Sustained Release.

A sustained release coating is designed to release an active ingredient at a predetermined rate to maintain a constant dosage concentration for a specific period. The basic goal of sustained release coating is to achieve a steady state blood level that is both effective and nontoxic for an extended period.

The benefits of a sustained release dosage format include the reduction in blood level fluctuations of the administered drug, managing the disease better. The drug does not need to be administered as frequently, making it more convenient for the consumer and reducing the overall health care cost. Sustained release also means that drug accumulation is minimised when dosing chronic patients and the condition can be controlled more efficiently.

The types of materials used in coIating sustained release dosage forms include:

  • A mixture of waxes that are dissolved slowly or broken down in the gastrointestinal tract.
  • Shellac and zein polymers that remain intact until the PH contents become less acidic when entering the intestines
  • Ethyl cellulose which provides a membrane around the dosage form and remains intact throughout the gastrointestinal tract.
  • Acrylic resins which behave similarly to ethyl cellulose as a diffusion-controlled drug release coating material