Encapsulation of doxorubicin into liposomes by a freeze-thawing method using buffer solution

Area of Science:

• Pharmaceutical Sciences
• Drug Delivery Systems
• Lipid Nanoparticles

Background:

• Liposomes are widely used nanocarriers for drug delivery.
• Doxorubicin is a potent chemotherapeutic agent with limited solubility.
• Encapsulation efficiency (EN%) of drugs into liposomes is crucial for therapeutic efficacy.

Purpose of the Study:

• To investigate the influence of buffer solution properties on doxorubicin encapsulation into liposomes using freeze-thawing.
• To elucidate the mechanism behind pH-dependent doxorubicin encapsulation.

Main Methods:

• Preparation of drug-free liposomes by hydration.
• Mixing liposomes with doxorubicin dissolved in various buffer solutions.
• Subjecting the mixture to freeze-thawing cycles.
• Analyzing doxorubicin encapsulation percentage (EN%) and liposome particle size.

Main Results:

• Encapsulation efficiency (EN%) varied significantly based on the buffer solution's pH.
• Doxorubicin encapsulation was enhanced at buffer pH levels above 7.
• Approximately 60% doxorubicin encapsulation was achieved after the first freeze-thaw cycle.
• EN% increased with repeated freeze-thaw cycles.
• Addition of sugar affected both doxorubicin encapsulation and liposome particle size.

Conclusions:

• The pH difference between freezing and thawing is the primary driver for doxorubicin encapsulation into liposomes via freeze-thawing.
• Optimizing buffer pH is critical for maximizing doxorubicin loading into liposomes.
• Freeze-thaw cycles and sugar additives represent key parameters influencing liposomal doxorubicin formulation.