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Vegetable oil-based microparticles were elaborated using environmentally friendly chemistry for pharmaceutical applications such as drug delivery systems. Castor oil (CO) was cross-linked by sol–gel chemistry to obtain a hybrid material offering original properties. CO functionalization was successfully achieved in the bulk with 3-isocyanatopropyltriethoxysilane (IPTES), then a simple and robust o/w emulsion process allowed both shaping functionalized oil into microparticles and favoring oil cross-linking. Several parameters were studied such as the stirring mode or the gelling agent for controlling microparticle characteristics. Spherical hybrid microparticles with a monodispersed size (around 300 μm) and a hybrid composition (13% w/w of mineral part) were characterized by size measurement, electronic microscopy, energy-dispersive X-ray spectroscopy, and thermal analysis. The effectiveness of the microparticles as potential drug delivery systems using ibuprofen as model molecule was demonstrated with a l...

International audience; The cationic ring-opening polymerization of 2-methyl-2-oxazoline (MOx) using iodine initiating system was reported. Uncolored polyoxazolines were produced in spite of the use of iodine initiator, well-known dye molecule. Low molecular weight asymmetric telechelic polyoxazolines carrying an acetylimine head group and an oxazolinium end group were synthesized, with a good control over the molecular weight. NMR and MALDI-Tof experiments allowed the full determination of the chemical structures of the produced poly(2-methyl-2-oxazoline)s, notably with the acetylimine head group, explained by spontaneous α-HI elimination. Finally, to our knowledge, we reported the first detailed mechanism of cationic ring-opening polymerization of 2-methyl-2-oxazoline in acetonitrile according to UV experiments. An ionic-type mechanism was involved with the dissociation of molecular iodine to active initiating species.

International audience; The polymerization of methyl methacrylate (MMA) initiated by 2,2'-azobis(isobutyronitrile) (AIBN) as radical initiator in the presence of iodine (I2) was studied at different temperatures (T = 70 C and 80 C). This process, called reverse iodine transfer polymerization (RITP), is based on the direct reaction of radicals with molecular iodine. RITP efficiently controls the molecular weight (determined by size exclusion chromatography, SEC) and the structure of the polymer chains (confirmed by 1H and 13C NMR spectroscopy). For instance, PMMA samples of Mn,SEC = 2300 g mol-1 and polydispersity index PDI = Mw/Mn = 1.5 (Mn,theoretical = 2300 g mol-1), Mn,SEC = 4600 g mol-1 and PDI = 1.6 (Mn,theoretical = 4700 g mol-1), Mn,SEC = 9600 g mol-1 and PDI = 1.6 (Mn,theoretical = 10 000 g mol-1), and Mn,SEC = 19 200 g mol-1 and PDI = 1.5 (Mn,theoretical = 18400 g mol-1) were successfully prepared by RITP. The polymerization was followed by on-line 1H NMR spectroscopy, and the conversion of iodine was followed by titration with a thiol (thioglycolic acid). It was shown by SEC, titration of iodine, gas chromatography, and NMR analyses that RITP was split into two different periods: a first "inhibition" period during which iodine is consumed to form very short -iodotelomers, and a second period where the polymerization follows the kinetics of a conventional free radical polymerization governed by degenerative chain transfer. The degenerative chain transfer constant was estimated to be Cex 2.6 at T = 80 C. Last, the iodine-end-capped structure of the polymers was demonstrated by different analytical techniques, and the iodine functionality of the PMMA chains was up to 95%.