Inclusion of cinnamaldehyde in modified γ-cyclodextrins

This work deals with the formation of inclusion complexes between cinnamaldehyde and two synthetic alkylcarbonates of γ-cyclodextrin, namely ethylcarbonate-γ-CD and octylcarbonate-γ-CD. Complexation was monitored by phase-solubility studies, by FT-IR spectroscopy and by DSC and TG analysis. The diffusion of cinnamaldehyde through a cellulose membrane was investigated in the absence and in the presence of each of the two γ-CD alkylcarbonates. Studies on photostability and stability over time were carried out on different cosmetic formulations containing pure cinnamaldehyde or an equivalent amount of cinnamaldehyde complexed with the two alkylcarbonates. Phase-solubility diagrams, DSC, FTIR and TGA analysis suggested the formation of inclusion complexes. The diffusion of cinnamaldehyde through the cellulose membrane decreased in the presence of the two alkylcarbonates confirming the interaction of this molecule with the inclusion agents. Moreover the stability of cinnamaldehyde to light and heat resulted increased by complexing this fragrance material with the two alkylcarbonates.     

Which degrees of freedom play a role in multinucleon transfer processes?

A presentation of some recent significant results obtained in the field of multinucleon transfer reactions at Coulomb barrier energies is given. The comparison of the experimental observables with the predictions of theoretical models treating quasi-elastic and deep-inelastic processes on the same ground reveals interesting features of the reaction mechanisms not clearly identified in the past.     

Disentangling the reaction mechanisms of weakly bound nuclei

Complete and incomplete fusion cross sections for the ⁹Be + ¹⁴⁴Sm reaction have been measured at near-barrier energies, using the delayed X-ray detection technique. At above-barrier energies these show a suppression of complete fusion for this weakly bound projectile on an intermediate mass target. The suppression factor, attributed to ⁹Be break-up, was deduced from a comparison of complete fusion yields with coupled-channels calculations, and appears consistent with measured incomplete fusion product yields. At ∼10%, it is considerably smaller than the value of ∼30% previously found for a ²⁰⁸Pb target. Simultaneous measurements of elastic and inelastic scattering permit a clearer picture of the reaction mechanisms.     

Asymmetric Synthesis in the Presence of Cyclodextrins

Oxidative couplings of 2-naphthol, 6-bromo-2-naphthol and2-naphthylamine were achieved at room temperature in the presence of H₂O₂, horseradish peroxidase and a suitable cyclodextrin.2-Thionaphthol behaved differently, yielding the corresponding disulfide. Yields of binaphthyl derivatives were generally excellent, and a fairly good enantiomeric excess was observed. Under similar reaction conditions methyl 2-(6-methoxy-2-naphthyl) propanoate, when treated with esterase in the presence of cyclodextrin, yielded naproxen (a well-known anti-inflammatory drug) with a good enantiomeric excess. No reaction product was detected in the absence of cyclodextrin. Cyclodextrins do not act as simple transfer agents.     

On the determination of crystallinity and cellulose content in plant fibres

A comparative study of cellulose crystallinity based on the sample crystallinity and the cellulose content in plant fibres was performed for samples of different origin. Strong acid hydrolysis was found superior to agricultural fibre analysis and comprehensive plant fibre analysis for a consistent determination of the cellulose content. Crystallinity determinations were based on X-ray powder diffraction methods using side-loaded samples in reflection (Bragg-Brentano) mode. Rietveld refinements based on the recently published crystal structure of cellulose Iβ followed by integration of the crystalline and amorphous (background) parts were performed. This was shown to be straightforward to use and in many ways advantageous to traditional crystallinity determinations using the Segal or the Ruland–Vonk methods. The determined cellulose crystallinities were 90–100 g/100 g cellulose in plant-based fibres and 60–70 g/100 g cellulose in wood based fibres. These findings are significant in relation to strong fibre composites and bio-ethanol production.     

Deformable liposomes containing alkylcarbonates of γ-cyclodextrins for dermal applications

Liposomes made with hydrogenated soya lecithin (HPC) mixed with dodecylcarbonate γ-cyclodextrin (C12CD) at 20:1, 10:1 and 5:1 w/w ratios were prepared by the solvent evaporation method. C12CD had emulsifying properties and the possibility of producing deformable liposomes, as topical delivery system of progesterone (PG), was evaluated. Liposome size, deformability and drug entrapment were determined and the interaction between C12CD and HPC was investigated using differential scanning calorimetry (DSC). The size and the amount of PG loaded in the liposomes depended on the lipid:C12CD ratio: the smallest liposomes were obtained using 20:1 ratio and the maximum drug entrapment at 5:1 ratio. DSC analysis suggested that C12CD interacted with liposomes disrupting and fluidizing the lipid bilayer. PG transepidermal permeation through intact pig skin and PG skin uptake from deformable liposomes were assessed and compared to the values obtained from aqueous suspension and conventional liposomes. The PG permeations were negligible for all systems, while skin uptake increased for liposomes containing C12CD. This was attributed to the deformability and to the increase in the drug entrapment efficiency of these liposomes. The use of C12CD in liposome formulations can improve PG topical therapy.     

An Improved Measurement of Isotopic Ratios by High Resolution Mass Spectrometry

The study of protein kinetics requires an accurate measurement of isotopic ratios of peptides. Although Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometers yield accurate mass measurements of analytes, the isotopologue ratios are consistently lower than predicted. Recently, we demonstrated that the magnitude of the spectral error in the FT-ICR mass spectrometer is proportional to the scan duration of ions. Here, we present a novel isotopic ratio extrapolation (IRE) method for obtaining accurate isotopic ratio measurements. Accuracy is achieved by performing scans with different duration and extrapolation of the data to the initial moment of the ion rotation; IRE minimizes the absolute isotopic ratio error to ≤1 %. We demonstrate the application of IRE in protein turnover studies using ²H₂O-metabolic labeling. Overall, this technique allows accurate measurements of the isotopic ratios of proteolytic peptides, a critical step for enabling routine studies of proteome dynamics.      

Thermosensitive Gels for the Topical Administration of Diltiazem

In the present work, thermosensitive systems were prepared, characterized, and proposed for diltiazem administration in the topical treatment of anal fissures. Methylcellulose and PluronicF127 were used as gelling polymers. Some low-toxicity molecules, such as sodium glycocholate, citric acid, and lactic acid, were added to gel formulations as counterions to enhance diltiazem lipophilicity. The systems were characterized by sol-gel transition temperature, viscosity, and rheological studies. The resulting data allowed us to determine which systems presented sol-gel transition. A change from Newtonian to plastic behavior at sol-gel transition temperature was observed. An increase in diltiazem pig skin permeability and two-fold skin accumulation was observed in the presence of citric acid.