Comparative evaluation of Pluronic® micelles encapsulation efficiency for a diverse range of hydrophobic drugs: Implications for drug delivery

The encapsulation of hydrophobic drugs within micellar carriers is a promising approach to improve their solubility, stability, and bioavailability. In this study, we conduct a thorough comparative analysis of the encapsulation capability of Pluronic (R) 103 micelle, known for its unique amphiphilic nature, which serves as nanocarriers for three hydrophobic drugs, viz. meloxicam, norfloxacin, and flurbiprofen. These drugs were chosen for their varying chemical structures and physicochemical properties. The interaction of these drugs with polymeric micelles was checked using Fourier transform infrared spectroscopy (FT-IR). Further, the study investigates the influence of salt on the micellar size and drug-loading efficiency of Pluronic (R) micelles for different drugs using a plethora of techniques such as dynamic light scattering (DLS), small angle neutron scattering (SANS), and high-performance liquid chromatography. Our results indicate that the presence of salt promotes micellization and significant differences in encapsulation efficiency among the drugs were noted, attributed to the interplay between the drug's hydrophobicity and the micellar core's compatibility. Further, the experimental findings revealed that Norfloxacin exhibited the highest encapsulation efficiency, while meloxicam showed the minimum. The outcomes of the study provide valuable insights into the drug-specific encapsulation behavior of Pluronic (R) micelles, offering guidance for the design of micellar drug delivery systems tailored to specific therapeutic agents.