The PEG2,40K conjugate of IFN-alpha2b has increased in vitroand in vivo stability as compared to the native cytokine.

SbstractOxaliplatin was inserted into polymeric matrices aiming to study the interaction of this drug with these polymers and its capability to diffuse to the environment. Tested polymers were: (1) polyethylene glycol (PEG), (2) poly(lactic-co-glycolic acid) (PLGA), and (3) a copolymer of them (PLGA-PEG). The latter two were synthesized by us using polycondensation in bulk. Oxaliplatin was included in the matrices by the melt mixing process followed by casting. Fourier tran sform infrared spectroscopy (FTIR), proton nuclear magnetic resonance ( 1 H-NMR) and X-ray diffraction (DRX) studies of the polymers were performed proving the obtaining of the desired materials. In addition, the interaction between drug and matrices and the release profile of the oxaliplatin from these matrices were analyzed. Among them, PEG did not control the oxaliplatin release. In turn, PLGA and PLGA-PEG present drug release profiles quite similar. Oxaliplatin was completely released from PLGA and PLGA-PEG in 5 hours, by a relaxation mechanism. There was no evidence of oxaliplatin interaction with the different polymers. In addition, as the PEG improves the biocompatibility and biomasking, obtained results prove the obtaining of a drug release system, which allowed the total use of the drug improving the cancer treatment and even the welfare of the patients.

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Researching for new biomaterials intended for drug delivery systems has considerably intensified in recent years. There is an increasing interest in PBS (poly[butylene succinate]) and its copolymers as biomaterials due to the possibility of synthesis of the PBS from a renewable source. Among these copolymers, PBS‐PEG (poly[butylene succinate‐co‐polyethylene glycol]) is studied for materials that have shape memory and are biodegradable. However, to date, no research into the use of PBS‐PEG to prepare microspheres for drugs release has been reported. Herein, PBS‐PEGs with three PEG with different chain′s length were synthesized by polycondensation reaction and characterized by means of SEC, FTIR, DSC, TGA, and DRX. Naproxen loaded microspheres were prepared by an oil‐in‐water (o/w) single emulsion technique. The drug release was followed by UV‐Vis. The presence of PEG had a marked effect on the in vitro release profiles. The mathematical models employed show that the fundamental mechanism of release is diffusion when PEG is present in the polymer matrix of the particle.