High-Density Systems: Approaches for Gastroretentive drug delivery systems

Mechanism:

• Unlike floating systems, high-density systems are designed to sink to the bottom of the stomach and remain there for a prolonged period.

• They achieve this by having a density greater than the gastric fluids.

Components:

• These systems usually consist of drug cores coated with or incorporated into materials with a higher density (such as barium sulfate, zinc oxide, or other heavy materials) which ensures their prolonged gastric retention.

Applications:

I. For drugs that can cause gastric irritation:

• Some drugs, if present in the upper part of the stomach, might irritate the gastric mucosa.

• In such cases, a high-density system can be beneficial to retain the drug in the lower stomach, away from the sensitive mucosa.
  

II. For drugs acting locally in the stomach:

• Even though they are at the bottom, they ensure prolonged gastric retention and thus can be used for drugs acting in the stomach.

III. For drugs that have a narrow absorption window in the upper part of the intestine:

• Just as with floating systems, these systems can be advantageous for drugs that are primarily absorbed from the upper intestines by ensuring they are delivered to that region for a prolonged period.

Flowchart of high intensity system in GRDDS