Naproxen incorporated lipid emulsions. I. Formulation and stability studies

Area of Science:

• Pharmaceutical Sciences
• Drug Delivery Systems
• Physical Chemistry

Background:

• Phospholipid-stabilized intravenous lipid emulsions are promising for parenteral drug delivery, especially for poorly soluble compounds.
• Naproxen, a non-steroidal anti-inflammatory drug, presents solubility challenges for effective parenteral administration.

Purpose of the Study:

• To evaluate the impact of different emulsifiers on the stability and characteristics of naproxen-loaded lipid emulsions.
• To assess the influence of storage temperature and time on these emulsion systems.

Main Methods:

• Formulation of naproxen emulsions using soybean lecithin, synperonic PEF-127, or a mixture.
• Stability assessment over six months at various temperatures (4, 25, 40°C) by measuring pH, droplet size, viscosity, and oil separation.
• Determination of naproxen incorporation efficiency and induced hemolysis.

Main Results:

• Emulsifier type significantly influenced emulsion physicochemical properties, while storage temperature and time had minimal impact.
• Naproxen incorporation ranged from 80-100% across all tested conditions.
• Emulsion systems induced significantly less hemolysis compared to naproxen in dimethyl sulfoxide (DMSO).

Conclusions:

• The selection of the emulsifier is the critical determinant for the stability of naproxen-loaded lipid emulsions.
• These developed emulsions demonstrate good naproxen incorporation and reduced hemolytic potential, suggesting suitability for parenteral drug delivery.