Major HPMC Uses in Pharmaceuticals Introduced

We will talk about the major hpmc uses in pharmaceuticals in this article, which will be introduced in detail in three sections: what HPMC is, what HPMC’s advantages are as well as the five main applications of HPMC in pharmaceuticals, through which you will have a systematical knowledge about HPMC. 

What Is HPMC?

Before talking about the major hpmc uses in Pharmaceuticals, we will have a brief introduction to HPMC. HPMC, with full name hydroxypropyl methylcellulose, also called Hypromellose, is one of non-toxic cellulose mixed ethers. Due to its strong stability and high safety without toxic side effects, HPMC is widely applied in the pharmaceuticals and food industries. 

What Are the Advantages of HPMC?

How HPMC is used in pharmaceuticals is closely based on its advantages. In this article, let’s have the basic knowledge about HPMC’s advantageous properties firstly, thus you will have a better understanding of its wide application in the pharmaceutical industry. 

1. HPMC, with excellent cold-water solubility and no-charge in aqueous solution, forms colloids with water molecules, resulting in strong stability, which therefore allows it seamless compatibility with other excipients.

2. HPMC has excellent safety with no toxic side effects, as supported by toxicity data revealing its non-metabolization within the body.

3. HPMC products’ viscosity varies according to different concentrations, molecular weight, and temperature, hence the good properties in film-forming, thickening, emulsifying, suspending capabilities, and so on. 

Based on the above great properties, HPMC is popularly utilized in pharmaceutical products. 

What Are the Major HPMC Uses in Pharmaceuticals?

After the clarification about the HPMC’s conception and properties in the former parts of this article, you may have basic knowledge about it, which will be greatly useful for you to learn about the main uses of this ingredient. In the following part, we will have a further introduction to HPMC’s main application in pharmaceuticals according to two aspects: its different properties and usage in different pharmaceutical types. 

1. HPMC can be used as film coating material in pharmaceuticals

With excellent film-formation property, the film formed by this ingredient provides proper strength, good permeability as well as nice anti-embrittlement. Besides, the film also remains stable under heat, light, and certain humidity conditions, plus its good solubility in organic solvents and water, it has less negative effect in tablet disintegration and dissolution, therefore it is in common use as a gastric coating material, offering effective and superior thin-film coating outcomes. 

There is a research literature about Gentamicin proving the functions of HPMC: Due to the strong hygroscopic nature, the table quality of Gentamicin tablet is unstable and easily gives the results of chipping and discoloration, and afterwards the short storage life, about only one year. However, when HPMC is applied in Gentamicin’s film coating, the result is greatly changed. 

2. HPMC can be used as capsule shell material in pharmaceuticals

When employed in making capsule shells, HPMC shows distinct advantages compared with gelatin-based capsules: firstly, it can overcome the cross linking problems existing on gelatin-based capsules; secondly, HPMC has only 4%-5% water content, much lower than gelatin-based capsules’ 12.5%-17.5%, so HPMC capsule shell is more suitable to be employed for those contents with high moisture absorbability and sensibility, which surely guarantees a longer shelf life of this kind of products. 

3. HPMC can be used as binder and disintegrating agent on tablet HPMC

HPMC can be used as binder and disintegrating agent on tablet HPMC, classified into E/K/F series based on differences in methoxy and hydroxypropyl content, and finds diverse applications in the pharmaceutical industry. The E3-E50 series, characterized by low viscosity, serves as a valuable binder in tablet formulations. HPMC, as a binder solution, significantly reduces the drug's contact angle, enhancing wetting properties and enabling a substantial increase in drug dissolution and release rates. 

Studies have demonstrated the successful substitution of HPMC for conventional binders, in ibuprofen formulations, leading to improved drug solubility and overall tablet quality.

Furthermore, HPMC offers two additional advantages as a binder. Firstly, its low hygroscopicity enhances tablet stability during storage. Excessive moisture absorption can lead to issues like caking, deliquescence, and polymorphic changes, affecting drug content and release. Research indicates that HPMC, along with other cellulose-based binders like HPC and EC, has a balanced water content of around 5% or less, making it advantageous compared to PVP and CMC-Na, which have higher water absorption capacities, around 18% and 15% respectively. 

Secondly, HPMC's lower peroxide content contributes to enhanced drug stability compared with another binder PVP. Reduced peroxide levels prevent direct reactions with oxidation-prone drugs, mitigating the formation of free radicals.

4. HPMC can be used as suspending and stabilizing agent 

HPMC enhances the viscosity of liquid dispersion media, reduces solid-liquid interfacial tension, and stabilizes suspensions, preventing particle aggregation and delaying sedimentation, hence wide usage as suspending agent for eye drops making. Studies regarding the suspending agents of acyclovir eye drops have identified a superior formulation using 0.05% HPMC 4000 in combination with 0.05% Hyaluronic Acid (HA) as the suspending agent, leading to smaller, more uniform particles.

5. HPMC can be used as hydrophilic skeletal material in sustained-release tablets

HPMC, as a hydrophilic skeletal material, finds widespread application in sustained-release tablets. HPMC K-series is the type employed commonly. When the viscosity of HPMC is larger, the viscosity of the formed gel layers is higher, which leads to the water-insoluble drugs releasing slowly from the skeleton. By adjusting the ratio of HPMC to the drug, the release rate can be modulated; higher HPMC content results in slower drug release. However, excessive HPMC usage may increase tablet weight, affecting patient compliance. Studies suggest that selecting appropriate HPMC viscosities and using combinations of HPMC in different viscosities can achieve good drug release result at different time points.

Conclusion:

With its excellent physicochemical properties, HPMC finds extensive applications in the pharmaceutical industry, including serving as a film-coating material, capsule shell component, binder disintegrating agent onto tablet, suspending and stabilizing agent, hydrophilic skeletal material in sustained-release tablets, and so on. Without doubt, ongoing research is expected to expand its utility and promote its multifaceted development across various fields.