Hydroxypropyl methylcellulose (HPMC) is a commonly used semi-synthetic cellulose ether derivative with significant application value in pharmaceutical preparations. Due to its excellent safety, stability, and multifunctional properties, HPMC is widely used in tablets, capsules, sustained-release and controlled-release formulations, and topical preparations. It not only serves as a pharmaceutical excipient but also plays a key role in drug release regulation and improving formulation performance.

1. Applications in Tablets

HPMC is a commonly used binder and film-forming agent in tablet production. During the granulation process, it improves inter-powder adhesion, enhancing tablet hardness and disintegration resistance. Furthermore, the thin film formed by HPMC on the tablet surface exhibits excellent mechanical strength and abrasion resistance, making it suitable as a coating material to mask unpleasant odors and bitter tastes, thereby improving patient compliance. Furthermore, HPMC films provide moisture and oxidation protection for drugs, extending their stability and shelf life.

2. Applications in Capsules

HPMC can be used as the primary material for hard or soft capsule shells. Compared to traditional gelatin capsules, HPMC capsules offer advantages such as being less susceptible to temperature and humidity, being free of animal ingredients, and being suitable for vegetarians. Furthermore, HPMC capsules exhibit good solubility and rapidly release drugs in the gastrointestinal tract, helping to improve drug absorption. In recent years, with the increasing demand for plant-based capsules, HPMC capsules have become a major trend in the pharmaceutical industry.

3. Controlled-Release and Sustained-Release Formulations

HPMC is particularly widely used in sustained-release and controlled-release formulations. Its hydrophilicity and gelling properties enable it to rapidly swell and form a gel layer upon contact with water, thereby controlling the drug release rate. By adjusting the degree of substitution, viscosity grade, and dosage of HPMC, it is possible to achieve slow drug release over varying time periods, helping to maintain stable blood drug concentrations, reduce dosing frequency, and improve efficacy and patient compliance. This property makes HPMC a key excipient for oral sustained-release and controlled-release tablets.

4. Suspension and Emulsion Stabilizers

In oral liquid formulations, HPMC is commonly used as a suspending agent and thickener. It increases the viscosity of the solution, preventing drug particle sedimentation, thereby maintaining uniform drug distribution and ensuring accurate dosing. In emulsions, HPMC also acts as a stabilizer, improving the stability of the emulsion system and preventing phase separation.

5. Topical and Ophthalmic Preparations

Due to its excellent biocompatibility and moisturizing properties, HPMC is widely used in topical medications and ophthalmic preparations. In eye drops, HPMC increases viscosity, prolongs the drug’s residence time on the ocular surface, and thus improves drug bioavailability. It also provides lubrication and moisturizing properties, making it a common adjunctive treatment for dry eye. In topical gels, creams, and patches, HPMC acts as a film-forming agent and thickener, improving spreadability and drug release characteristics.

6. Drug Protection and Stabilization

HPMC also plays a protective role in pharmaceuticals. It acts as a barrier to light-sensitive and easily oxidized drugs, reducing the risk of drug degradation during storage and use. Furthermore, in solid dispersion preparations, HPMC can serve as a carrier to improve the solubility and bioavailability of poorly soluble drugs, enhancing their efficacy.

HPMC plays a crucial role in the pharmaceutical field. HPMC is widely used in the pharmaceutical industry for its safety, stability, and diverse functionality, whether in tablets, capsules, sustained-release formulations, eye drops, or topical medications. With the advancement of formulation technology, the application prospects of HPMC will be even broader, especially in plant-derived pharmaceutical excipients and intelligent controlled-release drug systems, where it is expected to play a greater role.