Messi Biology states that magnesium hydroxide is a multifunctional pharmaceutical ingredient commonly used in tablet formulations. Characterized by its excellent antacid and laxative properties, it is widely applied in clinical medicine and the healthcare sector. Depending on its specific use in tablets, its functions can be primarily categorized into the following aspects:
1. Antacid Action
Magnesium hydroxide is a weakly alkaline substance. Upon entering the stomach, it undergoes a neutralization reaction with gastric acid (hydrochloric acid), rapidly alleviating discomfort symptoms such as heartburn, acid reflux, and stomach pain caused by excessive acidity.
- Gentle Effect: Compared to strong alkaline antacids like sodium bicarbonate, the neutralization process of magnesium hydroxide is milder and less likely to trigger “rebound gastric acid secretion.”
- Synergistic Formulations: It is frequently used in compound preparations containing aluminum hydroxide. This combination provides a synergistic antacid effect while mutually offsetting side effects—aluminum hydroxide tends to cause constipation, while magnesium hydroxide has a laxative effect.
Reaction Example:
Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O
2. Laxative Action
In higher dosages, magnesium hydroxide acts as a laxative. Because it is not easily absorbed by the intestines, it creates a hypertonic environment that draws water into the intestinal lumen. This softens the stool and stimulates bowel movements.
- Saline Laxative: It belongs to the class of saline laxatives, with an onset of action typically ranging from 6 to 12 hours. It is suitable for the adjunctive treatment of constipation.
- Mild Formulations: When combined with dietary fiber or plant extracts, it can be formulated into gentle, bowel-regulating tablets.
3. Magnesium Supplementation
Magnesium hydroxide is a vital source of elemental magnesium and is used as a magnesium fortifier in various nutritional supplement tablets.
- Addressing Deficiency: It is highly effective in treating symptoms caused by magnesium deficiency, such as muscle cramps, anxiety, and insomnia.
- Cost-Effectiveness: Compared to organic magnesium sources (such as magnesium glycinate or magnesium lactate), magnesium hydroxide tablets offer lower production costs and superior stability.
4. Synergistic Regulatory Role
In compound formulations, magnesium hydroxide can work synergistically with gastric mucosal protectants and prokinetic drugs to enhance comprehensive therapeutic effects.
- Combined Therapy: It is often used alongside H₂-receptor antagonists (like Ranitidine) or proton pump inhibitors (like Omeprazole) for the adjunctive treatment of gastric ulcers and gastroesophageal reflux disease (GERD).
- Drug Release Control: It can also influence drug release behavior by regulating the local pH value within the gastrointestinal tract, giving it significant application value in controlled-release tablet technology.