Stability of melphalan solutions during preparation and storage

Area of Science:

• Pharmacology
• Analytical Chemistry
• Biochemistry

Background:

• Melphalan is a key chemotherapeutic agent.
• Accurate in vitro chemosensitivity assays require stable drug solutions.
• Understanding melphalan stability under various conditions is critical for reliable experimental results.

Purpose of the Study:

• To investigate the stability of melphalan solutions under conditions relevant to in vitro chemosensitivity assays.
• To determine optimal storage and handling conditions for melphalan.
• To quantify melphalan degradation rates in different media and temperatures.

Main Methods:

• A stability-indicating high-performance liquid chromatographic (HPLC) assay was employed.
• Melphalan solutions were subjected to various storage temperatures (-35°C to room temperature), freeze-thaw cycles, and filtration.
• Degradation kinetics were analyzed using Arrhenius plots.

Main Results:

• Melphalan exhibited 30% greater stability in normal saline compared to Dulbecco's phosphate-buffered saline.
• At 20 µg/mL in normal saline, melphalan's half-life (t0.95) was 1.5 hours at room temperature and 20 hours at 5°C.
• Significant degradation (<5%) was not observed after 7 months of storage at -20°C or -35°C, or after multiple freeze-thaw cycles.
• The half-life of melphalan in RPMI medium with 10% FBS at 37°C was 1.13 ± 0.10 hours.

Conclusions:

• Melphalan solutions are most stable when stored at low temperatures (e.g., -20°C) for extended periods (up to 12 months).
• Handling melphalan at temperatures above 5°C should be minimized to prevent rapid degradation.
• The stability of melphalan in various media and under different conditions provides essential data for optimizing in vitro chemosensitivity assay protocols.