Effect of Hydrophobicity of PEO–PPO–PEO Block Copolymers on Micellization and Solubilization of a Model Drug Nimesulide

Abstract

The present work explored the molecular implications governing the solubilization of a model drug nimesulide (NIM) in micelles of ethylene oxide‐propylene oxide (EO–PO) triblock copolymers. The aggregation behavior and solubilization studies on four copolymers each with the same mol mass of central PPO block equal to 2,250 and varying % PEO was examined by means of UV–VIS. Moreover, high‐sensitivity differential scanning calorimetry, and Fourier transform infrared spectrometry measurements were used to evaluate the critical micellization temperature. The solubilization at different temperatures (30, 37, 45 °C), pH (2 to 10) and in the presence of added sodium chloride (0–2 M) was monitored and the partition coefficient (P) and the free energy of solubilization (ΔGso) were calculated. The site of solubilization of NIM in micelles was also probed. The NIM solubility decreased with increases in the PEO molecular weight; the drug resides in the micelle core.

Calorimetric and Scattering Studies on Micellization of Pluronics in Aqueous Solutions: Effect of the Size of Hydrophilic PEO End Blocks, Temperature, and Added Salt

“…The CPs of 5% solution of L81, P84, and P85 were 293, 346, and 357 K, respectively and are in agreement with literature values. [11,33] For F87 and F88, CP exceeded 373 K due to the large PEO block and therefore, CP measurements were made at different NaCl concentrations ( Figure 1). A linear decrease in CP with an addition of NaCl has been observed for polyoxyethylenebased nonionic surfactant due to the salting out effect.…”

Supramolecular Nanostructures Based on Cyclodextrin and Poly(ethylene oxide): Syntheses, Structural Characterizations and Applications for Drug Delivery

“…CD derivatives can also influence the characters, both the inclusions and the poly(pseudo)rotaxanes. The complexation behavior off our β-CD derivatives, including DIMEB (heptakis(2,6-di- O -methyl)-β-CD), TRIMEB (heptakis(2,3,6-tri- O -methyl)-β-CD), HEBCD(hydroxyethyl-β-CD), and HPBCD(hydroxypropyl-β-CD), with micelles of Pluronic F127(PEO 100 - b -PPO 65 - b -PEO 100 ), were investigated and the disassembly behavior between the CDs and the micelles was reported [49]. The interactions involving the CD derivatives and inclusions could lead to the disassembly, which resulted from the methyl groups in position 6 of the glucopyranose rings of DIMEB and TRIMEB with the inclusions, such as PPO.…”