Description

Dexlansoprazole is a proton pump inhibitor (PPI) that is the R-enantiomer of the racemic compound lansoprazole. The term “EC Pellets” refers to its pharmaceutical formulation as enteric-coated (EC) pellets. These pellets are designed with a unique dual delayed-release system: some pellets are coated to release the drug at a higher pH (e.g., in the proximal small intestine) and others are coated to release the drug at a lower pH (e.g., in the distal small intestine). This formulation is designed to provide prolonged acid suppression over a 24-hour period.

Indications

Dexlansoprazole is used to treat various acid-related conditions. Its indications are similar to other PPIs but its dual-release formulation makes it particularly effective for:

• Healing of all grades of erosive esophagitis: It is used for the short-term healing of damage to the esophagus caused by gastroesophageal reflux disease (GERD).

• Maintenance of healed erosive esophagitis: It is indicated for the long-term maintenance of healing in patients who have completed therapy.

• Symptomatic non-erosive GERD: It is used to treat heartburn associated with GERD in patients without erosive esophagitis.

Mechanism of Action

Dexlansoprazole’s mechanism of action is two-fold: it involves the drug’s inherent ability to inhibit acid production and the unique pharmacokinetic advantage of its dual-release formulation.

1. Inhibition of the Proton Pump:
   • Dexlansoprazole is a prodrug that is absorbed into the bloodstream from the small intestine.
   • It then travels to the parietal cells in the stomach lining, where it is activated in the acidic environment of the secretory canaliculi.
   • The activated form of dexlansoprazole irreversibly binds to the H+/K+-ATPase enzyme, also known as the “proton pump.”

• • This pump is the final step in the gastric acid secretion process. By permanently blocking it, dexlansoprazole effectively stops the production of gastric acid.

2. Dual Delayed-Release Formulation:
   • The drug’s pellets are manufactured with two distinct enteric coatings.
   • The first coating dissolves at a higher pH, allowing for an initial release of the drug in the proximal small intestine within a few hours. This provides rapid acid suppression.
   • The second coating requires a lower pH to dissolve, resulting in a second, later release of the drug in the distal small intestine, approximately 4 to 5 hours after the first release.

• • This dual-release mechanism creates two separate plasma concentration peaks, which provides a longer duration of effective acid suppression and maintains a high gastric pH for a longer period compared to a single-release PPI. This can be particularly beneficial for patients with nocturnal GERD or those with incomplete symptom control on a single-release PPI.