Naproxen incorporated lipid emulsions. I. Formulation and stability studies.
BACKGROUND
Intravenous lipid emulsions stabilized with phospholipids have been an attractive alternative as vehicles for drug delivery, particularly for the parenteral administration of drugs with solubility problems.


METHODS
Naproxen (a poorly aqueous soluble non-steroidal anti-inflammatory agent) emulsions were formulated with different types of emulsifiers (soybean lecithin, synperonic PEF-127 and a 50:50 mixture of these). The stability of the various emulsion systems was evaluated at different temperatures (4, 25 and 40 degrees C) for a period of 6 months by measuring changes in pH, droplet size, viscosity and percentage oil separation. The percentage of naproxen incorporation and the degree of haemolysis induced by the different types of emulsion systems was also determined.


RESULTS
The emulsifier type showed a pronounced effect on the physicochemical properties of the emulsion systems, whereas storage temperature and time did not. Irrespective of emulsifier type, storage temperature and time, the percentage incorporation of naproxen in emulsions was between 80 and 100%. The degree of haemolysis induced by other emulsion components (dimethylsulfoxide (DMSO) and naproxen solution in DMSO) was about 10 times higher than that induced by emulsion systems.


CONCLUSIONS
Choice of emulsifier is the most important factor in the stability of the naproxen emulsions.
Pharmacy Faculty, Pharmaceutical Technology Department, Hacettepe University, Ankara, Turkey.
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Nasirideen
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Kaş
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Oner
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Alpar
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Hincal
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D004355:Drug Stability; D005079:Excipients / Q000737:chemistry; D005217:Fat Emulsions, Intravenous; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009288:Naproxen / Q000008:administration & dosage* / Q000737:chemistry; D010288:Parenteral Nutrition; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry; D013024:Soybean Oil / Q000737:chemistry; D013696:Temperature; D014783:Viscosity; D014810:Vitamin E / Q000737:chemistry
D000894:Anti-Inflammatory Agents, Non-Steroidal; D005079:Excipients; D005217:Fat Emulsions, Intravenous; D010713:Phosphatidylcholines; D014810:Vitamin E; D009288:Naproxen; D013024:Soybean Oil