Comparison of the effect of anti-hyperlipidemic drugs from different groups on the phase profile of liposomal membrane–a fluorescence anisotropy study

Abstract

The study compares the effect of incorporation of three different groups of anti-hyperlipidemic drugs, namely niacin, simvastatin, and fenofibrate on the phase profile of liposomal membranes of dipalmitoylphosphatidylcholine (DPPC). The fluorescence anisotropy studies, using 1,6-diphenyl-1,3,5-hexatriene as fluorescent probe, have shown that the lipophilic molecule fenofibrate changes phase behavior of DPPC liposomal membrane to a greater extent compared to the changes produced by amphiphilic simvastatin and hydrophilic niacin. This variation in effect can be attributed to the nature of the drug molecules and hence their location in different parts of the liposomal membrane. We have also calculated the changes in van’t Hoff enthalpy values in all these three cases and observed that these values decreased with increase in drug concentrations in the case of simvastatin but for fenofibrate and niacin the effect is completely the reverse. In order to get a better insight, the fraction of motionally restricted lipid molecules has been calculated.

Keywords:

• anti-hyperlipidemic drugs
• liposomal membrane
• fluorescence anisotropy
• van’t Hoff enthalpy change
• motionally restricted lipid molecules

Acknowledgements

This work was financially supported by Defense Research Development Organization and Council of Scientific and Industrial Research, Government of India. We thank Professor Guy Duportail, Directeur de Recherches Emérite, Laboratoire de Biophotonique et Pharmacologie, Université de Strasbourg, France for many stimulating and clarifying discussions. SB thanks Mr. Puskar Naskar, Physics Department, Jadavpur University for his skillful assistance.