Authors:B. Pose-Vilarnovo, C. Rodríguez-Tenreiro Sánchez, N. Diéguez Moure, J. Vila-Jato, and J. Torres-Labandeira
The effect of a hydrophilic polymer, hydroxypropylmethyl cellulose K4M, on the complexation of diclofenac sodium with b- and
hydroxypropyl-b-cyclodextrins has been studied. Multicomponent systems were prepared with the drug, both cyclodextrin and
the polymer. Phase solubility diagrams revealed the positive effect of the polymer on the complexation of the drug but this
effect was found after autoclaving the solutions. Solid inclusion complexes were prepared by freeze-drying and characterized
by thermal analysis (DSC) and X-ray diffractometry. In solid state, binary inclusion complexes enhance the dissolution behaviour
of diclofenac but, from the b-cyclodextrin multicomponent complex, the polymer controls the release of the drug. In the case
of hydroxy- propyl-b-cyclodextrin multicomponent system, the solubility of the drugs increases significantly compared with
the binary complex.
Authors:B. Pose-Vilarnovo, X2 Rodríguez-Tenreiro Sánchez, M. Pérez-Marcos, and J. Torres-Labandeira
The effect of cyclodextrin complexation of sulphamethizole (SM) was studied. Two systems were prepared with two cyclodextrin
derivatives, β-cyclodextrin (BCD) and hydroxypropyl-β-cyclodextrin (HPBCD): binary complexes and multicomponent systems (cyclodextrins
and a hydroxylpropylmethyl cellulose K4M). Inclusion complexes were prepared by freeze-drying and characterized by thermal
analysis (DSC) and X-ray diffractometry. The presence of the polymer in the solution increases the effect of cyclodextrins
– specially BCD – on the solubility of SM. In solid state, binary inclusion complexes enhance the dissolution behaviour of
SM but, from the multi-component complexes, the polymer controls the release of the drug.
Authors:Carmen Rodríguez-Tenreiro, Carmen Alvarez-Lorenzo, Ángel Concheiro, and J. Torres-Labandeira
The interactions between Carbopol and β-cyclodextrin (BCD) or hydroxypropyl-β-cyclodextrin (HPBCD) were studied by differential
scanning calorimetry (DSC) and FTIR spectroscopy. Aqueous solutions of both components were desiccated by freeze-drying or
heating in an oven (films) at various temperatures. The use of different drying procedures allowed their influence on the
interactions to be studied. The evolution of the Carbopol glass-transition was also evaluated by DSC using first heating runs
up to different temperatures. Disappearance of the Carbopol glass-transition was observed in the freeze-dried systems prepared
with either of the cyclodextrins and in the films that contained HPBCD. The changes in the FTIR band of Carbopol at 1700 cm-1 confirmed the existence of interactions with both cyclodextrins, especially with HPBCD. This information may be useful for
optimising the solubilizing capacity and controlled release performance of aqueous Carbopol-cyclodextrin systems.
Authors:José Lamartine Soares-Sobrinho, Monica Felts de La Roca Soares, Pedro José Rolim-Neto, and Juan J. Torres-Labandeira
Although not being the ideal drug due to its low solubility and high toxicity, the benznidazole is the drug currently chosen for Chagas disease treatment. The deep knowledge about the characteristics of the drug in addition to the knowledge of more effective vectorization techniques of drugs in pharmaceutical forms allows a faster and cheaper development of a new therapeutic alternative in comparison to the introduction of a new molecule in the treatment. The aim of this study is the characterization of inclusion complexes Benznidazole and cyclodextrins in solid state. The interactions between Benznidazole (BNZ) and β-cyclodextrins (β-CD) modified: randomly methylated β-CD (RMβCD) and sulfobutylether β-CD (SBβCD) were studied by differential scanning calorimetry (DSC), fourier transform-infrared spectroscopy, RAMAN, and scanning electron microscopy. The preparation of solid-state binary systems by different techniques, namely, kneading, evaporated, and freeze-drying. The results suggest the formation of inclusion complexes of the drug with both CDs types in solid state by the techniques which were used, based on physicochemical data of interaction compared to the drug or the CDs/drug physical mixture. Thus, the preparation technique played an important role in the BNZ and modified CDs.