When a pharmaceutical substance is precisely delivered over a lengthy period of time to provide the intended therapeutic effect, the term “controlled drug release” is used. It entails creating medication dosage forms in such a way that the drug releases under controlled conditions and in accordance with a preset release profile. The key method for achieving controlled medication release is tablet coating.
The physical and chemical qualities of dosage forms can be enhanced through a multistep process called tablet coating. Additionally, it can disguise taste, regulate drug release patterns, and lessen gastrointestinal adverse effects.
For medications that need certain release schedules, such as sustained release, extended release, or delayed release, controlled drug release is essential. Medical experts can improve the pharmacokinetics of a medicine, improve patient compliance, and lessen side effects by managing the drug’s release.
Tablet Coating: How Important Is It?
The tablet coating is essential for regulated medication release. Drug degradation is prevented and the correct release pattern is made possible by the coating, which serves as a barrier between the drug and its surroundings. Tablet coating also adds mechanical strength, enhances aesthetics, and hides the drug’s disagreeable taste or odor.
Various Techniques for Tablet Coating
To ensure regulated drug release, a variety of coating techniques are used in the pharmaceutical production process. The drug’s unique needs and the desired release profile influence the coating process selection. Three frequently used coating methods are listed below:
1. Candied Coating
One of the earliest coating processes is sugar coating. The tablet is covered in several coatings, such as sugar syrup, coloring additives, and polishing agents. The tablet’s finish is smooth, glossy, and attractive thanks to this approach.
2. Movie Coating
The process of film coating involves covering the tablet’s surface with a thin polymer film. This method allows for more accurate rate control of medication release since the polymer film can be designed to do so. For sustained-release formulations, film-coated tablets are frequently employed.
3. Biological Coating
When a medicine needs to be protected from the stomach’s acidic environment, enteric coating is applied. Although the coating is impervious to gastric juices, it degrades in the intestine’s alkaline environment. The drug will be released in the desired area of the gastrointestinal tract thanks to enteric-coated tablets.
Factors Affecting the Release of Controlled Drugs
The regulated release of medications from coated tablets is influenced by a number of factors. Optimizing medication release profiles requires a thorough understanding of these elements. The following elements are important:
1. Composition of Coating
The medication release profile is substantially impacted by the coating material selection. The release properties of various polymers might vary depending on their hydrophilic or hydrophobic nature, sensitivity to pH, or permeability.
2. Layer Thickness
The coating layer’s thickness has a direct bearing on how quickly drugs are released. While thinner coatings may result in a speedier release, thicker coatings often release the drug more slowly.
3. Sensitivity to pH
pH-sensitive enteric coatings disintegrate at particular pH levels. This characteristic enables targeted drug release in the desired gastrointestinal tract location.
4. Rate of Dissolution
The medication release profile is impacted by the coating’s rate of breakdown. Rapidly dissolving coatings swiftly release the medication, whereas slowly dissolving coatings produce prolonged release.
Benefits of Tablet Coating for Drug Release under Control
In order to achieve regulated drug release, tablet coating offers various benefits. Let’s look at a few of them:
1. Better Stability
By shielding tablets from environmental elements including moisture, light, and oxygen, coatings improve the stability and shelf life of pharmaceuticals.
2. Enhancing Bioavailability
The coating can regulate the drug’s rate of release, enhancing absorption and bioavailability. It makes certain that the medication is released in the ideal area for maximum absorption.
3. Specific Drug Delivery
For efficient treatment of illnesses like inflammatory bowel disease or peptic ulcers, coating techniques like enteric coating offer targeted drug delivery to certain parts of the gastrointestinal tract.
4. less negative effects
The coating can reduce the occurrence of negative effects linked to high medication concentrations by regulating the drug’s rate of release. It aids in keeping the medication level constant and within the therapeutic range.