Mechanism:
Gastroadhesive or bioadhesive systems adhere to the gastric mucosal surface, ensuring prolonged retention.
These systems use polymers that can adhere to the mucus layer in the stomach, hence prolonging the gastric residence time of the dosage form.
Components:
I. Bioadhesive Polymers:
These are the key components in gastroadhesive systems. Commonly used polymers include hydroxypropyl methylcellulose (HPMC), chitosan, poly (acrylic acid), carbopol, and alginate
II. Drug Reservoir:
This contains the therapeutic entity which is then released in a controlled manner.
Types:
I. Bioadhesive Tablets:
These are conventional tablet forms that have been integrated with bioadhesive polymers.
II. Bioadhesive Films or Patches:
Thin films or patches that can adhere to the gastric mucosa.
III. Micro- and Nanoparticles:
These are smaller entities that have bioadhesive properties, ensuring their adhesion to the gastric mucosa.
Applications:
I. Localized Drug Action:
Drugs that act locally on the gastric mucosa, such as for ulcers, can be administered via bioadhesive systems.
II. Drugs with a narrow absorption window:
Drugs that are primarily absorbed in the stomach or upper small intestine benefit from these systems as they ensure the drug remains in the desired location for an extended period.
III. Improved Bioavailability:
By prolonging the drug's residence in the stomach or upper intestine, the bioavailability of certain drugs can be enhanced.
