Magnesium trisilicate mixture BP. Its physical characteristics and effectiveness as a prophylactic

Area of Science:

• Pharmaceutical Science
• Clinical Pharmacy

Background:

• Commercial magnesium trisilicate mixture BP compacts over time, especially with increased temperature.
• Compaction hinders redispersion into an effective suspension, impacting antacid efficacy.

Purpose of the Study:

• To evaluate the impact of storage on magnesium trisilicate antacid efficacy.
• To compare the effectiveness of commercially obtained versus freshly prepared antacids in anaesthetised patients.

Main Methods:

• Assessed the dispersibility of stored commercial magnesium trisilicate.
• Compared gastric aspirate pH in anaesthetised patients receiving commercial vs. hospital-prepared antacids.
• Measured magnesium concentration in gastric aspirates.

Main Results:

• Stored magnesium trisilicate became difficult to redisperse.
• Patients receiving commercial antacids had a higher incidence of gastric aspirates with pH < 3.0.
• Only one patient out of 131 receiving freshly prepared antacid was at risk.

Conclusions:

• Freshly prepared magnesium trisilicate antacids are more effective in preventing gastric acidity.
• Administering antacids shortly before anaesthesia (within 15 minutes) is crucial for patient safety.