[Study of phenothiazine binding to membranes by the fluorescent probe method]

Area of Science:

• Biochemistry
• Membrane Biophysics
• Pharmacology

Background:

• Phenothiazines are a class of drugs with diverse pharmacological effects.
• Understanding drug-membrane interactions is crucial for drug development and predicting efficacy.
• Model phospholipid membranes provide a simplified system to study these interactions.

Purpose of the Study:

• To investigate the binding of chlorpromazine, etaperazine, and triftazine to model phospholipid membranes.
• To characterize the interaction mechanism and localization of these phenothiazine drugs within the membrane.
• To compare the binding affinities and effects of different phenothiazine molecules on membrane properties.

Main Methods:

• Utilized a 3-methoxybenzanthrone (MBA) fluorescent probe.
• Employed fluorescence spectroscopy to monitor MBA fluorescence extinction upon drug binding.
• Analyzed the heterogeneous binding patterns of chlorpromazine.

Main Results:

• All tested phenothiazines (chlorpromazine, etaperazine, triftazine) interacted with the model membranes.
• Phenothiazine molecules localized in the superficial layer of the membrane.
• MBA fluorescence extinction indicated drug binding, with varying efficiencies: chlorpromazine < etaperazine < triftazine.
• Chlorpromazine exhibited heterogeneous binding, suggesting at least two distinct interaction modes.

Conclusions:

• Phenothiazines effectively bind to phospholipid membranes, influencing their structure.
• The binding affinity and mechanism differ among phenothiazine drugs.
• The study provides insights into the biophysical interactions of phenothiazines with biological membranes.