Micelles have aroused interest due to their ability to assist in the transport of poorly soluble drugs. In this study the mixture of copolymers F127/E45S8 in different proportions (F/ES 30/70, 50/50 and 70/30) was performed to improve the bioavailability of griseofulvin and quercetin. The results of cytotoxicity (MTT assay) revealed that the copolymers F127 and E45S8 had considerable biocompatibility and did not affect the metabolism of human neutrophils. The binary systems were also evaluated by critical micellar concentration (CMC) and thermoresponsive behavior. The CMC values were intermediate to those of the isolated copolymers. The systems maintained the thermoresponsive properties present in F127 making the systems interesting for subcutaneous administration. The systems presented small size, an average range in size from 17 to 38 nm, and the samples prepared with higher hydrophobic proportion presented more uniform sizes. Results suggest stability and the increasing of the nanosystems circulation time. The F/ES 30/70 system has polydispersity smaller than 0.1 and showed an increase of 129 times for quercetin solubility. Thus, it is possible to consider F127/E45S8 micelles as potential nanosystems for poorly soluble drug delivery.

Improving the development of modified release matrix systems strictly depends on selecting an appropriate agent capable of controlling the drug's release. In this study, Adenanthera pavonina galactomannan was investigated as a potential basis for developing a controlled release of rutin. This galactomannan was extracted, purified and characterized by GPC, NMR and FT-IR spectroscopy. The mannose/galactose ratio (M/G) of 1.46 was calculated by the relative area from signals of the anomeric region of 1H-NMR spectrum. The main chain of this galactomannan consists of β(1®4)-D-mannose and α(1®6)-D-galactose linked units (1H-decoupled 13C NMR, 13C DEPT 135º NMR and HSQC spectra). The sustained-release tablets containing rutin and galactomannan were compared with the extensively investigated hydrophilic matrix HPMC. Drug release analysis revealed similar release mechanism for both matrices. A new formulation for controlled drug delivery from water-swellable matrix systems is proposed.

Binary mixtures of block copolymers E114CL20 and E97P69E97 (F127(®)) were prepared in order to tailor a drug delivery system with synergistic effect, concerning dilution stability and high drug solubility. Both reduction of the critical micelle concentrations (CMC) values and enhance hydrophobic drug solubility in F127/E114CL20 mixtures (30-50 wt.%) were observed by addition of the diblock E114CL20, also reaching the best enhancement of drug solubility for mangiferin and carbamazepine.