Nanoparticles of beta-cyclodextrin esters obtained by self-assembling of biotransesterified beta-cyclodextrins.
The synthesis of decanoate beta-cyclodextrin esters (beta-CDd) and hexanoate beta-cyclodextrin esters (beta-CDh) was biocatalyzed by thermolysin from native beta-cyclodextrin (beta-CD) and vinyl hexanoate or vinyl decanoate used as acyl donors. The products were chemically characterized by infrared, NMR, and mass spectrometry. Both beta-CDd and beta-CDh esters were identified as a mixture of beta-CD preferentially substituted on the C2 position by the corresponding acyl chain. The degree of substitution varied from 2 to 7 for beta-CDd and from 4 to 8 for beta-CDh. The ability of beta-CD esters to self-organize into nanoparticles was tested using a nanoprecipitation technique in various solvents. The mean size diameter and polydispersity measured by quasi-elastic light scattering were dramatically affected by the nature of solvent (acetone, ethanol, or tetrahydrofuran) used in the nanoprecipitation technique. When directly observed using cryo-transmission electron microscopy, beta-CDh appeared as uniformly dense nanospheres, whereas beta-CDd exhibited a multilamellar onion-like organization. A structural model was rationalized for the beta-CDd nanoparticles.
Université Joseph Fourier, UFR de Pharmacie, ICMG DPM UMR CNRS 5063, 5 Avenue de Verdun, F-38243 Meylan Cedex, France. luc.choisnard@ujf-grenoble.fr
Luc
L
Choisnard
Annabelle
A
Gèze
Jean-Luc
JL
Putaux
Yung-Sing
YS
Wong
Denis
D
Wouessidjewe
D002208:Caproates / Q000737:chemistry; D002384:Catalysis; D011232:Chemical Precipitation; D020285:Cryoelectron Microscopy / Q000379:methods; D003651:Decanoates / Q000737:chemistry; D004952:Esters / Q000138:chemical synthesis* / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D012680:Sensitivity and Specificity; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013820:Thermolysin / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry*
D002208:Caproates; D003651:Decanoates; D004952:Esters; D012997:Solvents; D047392:beta-Cyclodextrins; D013820:Thermolysin