Study of flavonoids/beta-cyclodextrins inclusion complexes by NMR, FT-IR, DSC, X-ray investigation.

Flavonoids are natural substances with a lot of biological activities, including the antioxidant one. Their use in pharmaceutical field is, however, limited by their aqueous insolubility. As the formation of the inclusion complexes can improve their solubility in water, the flavonoids hesperetin, hesperidin, naringenin and naringin have been complexed with beta-cyclodextrin (beta-CD) by the coprecipitation method and studied in solution and in solid state by NMR, FT-IR, differential scanning calorimetry and X-ray techniques. The effects of complexation on the chemical shifts of the internal and external protons of beta-CD in the presence of each flavonoid were observed.

Serum IgD levels in children with atopic asthma. A longitudinal study.

BACKGROUND: Serum IgD and IgE levels were measured in children with atopic asthma and in control Group in order to determine their relationship with clinical status. METHODS: Samples of venous blood (of 5 cc) were drawn from 25 asthmatic children (Group A) and 25 healthy children (Group B) at the moment of first diagnosis (T0), after 6 months (T180) and after 18 months (T540). To measure IgD, an ELISA assay based on the sandwich principle was used. RESULTS: At T0, IgD were significantly higher in Group A (182.7 5+/-88.18 IU/ml) in comparison with Group B (69.58+/-4.93 IU/ml, p<0.0001); IgD levels decreased in Group A at T540. CONCLUSIONS: In conclusion, a significant increase of IgD levels observed in children at first signs of asthma and the following normalization of these same levels after 18 months, may represent a non specific response or an attempt of the organism to block asthma, favouring therefore immunologic tolerance.

Study of beta-blockers/beta-cyclodextrins inclusion complex by NMR, DSC, X-ray and SEM investigation.

The formation of inclusion complexes between beta-cyclodextrin with the two beta-blockers, atenolol and celiprolol, have been studied in the aqueous environment and in the solid state by nuclear magnetic resonance (NMR) spectroscopy, X-ray, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) techniques. The magnitude of the chemical shifts of the interior and exterior beta-cyclodextrin protons in the presence of each beta-blocker indicated that these are included within the beta-cyclodextrin cavity. In aqueous solution they form 1:1 complexes. In the solid state the formation of the beta-cyclodextrin/atenolol (celiprolol) complexes is confirmed by X-ray, DSC and SEM, also employed to characterize pure substances and their physical mixtures.

Stability study of piroxicam and cinnoxicam in solid pharmaceuticals.

The pseudo-first order rate constant for the hydrolysis of cinnoxicam as a function of temperature was obtained by variable-temperature kinetic experiments. The method used is on a generalization of non-isothermal analysis, and takes advantage of the capabilities of modern data collection and processing systems. A spectrophotometric method under non isothermal conditions was carried out. The results obtained are identical to those obtained under the same conditions by using traditional constant-temperature kinetic runs. This provides the possibility of reducing the amount of time spent and chemicals usually used in collecting kinetic data in mechanistic studies in solution by an order of magnitude.

Isolation and characterization of Guiera senegalensis J.F.Gmel. active principles.

A combination of thin-layer chromatography, high-performance liquid chromatography, UV spectroscopy and NMR spectrometry techniques for analysis of flavonoid content of Guiera senegalensis J.F.Gmel. (Combretaceae) leaves is described. Four components, catechin, myricitrin, rutin and quercetin were evidenced and determined by HPLC.