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.
