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The purpose of the present study was to evaluate the enhancement of tolbutamide (TBM) oral bioavailability and hypoglycaemic activity through complexation with b-cyclodextrin (b-CD) and hydroxypropyl-b-cyclodextrin (HP-b-CD). TBM and its freeze-dried inclusion complexes were administered to rabbits (New zealand breed; n =6), in a dose of 20 mg/kg. TMB plasma levels were measured by HPLC and glucose levels were analysed according to Trinder (Trinder, P., 1969. Determination of glucose in blood using glucose oxidase with an alternative oxygen acceptor. Ann. Clin. Biochem. 6, 24-28). The pure drug attained a maximum of plasma concentration (C max ) of 18.5893.27 mg/ml at 8.5 h (T max ), whereas with inclusion complexes, C max increased about two times and appeared at ca. 4 h. AUC 0-24 of complexes was about 1.6 times as much as that of the pure drug. Thus, the extent of oral absorption of TBM from inclusion complexes was significantly greater and faster when compared with drug alone. In addition, without cyclodextrins the maximum hypoglycaemic effect (CVG max ) of TBM (34.1%) was observed at 5.6 h (Tg max ). CVG max of TBM/b-CD and TBM/HP-b-CD inclusion complexes were 34.1% (at 6.5 h) and 37.7% (at 5.1 h), respectively. AAC 0-24 of inclusion complexes was 1.4 times larger than that of pure drug. Hence, the oral administration of complexed TBM not only improved the drug absorption, but also the TBM hypoglycaemic activity.

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Lignocellulosic biomass fractionation is typically performed using methods that are somehow harsh to the environment, such as in the case of kraft pulping. In recent years, the development of new sustainable and environmentally friendly alternatives has grown significantly. Among the developed systems, bio-based solvents emerge as promising alternatives for biomass processing. Therefore, in the present work, the bio-based and renewable chemicals, levulinic acid (LA) and formic acid (FA), were combined to fractionate lignocellulosic waste (i.e., maritime pine sawdust) and isolate lignin. Different parameters, such as LA:FA ratio, temperature, and extraction time, were optimized to boost the yield and purity of extracted lignin. The LA:FA ratio was found to be crucial regarding the superior lignin extraction from the waste biomass. Moreover, the increase in temperature and extraction time enhances the amount of extracted residue but compromises the lignin purity and reduces its molecular weight. The electron microscopy images revealed that biomass samples suffer significant structural and morphological changes, which further suggests the suitability of the newly developed bio-fractionation process. The same was concluded by the FTIR analysis, in which no remaining lignin was detected in the cellulose-rich fraction. Overall, the novel combination of bio-sourced FA and LA has shown to be a very promising system for lignin extraction with high purity from biomass waste, thus contributing to extend the opportunities of lignin manipulation and valorization into novel added-value biomaterials.

The feasibility of using complexes with cyclodextrins (CDs) in nicardipine (NC) controlled delivery has been examined, with a view to extending the pharmaceutical applications spectrum of these carriers. For a fast release fraction, a hydrophilic beta-cyclodextrin derivative (hydroxypropyl-beta-cyclodextrin) was employed to form a water-soluble complex. For the sustained-releasing portion, triacetyl-beta-cyclodextrin (TAbetaCD) was used to provide complexes with appropriate hydrophobicity. An optimal formulation was designed by the combination of each fraction in different mixing ratios. The release behaviour of the complexes, as well as of their mixtures, was examined in simulated gastric (pH 1.2) and intestinal (pH 6.8) fluids. The formulations released the drug rapidly at the initial stage, followed by a slow release. The drug release rate was markedly retarded in the increasing order of the amount of NC/TAbetaCD complex. When NC was administered to rabbits, its absorption was very rapid with a short elimination half-life, while a prolonged maintenance of the plasma levels was obtained for the two selected formulations. The drug bioavailability was considerably improved especially after the administration of the mixture of hydrophilic and hydrophobic complexes, when compared with the NC/TAbetaCD complex. The results suggested that the critical combination of hydrophilic and hydrophobic CDs complexes, in appropriate ratios, could be a promising drug delivery system with a prolonged therapeutic effect coupled with a more balanced bioavailability.

Infrared spectra of inclusion compounds of triacetyl‒β‒cyclodextrin with nicardipine hydrochloride were compared and analysed with those corresponding to their physical mixture and the pure compounds, respectively. Different O–H stretching vibrations, assigned to water molecules, were located in the Fourier Transform Infrared (FT IR) spectra of triacetyl‒β‒cyclodextrin, and its inclusion complex with nicardipine obtained by spray‒drying (SD) method. Water molecules involved in various hydrogen bonds environments change their status during complexation process. Evidences are observed of the formation of the complex especially in the spectral regions of the amino and carbonyl stretching vibrations.

A novel drug delivery concept based on the encapsulation of liposomes in biodegradable dextran-based microspheres was designed. The system released the liposomes in intact form in a controlled way after a prolonged period of time.