Sustained release tablets

Another form of coating is enteric coated tablets which are coated with a material which will dissolve in the intestine but remain intact in the stomach. Polymeric acid compounds have been used for this purpose with some success. This topic and the area of sustained release products has been discussed in more detail in other courses.

Benefits

• for short half-life drugs, sustained release can mean less frequent dosing and thus better compliance.
• reduce variations in plasma/blood levels for more consistent result.

Problems

• More complicated formulation, may be more erratic in result. A sustained release product may contain a larger dose, i.e. the dose for two or three (or more) 'normal' dosing intervals. A failure of the controlled release mechanism may result in release of a large toxic dose.
• more expensive technology

Types of products

• erosion tablets
• waxy matrix
  • matrix erodes or drug leaches from matrix
• coated pellets
  • different pellets (colors) have different release properties
• coated ion exchange
• osmotic pump
  • insoluble coat with small hole. Osmotic pressure pushes the drug out at a controlled rate.

Results - reduced side effects

Copyright 2001 David W.A. Bourne