There are various tablet coating types. If you’re still confused about how to choose the suitable tablet coating method for your pharmaceutical project, you’ve come to the right place. I will introduce four main tablet coating types to help you protect active pharmaceutical ingredients and control drug release.
What is Tablet Coating?
Tablet coating applies a layer of a specific substance to the tablet surface to change its appearance and taste, and control its pharmacological effects. In simple terms, tablet coating acts like a “coat” for the tablet, which enhances its appearance while performing specific functions.
In the pharmaceutical manufacturing process, tablet coating improves the appearance of the medication and masks its bitter taste, which makes it more palatable to consumers. In addition, it helps protect the stability of the medication and control its release.
Main Types of Tablet Coating
Film Coating
Film coating typically involves spraying a thin polymer film onto the surface of a tablet. The resulting film coated tablets have a smooth surface and uniform color, and you can print patterns or words on them. In addition, the process is cost-effective and highly efficient, which is suitable for most common pills and health supplements.
However, please note that uneven film application may result in color variations, which could affect the appearance of your pharmaceutical product. Film coating places high demands on equipment temperature and application uniformity, so you must strictly follow the operating procedures.
Sugar Coating
Sugar coating utilizes a sugar solution to coat tablets, creating a thick, sweet outer layer. Sugar coated tablets are not only thick and glossy, but also have a good taste. You can produce tablets in various colors with a high gloss finish. It is suitable for children’s medications, health supplements with high taste requirements, and traditional medicines that require a sugar-coated effect.
Sugar coating also has some drawbacks: it is time-consuming, relatively expensive, and it is sensitive to humidity in the production environment. You should balance the pros and cons before you make the decision.
Enteric Coating
Enteric coating applies a layer of acid-resistant material to the surface of a tablet, preventing the drug from being released in the stomach and instead allowing it to be released in the intestines. This type of coating, which precisely controls the release site of the drug, protects the drug from being damaged by stomach acid while reducing irritation to the stomach.
This coating method is often used for antibiotics, probiotics, and drugs gentle on the stomach. When using this type of coating, you need to precisely control the pH and wall thickness, as enteric coatings place high demands on the precision of the coating equipment.
Other Functional Coating
Functional coating utilizes special materials or multi-layer structures to form a coating layer on the surface of tablets, enabling your drug to be released at the designed rate and location, achieving drug sustained-release or segmented release.
Functional coating usually employs high-molecular controlled-release materials, such as ethyl cellulose, carboxymethyl cellulose, acrylic resin, etc. A single tablet can have 2-3 layers or even more, with each layer playing a different function. This coating process requires you to precisely control the spraying thickness and strictly control the solvent and drying conditions.
Due to their complex processes, large equipment requirements, and high costs, functional coatings are commonly used in high-end pharmaceutical products and multi-layer compound formulations.
Comparison of Different Tablet Coating Types
| Coating Type | Cost | Processing Time | Technical Difficulty | Key Features | Main Applications |
| Film Coating | Low | Short | Medium | Improve appearance, mask taste | Medicines, health supplements |
| Sugar Coating | High | Long | Low
|
Change the texture and color | Children’s medications, traditional medicines |
| Enteric Coating | Medium | Medium | High
|
Enteric-coated, stomach-protective | Antibiotics, probiotics |
| Functional Coating | High | Medium | Very high | Controlled-release, sustained-release | High-end formulations, compound medications |
How to Choose the Appropriate Tablet Coating Type?
Product Features
Some medicines are sensitive to acid, alkaline substances, light and humidity. Therefore, for medicines that are sensitive to stomach acid, enteric coated tablets are suitable. For bitter tablets, you can choose film coated or sugar coated tablets to mask and improve the taste.
Furthermore, if you need to manufacture small tablets or irregular-shaped tablets, film coating can realize your requirements better. For large tablets, sugar coating and functional coating may be more stable.
Functional Requirements
When you are choosing the suitable coating type, you should make the decision by your functional requirements.
To realize controlled or sustained-release efficacy, you should select functional coatings or sustained-release coatings. If you need the medicine to be released in the intestine, then you should choose enteric-coated materials. However, as you want to improve the appearance and taste, film coatings or sugar coatings would be more appropriate for pharmaceutical projects.
Balance Costs and Efficiency
The film coating has low cost and fast production speed, which is suitable for large-scale pharmaceutical production. For high value-added products, you had better choose functional coating or multi-layer coating. Although the cost is higher, its market value is also higher.
Equipment Support
The type, capacity and automation level of your factory’s tablet coating machine are also important factors. High-precision coating machines are suitable for functional or enteric coating, while traditional unperforated coating machines are more suitable for sugar coating.
When your pharmaceutical production volume is large, it is recommended that you choose a large-capacity coating equipment to ensure efficiency.
FAQ
What are the Common Problems During the Tablet Coating Process?
During the tablet coating process, you may encounter problems such as uneven coating, tablet adhesion, cracking, powder shedding or unstable controlled release. Choose Pilotech and we can provide you with reliable tablet coating solutions.
Will the Tablet Coating Affect the Absorption of the Drug?
A properly designed coating will not affect the absorption effect of the drug. On the contrary, like enteric coatings and controlled-release coatings can optimize drug release and efficacy.
Why Does Sugar Coating Have a Longer Processing Time?
The sugar coating layer is thick, requiring multiple spraying and drying processes. Therefore, the processing time for sugar coating is longer than that for film coating. However, its coating effect is shiny and the taste is also good.
Can Film Coating and Enteric Coating be Used Simultaneously?
Yes. You can first apply an enteric coating, then cover it with a film to improve its appearance while still maintaining the enteric function. But you need to precisely control the coating process.
Is Multi-Layer Functional Coating Better than Single-Layer Coating?
Multi-layer functional coating can achieve segmented release or controlled release effects, but its process is complex and the cost is high. You’d better design the number of coating layers according to your product requirements so as to best achieve the drug efficacy.
Final Thoughts
Different tablet coating types are suitable for different drugs. You should make a comprehensive judgment to select the most suitable coating method for your pharmaceutical project. If you are looking for a reliable tablet coating partner, don’t hesitate to contact Pilotech for professional solutions. Pilotech looks forward to cooperating with you!
