Liposomes: a new approach to gold therapy?

Area of Science:

• Pharmacology
• Biotechnology
• Drug Delivery Systems

Background:

• Gold sodium thiomalate (GST) is a gold salt used in treating rheumatoid arthritis.
• Conventional administration of GST can lead to significant renal toxicity and rapid clearance.
• Novel drug delivery systems are needed to improve GST's therapeutic index.

Purpose of the Study:

• To investigate the potential of egg phosphatidyl choline vesicles as a carrier for parenteral administration of gold sodium thiomalate (GST).
• To evaluate the pharmacokinetic profile and tissue distribution of GST encapsulated in liposomes compared to free GST.

Main Methods:

• Gold sodium thiomalate (GST) was encapsulated in egg phosphatidyl choline and cholesterol vesicles.
• Vesicle stability and leakage were assessed at room temperature.
• The biodistribution and pharmacokinetic parameters of encapsulated GST were compared to free GST following intravenous administration in a preclinical model.

Main Results:

• Encapsulation of GST in egg phosphatidyl choline vesicles resulted in negligible leakage at room temperature, allowing for storage up to 6 days.
• Intravenous administration of encapsulated GST demonstrated delayed blood clearance compared to free GST.
• Enhanced uptake of encapsulated GST was observed in the liver and spleen, with reduced uptake by the kidneys.
• A significant reduction in 24-hour urine excretion of encapsulated GST was noted.
• Encapsulated GST showed enhanced accumulation in inflamed tissues compared to free GST.

Conclusions:

• Egg phosphatidyl choline vesicles demonstrate excellent stability for GST encapsulation and storage.
• Liposomal encapsulation of GST alters its pharmacokinetic profile, leading to favorable biodistribution.
• These findings suggest that egg phosphatidyl choline vesicles are a promising carrier for parenteral delivery of GST, potentially improving efficacy and reducing toxicity.