Enteric coating and film coating are two common types of coating used in the medical industry. Although both are forms of coating, they have different functions and offer distinct advantages. Are you struggling to decide which coating to choose for your tablets? This article provides an introduction to the differences between the two.
What Is Enteric Coating?
Enteric coating is a special type of coating applied to the surface of a tablet. It does not dissolve in the stomach, but dissolves only once it reaches the intestines.
This design has two advantages. It protects the stomach from irritation caused by the medication. It also helps more precise drug release and protects the medication from being broken down in the acidic environment. It also helps extend the medication’s shelf life.
Enteric coating dissolves only after reaching the intestines, so it takes longer for the medication to take effect. For manufacturers, enteric coatings require stricter manufacturing standards and entail higher production costs.
What Is Film Coating?
Film coating is the application of a thin polymer coating to the surface of a tablet, which is another method of protecting tablets. Unlike enteric coating, film coating dissolves in the stomach.
Film coating forms a physical barrier between the tablet and the external environment, protecting the medication from moisture, light, and oxidation. They can be made to look more appealing, and their smooth surface can also improve the swallowing experience.
Film coating does not protect the stomach from drug irritation. And it cannot ensure targeted delivery.
Summary of the Difference Between Enteric Coating and Film Coating
Core Objectives and Functions
The main function of an enteric coating is to protect tablets so they can safely pass through the stomach and dissolve until they reach the intestines. It is designed to prevent the drug from being broken down in the stomach or the stomach from being irritated by the drug.
Film coating serves a variety of purposes. You can achieve different functional emphases by adjusting the formula. The main functions include smoothing the surface of the tablets to make it easier to swallow, masking the bitter taste, protecting the medication from moisture, light, and oxidation, and improving the tablets’ appearance to improve brand identification.
Ingredients
Enteric coatings are typically made from acid-resistant polymers, such as cellulose acetate phthalate (CAP) and methacrylate copolymers.
Film coating typically uses water-soluble polymers, such as hydroxypropyl methylcellulose (HPMC). There are also plasticizers and colorants.
Appearance
Film-coated tablets have a smooth, glossy surface, brighter colors, and can also be printed with a logo.
Enteric-coated tablets can also be colored. But the appearance is usually a secondary
consideration compared with functional performance. They tend to have a duller appearance.
Cost and Production Complexity
Since even the smallest crack can cause the drug to be released in the stomach, the enteric coating must remain intact, which places higher demands on the manufacturing process. It requires multiple layers of sealing, resulting in a slower production speed.
The production of film coatings is usually faster and simpler. Because it does not require the same strict control over humidity and temperature in the production environment as enteric coating does. The number of coating layers is also fewer than that of enteric coatings.
Application Types
Enteric coatings are primarily used for medications that can irritate the stomach or are sensitive to stomach acid. Examples include aspirin, probiotics, and enzyme supplements.
Film coating is suitable for a wide range of immediate-release medications and has no specific restrictions. Common examples of film-coated medications include Lipitor, ibuprofen, and metformin.
Manufacturing Process
The main production process for film coating is placing the tablets into a coating pan. A spray system evenly applies a polymer solution to the surface of the tumbling tablets, and hot air rapidly dries them to form a coating.
The process for enteric coating is similar to that for film coating, but it requires a slower spray rate and more precise temperature control. Sometimes even need multiple spray passes or the application of a sealing coating. It ensures that the coating is complete and has no pores.
Equipment Selection
If you will use film coatings, it is best to prioritize production speed. You can choose a standard anti-bearding spray system with a high spray rate. A drying system with high airflow and a basic automated control system is suitable. Equipment capacity can be selected based on your needs.
If you will use enteric coatings, it is especially important to ensure that your equipment can provide precise control. We recommend selecting a high-precision spray system. The drying system should be able to precisely control temperature and humidity. For high-cost drugs, it is advisable to produce smaller batches.
FAQ
Are Enteric Coatings and Film Coatings Plastic?
Coating materials are not plastics in the conventional sense, such as PP or PE. The polymers used in medicine coatings are food-grade materials that undergo strict safety assessments. These materials are considered safe for oral use and are either excreted
unchanged or processed by the body without causing harm.
The plasticizers added to film coatings and enteric coatings (such as triethyl citrate) are also widely recognized as safe by the medical industry.
Can the Same Equipment Be Used for Film Coating and Enteric Coating?
The processes for film coating and enteric coating are similar, and the same tablet coater can be used for both. However, the tablet coater must be able to precisely control, with a range of adjustable parameters that can meet the requirements of both film coating and enteric coating.
What Are the Different Types of Film Coatings?
Based on the solvent system, film coatings are primarily categorized as water-based or solvent-based. Water-based coatings are the mainstream option now. They are safer and more environmentally friendly. Solvent-based coatings use organic solvents and are primarily used for drugs that are extremely sensitive to moisture. They pose a safety risk due to their flammability and are not very environmentally friendly.
Are Film-Coated Tablets Safer Than Uncoated Tablets?
Film-coated tablets are not necessarily safer than uncoated tablets. The safety of a coating depends on the specific material used. You should consult the relevant local regulations to ensure the safety of the material before selecting coating materials.
If a medication is stored for an extended period, coated tablets may be safer than uncoated tablets, as the coating helps protect the medication from degradation.
Can the Enteric Coating Be Broken or Crushed? How about Film Coating?
Enteric coatings cannot be broken or crushed. This will cause the medication to be released prematurely in the stomach, which can irritate the stomach or reduce the drug’s effectiveness.
Not all film-coated tablets can be broken. If the tablet has a score line, it can usually be broken in half. If there is no score line, it most likely cannot be broken. We recommend that you consult a healthcare professional before doing so.
Final Thoughts
Choosing the right tablet coating type is the first step toward success, and selecting a reliable partner is the key. Pilotech is a tablet coating machine manufacturer. We have over twenty years of production experience and will offer you excellent product quality. We also have equipment such as spray dryers and granulators. Welcome to contact us!