Comparison of techniques of drug redistribution registration from nanosized carriers in biological systems
Résumé
Nanosized liposomes are popular pharmaceutical carriers for drugs with poor water solubility, since they can be solubilized in the hydrophobic lipid bilayer. The use of liposomal formulations requires the development of non-invasive methods of drug release control in biological systems. In our study, a clinically approved photosensitizer, meta-tetra(hydroxyphenyl)chlorin (mTHPC) has been loaded into dimiristoylphosphatidylcholine-based liposomes. A high local concentration of the photosensitizer in liposomes produces the fluorescence features which may be used for analyzing the rate of pigment release from lipid carriers. We compare three different techniques to analyze the redistribution of mTHPC from liposomes to biological substrates: mTHPC anisotropy measurements, photoinduced mTHPC fluorescence quenching and excitation energy transfer from the fluorescent probe diphenylhexatrien (DPH) to mTHPC. Each method was shown to possess a characteristic range of sensitivity, with photoinduced quenching providing a better dynamic response.