Generalization of the Carothers equation for linear step growth polymers.

In the synthesis of linear step-growth polymers molecular weight control is accomplished through the addition of a controlled amount of monomer carrying the functional group B in excess (B-B or H-B types). The Carothers equation is used to calculate average chain lengths. This paper extends the analysis of chain lengths to include the effect of monofunctional monomers carrying the limiting group A (H-A), allowing the systematic analysis of complex systems containing both bifunctional and monofunctional species of any type (A-A, B-B, H-B and H-A).

Physicochemical Characterization and In Vitro Activity of Poly(ε-Caprolactone)/Mycophenolic Acid Amorphous Solid Dispersions.

The obtention of amorphous solid dispersions (ASDs) of mycophenolic acid (MPA) in poly(ε-caprolactone) (PCL) is reported in this paper. An improvement in the bioavailability of the drug is possible thanks to the favorable specific interactions occurring in this system. Differential scanning calorimetry (DSC) was used to investigate the miscibility of PCL/MPA blends, measuring glass transition temperature (T) and analyzing melting point depression to obtain a negative interaction parameter, which indicates the development of favorable inter-association interactions.

Amorphous solid dispersions in poly(ε-caprolactone)/xanthohumol bioactive blends: physicochemical and mechanical characterization.

This paper reports the obtention of amorphous solid dispersions (ASDs) of xanthohumol (XH) in PCL containing up to 50 wt% of the bioactive compound in the amorphous form thanks to the advantageous specific interactions established in this system. The miscibility of the PCL/XH blends was investigated using DSC. Melting point depression analysis yielded a negative interaction parameter indicating the occurrence of favorable inter-association interactions.

Novel Hydrogels of Chitosan and Poly(vinyl alcohol) Reinforced with Inorganic Particles of Bioactive Glass.

Chitosan (CS) and poly(vinyl alcohol) (PVA) hydrogels, a polymeric system that shows a broad potential in biomedical applications, were developed. Despite the advantages they present, their mechanical properties are insufficient to support the loads that appear on the body. Thus, it was proposed to reinforce these gels with inorganic glass particles (BG) in order to improve mechanical properties and bioactivity and to see how this reinforcement affects levofloxacin drug release kinetics.