What is Tablet coating?
Tablet coating is one of the oldest pharmaceutical processes still in existence. The coating is a process by which an essentially dry, outer layer of coating material is applied to the surface of a dosage form in order to confer specific benefits over an uncoated variety.
Either on the external surface of tablets or on materials dispensed within gelatin capsules. The coating serves a number of purposes:
- Protects the tablet (or the capsule contents) from stomach acids
- Protects the stomach lining from aggressive drugs such as enteric-coated aspirin
- Provides a delayed release of the medication
- Helps maintain the shape of the tablet
Ideally, the tablet should release the material gradually and the drug should be available for digestion beyond the stomach. The coating can be specially formulated to regulate how fast the tablet dissolves and where the active drugs are to be absorbed into the body after ingestion.
Many factors can affect the end-use properties of pharmaceutical tablets:
- Chemical composition
- Coating process
- Drying time
- Storage and environmental monitoring
Importance of Tablet Coating in Pharmaceutical
The application of a layer of coating material on the surface of tablets is a critical procedure in the pharmaceutical business. This coating offers a number of advantages, including enhancing tablet aesthetics, concealing undesirable tastes and smells, and preserving active components from degradation. This article will go over the significance of tablet coating in pharmaceuticals.
One of the main motivations for tablet coating is to improve tablet aesthetics. Tablets are available in a variety of forms, sizes, and colors. However, not all of them may be acceptable to patients visually. Some medications may appear unappealing, which may reduce patient compliance. This is where tablet coating can help. The addition of a layer of coating material to the tablets improves their look and makes them more aesthetically attractive to patients. As a result, patients are more likely to take their medicine as directed, which is crucial for attaining good treatment outcomes.
Another important advantage of tablet coating is that it masks undesirable tastes and smells. Some active pharmaceutical ingredients (APIs) have disagreeable flavors and scents, making it difficult for patients to swallow the pills. These unpleasant tastes and scents can even trigger nausea and vomiting in some situations, making it hard for patients to take their prescriptions. Tablet coating masks undesirable tastes and smells, making pills more appealing and simpler to take.
Tablet coating not only improves the look of tablets and masks bad tastes and smells, but it also protects the active contents from deterioration. Some APIs are susceptible to environmental conditions such as moisture, light, and oxygen, which can cause them to decay and lose potency. Tablet coating helps to protect the active ingredients from these environmental factors, ensuring that the medication remains stable and effective throughout its shelf life.
Tablet coating also helps to control the release of the active ingredients. Some medications require a specific release profile to achieve optimal therapeutic outcomes. For instance, some medications need to be released slowly over time, while others need to be released quickly. Tablet coating can be used to control the release of the active ingredients, ensuring that they are released at the right time and in the right amount. This is particularly important for medications that require a sustained release to maintain therapeutic efficacy.
Tablet coating is also important in the creation of modified-release formulations. Modified-release formulations are intended to release medication over a long period of time, generally many hours or days. This is especially crucial for drugs that must maintain therapeutic levels in the bloodstream at all times. Various coating processes, including as film coating, sugar coating, and enteric coating, can be used to create modified-release formulations.
Coating Process Design & Control
- Tablet coating takes place in a controlled atmosphere inside a perforated rotating drum. Angled baffles fitted into the drum and airflow inside the drum provide means of mixing the tablet bed. As a result, the tablets are lifted and turned from the sides into the center of the drum, exposing each tablet surface to an even amount of deposited/sprayed coating.
- The liquid spray coating is then dried onto the tablets by heated air drawn through the tablet bed from an inlet fan. The airflow is regulated for temperature and volume to provide controlled drying and extracting rates, and at the same time, maintaining the drum pressure slightly negative relative to the room in order to provide a completely isolated process atmosphere for the operator.
- Tablet coating equipment may include spray guns, coating pans, polishing pans, solution tanks, blenders and mixers, homogenizers, mills, peristaltic pumps, fans, steam jackets, exhaust and heating pipes, scales, and filters. Tablet coating processes may include sugar coating (any mixtures of purified water, cellulose derivatives, polyvinyl, gums, and sugar) or film coating (purified water, cellulose derivatives).
The coating process is usually a batch-driven task consisting of the following phases:
- Batch identification and Recipe selection (film or sugar coating)
- Loading/Dispensing (accurate dosing of all required raw materials)
- Warming
- Spraying (application and rolling are carried out simultaneously)
- Drying
- Cooling
- Unloading
A control system must therefore provide flexibility in the way in which accurate and repeatable control of the coating environment is achieved and will include the following features:
- Precise loop control with setpoint profile programming
- Recipe Management System for easy parameterization
- Sequential control for complex control strategies
- Secure collection of online data from the coating system for
- analysis and evidence
- Local operator display with clear graphics and controlled access to parameters
ALSO READ: Use of Binder in Tablet Formulation
Conclusion
Finally, tablet coating can also help to prevent cross-contamination. In the pharmaceutical industry, cross-contamination can occur when APIs from one batch of tablets contaminate another batch of tablets. This can have serious consequences, particularly in the case of potent or toxic APIs. Tablet coating can help to prevent cross-contamination by providing a physical barrier between different batches of tablets.
In Conclusion, tablet coating is a critical technique in the pharmaceutical sector that provides several advantages. It enhances tablet appearance, covers undesirable tastes and smells, prevents active ingredients from degradation, regulates active ingredient release, promotes the creation of modified-release formulations, and aids with cross-contamination prevention. These advantages are crucial for assuring pharmaceutical safety, effectiveness, and patient compliance. As a result, tablet coating is an important component of pharmaceutical production that should not be disregarded.
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