Studies on molecular interactions between nalidixic acid and liposomes

Area of Science:

• Lipid-drug interactions
• Photochemistry
• Nanomedicine

Background:

• Liposomes are crucial drug delivery systems.
• Nalidixic acid sodium salt (NANa) is an antibiotic.
• Understanding drug-liposome interactions is vital for effective drug delivery.

Purpose of the Study:

• To investigate the interaction between NANa and liposomes composed of DPPC and DOPC.
• To evaluate the impact of UV-B irradiation on these interactions and radical formation.
• To characterize liposome stability and phase transition modifications.

Main Methods:

• Differential scanning calorimetry (DSC) for thermal analysis.
• Electron paramagnetic resonance (EPR) spectroscopy for molecular interactions and radical kinetics.
• Dynamic light scattering (DLS) for liposome size distribution.
• Spectrophotometry for entrapment efficiency determination.

Main Results:

• NANa primarily interacts with the head groups of liposome lipids.
• UV-B irradiation induces free radical formation, with effects extending beyond the head group region.
• Liposome phase transition parameters are altered by NANa, influenced by the dioleoyl-phosphatidylcholine content.

Conclusions:

• NANa interacts with liposome lipid head groups, and UV-B irradiation induces free radicals.
• The observed effects on liposome properties are dependent on lipid composition, particularly DOPC content.
• These findings provide insights into the stability and behavior of NANa-loaded liposomes under UV-B exposure.