PHARMACEUTICAL FILM COATING

ORAL SOLID DOSAGE FORMS

PHARMACEUTICAL FILM COATING

ORAL SOLID DOSAGE FORMS

Film coating is a process widely used in the pharmaceutical industry that involves applying a thin, uniform layer of a polymer covering the entire surface of an oral solid dosage form, such as a tablet or granule.
Film coatings can be classified in many ways, but one of the most common is based on the drug delivery system. According to this classification, film coatings are divided into immediate-release film coatings and modified-release film coatings:

  • Immediate-release film coatings, also called non-functional film coatings or conventional film coatings, are commonly used to modify product appearance, ease of swallowing, stability, or taste masking. The coatings do not have a measurable effect on the biopharmaceutical properties of the coated dosage forms, only on appearance, durability, or organoleptic characteristics.
  • Modified-release film coatings, or functional film coatings, are used to modify the drug release characteristics. Depending on how they do it, modified-release film coatings can be further classified as delayed-release coatings (eg, gastro-resistant / enteric coating) or extended-release coatings.
Pharmaceutical Film Coating Process for Tablets and Granules | STE Tecpharm

 

The film-coating formulation combines four key ingredients:

  • A film-forming polymer, which provides the mechanical strength of the film. The most widely used polymers in non-functional film coating are cellulose derivatives such as hypromellose.

  • Plasticizers, used to improve the flexibility of the film formed and prevent it from cracking or breaking. They work by weakening the attraction between the polymer molecules to make the film more malleable.
  • Coloring agents, which increase opacity, protect from light, and color the film.
  • Fillers, which can be added to reduce tack and improve slip, or to adjust the content of insoluble materials in the coating composition.

MAIN REASONS FOR FILM COATING

Beyond the aesthetic dimension, the coating film plays a major role in the therapeutic adherence and functional properties of tablets:

  • Long-life lasting: protects the product from light, moisture, and oxidation.
  • Appearance improvement: especially when the active ingredient is colored or produces an inhomogeneous color.
  • Ingestion facilitating: a smoothed surface makes the oral form easier to swallow.
  • Taste and odors improvement: mask the taste and the odors associated with the active ingredients.
  • Controlled release: delay the release of the active ingredient, or target different sites of the gastrointestinal tract.
This film coating process can be carried out by different methods depending on the oral solid dosage form to be coated: tablet or granule.

TABLET FILM COATING

In the film coating of tablets, the tablets are placed in a perforated pan that rotates with a slow and continuous movement.

The coating solution is applied from spray nozzles located into the drum and above the bed of tablets, dispensing the coating solution based on the desired end result.

Thanks to the rotating movement of the drum and to baffles located inside it, the tablets are mixed and gently displaced within the drum, facilitating their exposure to the sprayed coating solution.

A controlled air stream crosses the interior of the drum and the bed of tablets assisting in the correct distribution of the sprayed coating solution while performing the drying process.

The end result is a full and homogeneous film-coated tablet.

GRANULE FILM COATING

In the case of granule film coating, the granules are mixed with gentle movement and combined with the spraying of the coating solution.

The most common equipment for this process is a Fluid Bed Coater, which can also perform the previous granulation process.

The Fluid Bed Coater works on the principle of fluidization. In this fluidization process, hot air is introduced, with defined pressure and flow, through a perforated bed on which the granules rest. These granules are lifted from the bottom and suspended in a stream of air (fluidized state).

The movement of the product in a fluidized state is combined with the spraying of a coating solution. Spraying is done from the bottom and can be vertical through tubular (Wurster system) or tangential rotation (tangential spray).

The heat transfer takes place by direct contact between the coated granules and the hot gases, which dries the solution into a thin and homogeneous film around the granule.

Coating Process of Pharmaceutical Granules by Fluid Bed Coater | STE Tecpharm

MAIN PIECES OF EQUIPMENT FOR FILM COATING

Tablet Coater OPTIMA. Perforated coating pan for tablets and pellets | STE Tecpharm

TABLET COATER

FOR PHARMACEUTICAL TABLETS

perforated coating pan designed for the film coating of tablets, suitable in aqueous and organic coatings, for the pharmaceutical industry

Fluidized Bed Dryer for drying, granulation and coating | STE Tecpharm

FLUIDIZED BED COATER

COATING AND DRYING OF GRANULES

Designed for 3 different processes:
■ Drying of wet granulate.
■ Top drive granulation.
■ Bottom spray coating for micro granules.
Standard equipment resistant to 10 bar pressure. Parameters control: Temperature, air flow, vacuum and process time.

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    SUCCESS OF OUR STE REMOTE FAT SYSTEM

    SUCCESS OF OUR STE REMOTE FAT SYSTEM

    Last week we successfully performed the Remote Factory Acceptance Test (FAT) of an OPTIMA Tablet Coater for a major pharmaceutical customer from Algeria.