Coating is the unit operation referring to the application of an outer layer of coating material onto the dry surface of the drug dosage form. This coating material provides not only easier product identification, but even advances the drug’s pharmacokinetic properties by modifying drug release: ensuring that the drug reaches its target site and provides enough concentration in the body for a prolonged period of time.
Coating can be applied to a wide range of oral solid dosage forms including tablets, capsules, multiparticulates and drug crystals. The most commonly coated dosage form, however, are the tablets, followed by coated multiparticulates which have gained popularity since.
Reasons for coating pharmaceutical dosage forms vary, but the more common reasons are to:
- Mask the taste of unpleasant tasting APIs and excipients.
- Improve product appearance
- Aid in the rapid identification of product by the manufacturer, the pharmacist, and the patient.
Provide modified-release characteristics for an efficient drug delivery rate and ensure it reaches target site.
- Improve product stability by protecting the API from light and moisture during storage.
- Film coating
A very popular technique, owing to a number of coated products in the market. Film coating involves the deposition, usually by a spraying method, of a thin polymer film to surround the tablet, capsule or multiparticulate core.
- Sugar coating
Since the late 19th century, this traditional process has been used in the pharmaceutical industry, and it closely resembles the process for coating sweets. This unit operation involves the continuous application of sucrose-based coating onto tablet cores via coating equipment. In this process, water evaporates from the syrup to leave a thick sugar layer around each tablet. Mostly, sugar coats are highly coloured and shiny.
- Compression coating
In the preparation of modified release products, use and popularity of this process has greatly increased. It is essentially a dry process which involves the compression of granules around a preformed tablet core using specially designed tableting equipment.
Esco Pharma’s experienced team of designers and engineers can help in designing a completely integrated manufacturing equipment: from the granulation, drying, blending, and even coating process of pharmaceutical manufacturing. All of this to ensure the protection of operators, product, and the environment from possible cross-contamination or unwanted occupational exposure.
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