydroxypropyl methylcellulose is a semi-synthetic polymer formed by introducing methoxy and hydroxypropoxy groups through etherification reactions, with cellulose as its backbone. The hydroxyl groups in the cellulose repeating unit (C₆H₁₀O₅) are replaced. It is soluble in cold water (20-30°C) but insoluble in hot water (>50 °C, at which temperature it gels). Its aqueous solution is transparent and free from turbidity. It disperses and dissolves rapidly in solid beverages without precipitation. It performs stably across a pH range of 3-11 and is resistant to enzymatic degradation and oxidation. It provides thickening, suspension, emulsification, film formation, moisture retention and controlled release properties. It enhances the smoothness and texture of solid beverages while preventing ingredient separation. It serves as a microencapsulation shell or sustained-release carrier in dietary supplements.

■ Source

The core raw materials for EXCfiller®Hydroxypropyl methylcellulose are cellulose, etherifying agents and auxiliary materials. Sources of plant-based cellulose include softwood pulp (e.g. pine and spruce, with an α-cellulose content of ≥98%), broadleaf wood pulp (e.g. birch and poplar, with an α-cellulose content of ≥95%), and cotton linters (with an α-cellulose content of ≥99% and the highest purity, used for pharmaceutical-grade products). The α-cellulose content directly affects the efficiency of the etherification reaction and the purity of the final product. Etherification agents (functional group sources) include methoxylation reagents (e.g. chloromethane and dimethyl sulfate) and hydroxypropoxylation reagents (e.g. epichlorohydrin). Auxiliary materials include alkalising agents (such as sodium hydroxide for cellulose activation), water and isopropanol, which act as solvents to reduce etherification agent hydrolysis.

Particularities of EXCfiller®Hydroxypropyl methylcellulose:

Product Specifications:

EXCfiller®Hydroxypropyl methylcellulose is available in the following specification and contents:

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☑ EXCfiller®Hydroxypropyl methylcellulose (Methoxy 28.0-30.0%, Hydroxypropoxy 7.0-12.0%)

Product quality standards:

● USP, EP, BP, CP, Food grade, In-house

EXCfiller®Hydroxypropyl methylcellulose Applications:

The core applications of EXCfiller®Hydroxypropyl methylcellulose(HPMC) are based on its controllable viscosity, solubility in cold water, stability at different pH levels, film-forming properties and biocompatibility. In the pharmaceutical sector, HPMC is used for formulation shaping, controlled/sustained release and enhanced bioavailability. In the food sector, the focus is on texture modification, stability improvement and sensory optimisation. HPMC complies with global mainstream regulations, is non-allergenic and does not affect product nutritional profiles (it is sodium-free and contains no added sugar). It also exhibits excellent compatibility with ingredients such as whey protein, casein, vitamins and minerals.

In the pharmaceutical industry, 60% of the total demand for pharmaceutical-grade HPMC is accounted for by tablet excipients. When used as a binder, HPMC improves particle flowability and enhances tablet hardness, thereby preventing brittleness. The solution concentration is 2-5% (an aqueous solution that dissolves in cold water), with an addition rate of 2-8% of the total tablet mass. When used as a film coating material, it forms a uniform film that is moisture-proof, light-proof and flavour-masking. The coating solution concentration is 5-10%.When used as a sustained/controlled-release matrix material, it regulates the release rate of APIs (prolonging the duration of action). The addition rate is 20%-50% of the total tablet weight (adjusted based on release requirements). HPMC can serve as a capsule excipient, replacing gelatin in empty capsules to enhance stability in the presence of moisture and heat (ideal for vegetarian products). As a capsule filler binder, HPMC improves powder flowability and prevents stratification during filling. The addition rate is 1%-3% of the total filler powder mass (formulated as a 3% aqueous solution for granulation). Other applications include thickening, moisturising and stabilising emulsion systems in ointment/gel matrices, as well as in ophthalmic preparations (artificial tears), where it moisturises, thickens and prolongs ocular retention time. It can also be used as a microcapsule wall material for encapsulating APIs (masking odours and enhancing stability).

EXCfiller®Hydroxypropyl methylcellulose(HPMC) has many applications in the food industry. It is commonly used in solid beverages and dietary supplements as a thickening and suspending agent to prevent separation and sedimentation, for example in protein powders, probiotic powders and calcium, iron and zinc supplements. As a texture modifier, it improves smoothness and masks unpleasant flavours (e.g. vitamin C powder and plant-based protein drink powders). HPMC can also be used as a microencapsulation material to encapsulate functional ingredients such as DHA, EPA, lutein and probiotics. HPMC also serves as a rapid-dissolving dispersing agent to improve the solubility of poorly soluble vitamins and mineral powders.

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■ Production technology characteristics

The EXCfiller®Hydroxypropyl methylcellulose production process employs a three-stage approach: alkali activation, etherification and post-treatment. Batch production is the predominant method (suitable for multiple product specifications), while some enterprises utilise continuous processes (suitable for large-scale production of a single specification). The core reactions involve alkaline activation of cellulose and di-etherification.

Pulping wood pulp or cotton linters to a particle size of 20-40 mesh increases the material's specific surface area, thereby facilitating the alkylation reaction. This reaction (known as cellulose activation) causes the hydroxyl groups (-OH) on the cellulose chains to react with sodium hydroxide (NaOH), forming sodium cellulose salts. This breaks the hydrogen bonds between the cellulose molecules, thereby unfolding the molecular chains and creating active sites for the etherification reaction. Etherification (difunctional substitution) can be achieved through sequential methylation followed by hydroxypropylation, or through simultaneous etherification.

The simultaneous process is more efficient and better suited to industrial production. Post-treatment involves purification and modification, primarily comprising neutralisation, washing, drying and grinding.

☑ EXCfiller®Hydroxypropyl methylcellulose (Methoxy 19.0-24.0%, Hydroxypropoxy 4.0-12.0%)

☑ EXCfiller®Hydroxypropyl methylcellulose (Methoxy 16.5-20.0%, Hydroxypropoxy 23.0-32.0%)

☑ EXCfiller®Hydroxypropyl methylcellulose (Methoxy 27.0-30.0%, Hydroxypropoxy 4.0-7.5%)