Polycaprolactone and poly-β-cyclodextrin polymer blend: a Biopolymers composite film for drug release

Nowadays, biomedical films containing drug carriers are preferred over conventional ones, since the protection of the injury and the therapy is joined within a single device. In the current work, we prepared polycaprolactone (PCL) composite films with β-cyclodextrin (βCD) or its epichlorohydrin crosslinked polymer (βCDP) as ibuprofen (Ibu) drug carrier. The composite films were prepared at different PCL/additive ratios (2, 5, 10 and 20 wt%). ATR-FTIR spectroscopy and water contact angle (WCA) measurements indicated a scarce presence of the additives on the surface. Cross-section scanning electron micrographs showed the presence of aggregates corresponding to βCD and βCDP in the inner regions of the films. The incorporation of βCD and βCDP into the PCL films did not affect their thermal properties as was determined from differential scanning calorimetry (DSC). PCL-films with 10 wt% of the inclusion complexes Ibu@βCD and Ibu@βCDP were prepared and the release studies were performed. At pH?=?7.2, PCL-Ibu@βCDP composite film released 55% of Ibu within the first six hours; eight times the amount released by PCL-Ibu@βCD within the same time interval. A plausible mechanism for ibuprofen release is discussed based on the cross-section SEM micrographs of composite films.

     

Poly(amide)s obtained from 4-(4-((4-(4-aminophenoxy)phenyl)diphenylsilyl)phenoxy)benzenamine and dicarboxylic acids containing diphenylsilarylene units. Synthesis and characterization

A new symmetric aromatic diamine containing diphenylsilarylene and oxyphenyl units was synthesized and characterized. This diamine was used further for preparing poly(amide)s (O-PAs) when reacted with dicarboxylic acids containing diphenylsilarylene groups. Additionally, a poly(amide) without the oxyphenyl moieties in its structure was prepared by using the same polymerization method and was used as reference (PA-ref). All the PAs were characterized by spectroscopic, morphological, optical and thermal techniques. Likewise, their molecular weight was estimated by viscosity inherent measurements and MALDI-TOF mass spectrometry, and their solubility behavior was also studied. The results of these characterization showed that the incorporation of oxyphenyl moieties largely modifies the properties of the poly(amide)s, in accordance with the higher flexibility of the chain and their packaging possibilities.     

New oligomeric poly(ether-imide)s containing diphenylsilane and dibenzofuran moieties. Synthesis and characterization

A new aromatic diamine, 2,8-di(4-aminophenyl)dibenzofuran, was synthesized through the Suzuki C-C coupling reaction. This compound and an analoge diamine also based on a dibenzofuran moiety reacted with silylated-dianhydrides to yield three aromatic oligomeric poly(ether-imide)s (PEIs). The new diamine and the oligomers were characterized by elemental analysis, FT-IR, and NMR. Additionally, for the samples, solubility in an organic polar solvent was stablished and inherent viscosity values as an indirect measure of the molecular size were recovered. Some properties of PEIs were established and related to the specific structure of the repeating unit. In this sense, the rigidity/flexibility of the main chain fragments and the volume of groups bonded to silicon atom were responsible for the final properties of the polymers. All PEIs were obtained in high yield, but the inherent viscosities values of the soluble samples were low, indicating probably, low to moderated molecular sizes. The thermal decomposition temperatures measured by TGA varied from 490 to 562°C, and the Tg values ranged between 205 and 218°C. The solubility of all samples was tested in a series of common organic solvents at room temperature and at 40°C. The optical transparency in solution for the soluble samples was also determined.     

Silicon-containing oligomeric poly(imido-ester-amides) obtained from asymmetric dicarboxylic acids. Synthesis,characterization and thermal analysis

Poly(imido-ester-amides) (PIEAs) derived from three new asymmetric dicarboxylic acids containing an imide and ester groups and an aminoacidic moiety (glycine, L-alanine or L-valine) and a wholly aromatic silicon-containing diamine were synthesized according to the Yamazaki method. PIEAs were characterized by spectroscopic methods including ²⁹Si NMR and elemental analysis, and the results were in agreement with the proposed structures. The thermal properties, glass transition temperature (Tg) and thermal decomposition temperature (TDT), were determined and the results showed that both parameters decreased when the aliphatic side chain provides by the amino acids increased, due to the higher free volume between the chains, which minimizes the interactions between them. Two of the PIEAs showed transparency according to the UV-vis spectra, due to that the side chains act as chain spacers, in front of PIEA-a including glycine as aminoacidic moiety, without side aliphatic group, which did not show transparence.