Stability studies with amphotericin B and amphotericin B methyl ester.

Area of Science:

• Pharmaceutical Chemistry
• Drug Stability
• Antifungal Agents

Background:

• Amphotericin B is a critical antifungal medication.
• Understanding the stability of amphotericin B and its derivatives is crucial for formulation and storage.
• Amphotericin B methyl ester is a derivative with potential therapeutic applications.

Purpose of the Study:

• To compare the stability of amphotericin B and its methyl ester derivative in solid and solution states.
• To investigate the impact of pH and temperature on the stability of amphotericin B methyl ester salts.

Main Methods:

• Comparative stability studies of amphotericin B and amphotericin B methyl ester free base in solid form.
• Stability assessment of amphotericin B methyl ester acid salts under various conditions.
• Solution stability studies of both compounds at different pH and temperatures.

Main Results:

• Solid-state stability was comparable between amphotericin B and its methyl ester free base.
• Amphotericin B methyl ester acid salts demonstrated lower stability compared to the parent compound under identical storage.
• In solution, amphotericin B was generally more stable than its methyl ester salts.
• At pH 6.0 and 5°C, amphotericin B methyl ester salts exhibited stability similar to amphotericin B.

Conclusions:

• The stability of amphotericin B and its methyl ester is influenced by their chemical form (free base vs. salt) and environmental conditions.
• Specific conditions (pH 6.0, 5°C) can enhance the stability of amphotericin B methyl ester salts in solution, approaching that of amphotericin B.