| Autor: |
Bagheri M; Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Faculty of Science , Utrecht University , 3508 TB Utrecht , The Netherlands., Bresseleers J; ChemConnection BV , 5349 AB Oss , The Netherlands.; Department of Bio-Organic Chemistry , Eindhoven University of Technology , 5600 MB Eindhoven , The Netherlands., Varela-Moreira A; Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Faculty of Science , Utrecht University , 3508 TB Utrecht , The Netherlands.; Department of Clinical Chemistry and Haematology , University Medical Centre Utrecht , 3584 CX Utrecht , The Netherlands., Sandre O; Laboratoire de Chimie de Polymères Organiques , Université de Bordeaux, UMR 5629 CNRS , 33607 Pessac , France., Meeuwissen SA; ChemConnection BV , 5349 AB Oss , The Netherlands., Schiffelers RM; Department of Clinical Chemistry and Haematology , University Medical Centre Utrecht , 3584 CX Utrecht , The Netherlands., Metselaar JM; Department of Nanomedicine and Theranostics , Institute for Experimental Molecular Imaging RWTH University Clinic , 52074 Aachen , Germany., van Nostrum CF; Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Faculty of Science , Utrecht University , 3508 TB Utrecht , The Netherlands., van Hest JCM; Department of Bio-Organic Chemistry , Eindhoven University of Technology , 5600 MB Eindhoven , The Netherlands., Hennink WE; Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Faculty of Science , Utrecht University , 3508 TB Utrecht , The Netherlands. |
| Abstrakt: |
Micelles composed of block copolymers of poly(ethylene glycol)- b-poly( N-2-benzoyloxypropyl methacrylamide) (mPEG- b-p(HPMA-Bz)) have shown great promise as drug-delivery carriers due to their excellent stability and high loading capacity. In the present study, parameters influencing micelle size were investigated to tailor sizes in the range of 25-100 nm. Micelles were prepared by a nanoprecipitation method, and their size was modulated by the block copolymer properties such as molecular weight, their hydrophilic-to-hydrophobic ratio, homopolymer content, as well as formulation and processing parameters. It was shown that the micelles have a core-shell structure using a combination of dynamic light scattering and transmission electron microscopy analysis. By varying the degree of polymerization of the hydrophobic block ( N B ) between 68 and 10, at a fixed hydrophilic block mPEG 5k ( N A = 114), it was shown that the hydrophobic core of the micelle was collapsed following the power law of ( N B × N agg ) 1/3 . Further, the calculated brush height was similar for all the micelles examined (10 nm), indicating that crew-cut micelles were made. Both addition of homopolymer and preparation of micelles at lower concentrations or lower rates of addition of the organic solvent to the aqueous phase increased the size of micelles due to partitioning of the hydrophobic homopolymer chains to the core of the micelles and lower nucleation rates, respectively. Furthermore, it was shown that by using different solvents, the size of the micelles substantially changed. The use of acetone, acetonitrile, ethanol, tetrahydrofuran, and dioxane resulted in micelles in the size range of 45-60 nm after removal of the organic solvents. The use of dimethylformamide and dimethylsulfoxide led to markedly larger sizes of 75 and 180 nm, respectively. In conclusion, the results show that by modulating polymer properties and processing conditions, micelles with tailorable sizes can be obtained. |
