1,721,021 research outputs found
More than “just a drop”: the enigmatic role of liquid additives in mechanochemistry
No full textWe debate the role of liquid additives in liquid-assisted mechanochemistry, highlighting how miniscule amounts of liquid profoundly and mostly inexplicably affect the mechanism and outcomes of mechanochemical reactions. A critical analysis of well-known mechanochemistry studies, along with those reporting emerging concepts (such as the competitive liquid effect and dual-function liquids) underpins the complexity and mystery surrounding mechanochemical processes and suggest where the most series gaps in our understanding of mechanochemistry lie
Cocrystal Formation through Mechanochemistry: from Neat and Liquid-Assisted Grinding to Polymer-Assisted Grinding
No full textAbstract: Mechanochemistry is an effective method for the preparation of multicomponent crystal systems. In the present work, we propose an alternative to the established liquidassisted grinding (LAG) approach. Polymer-assisted grinding (POLAG) is demonstrated to provide a new class of catalysts for improving reaction rate and increasing product diversity during mechanochemical cocrystallization reactions. We demonstrate that POLAG provides advantages comparable to the conventional liquid-assisted process, whilst eliminating the risk of unwanted solvate formation as well as enabling control of resulting particle size. It represents a new approach for the development of functional materials through mechanochemistry, and possibly opens new routes toward the understanding of the mechanisms and pathways of mechanochemical cocrystal formation
An innovative oxytetracycline self-emulsifying formulation for fish diets: preparation,characterisation and oral bioavailability in Rainbow Trout (Oncorhyncus mykiss)and in EuropeanSea Bass (Dicentrarchus Labrax)
No full textThe aim of this study was to develop a self-emulsifying system (SES) with practical applications in fish farming. In particular, the lipid vehicle
was developed in order to deliver oxytetracycline hydrocloride to rainbow trout (RT) and European sea bass (ESB) so as to improve the drug’ s
oral bioavailability. The developed formulation was assessed in comparison to an aqueous solution working with two fish species (one fresh-water
and one salt-water), after oral administration with a gastric probe. Results indicated an enhancement of bioavailability of 5.86 and 5.41 times
over the aqueous solution, in RT and ESB, respectively. SES was then used to prepare medicated feed containing the formulation. The pharmacokinetic
of this feed was evaluated after oral administration and compared to that of commercial OTC medicated feed. The bioavailability of OTC
delivered in SES was 3.2 times higher in RT and 2.7 times higher in ESB, than OTC supplied by commercial medicated feed. This bioavailability
enhancement was confirmed when RT were fed by classical administration in fish tanks of single and repeated administration of OTC delivered
in SES and commercial medicated feed, attesting to better absorption of the SES formulation
2D DYNAMICAL SIMULATION OF A VIBRATIONAL MILL
No full text2D DYNAMICAL SIMULATION OF A VIBRATIONAL MIL
EFFECT OF COMPOSITION ON THE RELEASE FROM MELT EXTRUDED LAMINAR SYSTEMS BY APPLICATION OF MIXTURE EXPERIMENTAL DESIGN
No full textEFFECT OF COMPOSITION ON THE RELEASE FROM MELT EXTRUDED LAMINAR SYSTEMS BY APPLICATION OF MIXTURE
EXPERIMENTAL DESIG
Modification of urinary metabolic profile after oral administration of curcuma extract in rats
No full textDrug Salt Formation via Mechanochemistry: The Case Study of Vincamine
No full textIn the present research a salt of vincamine, a poorly bioavailable indole alkaloid derived from the leaves of Vinca minor L., was synthesized in the solid state by means of a mechanochemical process employing citric acid as a reagent. The mechanochemical process was adopted as a solvent-free alternative to classical citrate synthetic route that involves the use of solvents. Since the mechanochemical salification is little studied to date and presents the disadvantage of offering a low
yield, in this work, the influence of three process and formulation variables on the percentage of vincamine citrate was studied. In particular, the time of mechanical treatment (in planetary mill Fritsch P5) and the amount of citric acid were varied in order to evaluate their effect on the yield of the process, and the introduction of a solid solvent, a common pharmaceutical excipient (sodium carboxymethylcellulose, NaCMC), was considered. Due to the complexity of the resulting samples’ matrix, an appropriate experimental design was employed to project the experimental trials and the influence of the three variables on the experimental response was estimated with the help of a statistical analysis. The experimental response, that
is, the yield of the process corresponding to the percentage of vincamine in the protonated form, was unconventionally calculated by means of X-ray photoelectron spectroscopy analysis (XPS). Out of 16 samples, the one with the highest yield was the coground sample containing vincamine and citric acid in a 1:2 molar ratio, treated for 60 min in the presence of NaCMC. Under the above conditions the salification reaction was completed highlighting the importance of a proper selection of process and formulation variables of the mechanochemical salification, and emphasizing the crucial role of the solid solvent in facilitating the salification. The second step of the research encompassed the characterization of the citrate salt obtained by solid excipient assisted mechanochemical salification (SEAMS) in comparison with the vincamine citrate obtained by classical synthetic route. The samples were characterized by, besides XPS, high resolution transmission electron microscopy (HRTEM), X-ray powder diffraction (XRPD), in vitro solubilization kinetics and in vivo oral pilot study in rats. Finally, in order to monitor over time possible disproportionation phenomena, stability studies have been performed by repeating XPS analysis after 8 months. As expected, the the SEAMS-vincamine salt consisted of particles both crystalline and amorphous. The solubilization kinetics was superior to the corresponding salt probably thanks to the favorable presence of the hydrophilic excipient although the two salts were bioequivalent in rats after oral administration. Furthermore, no evidence of disporportionation phenomena in the SEAMSvincamine salt was found after storage. In conclusion, in the case of forming salts of poorly soluble drugs, the SEAMS process may be an interesting alternative to both classical synthetic routes, eliminating the need for solvent removal, and simple neat mechanochemical salification, overcoming the problem of limited process yiel
Development and pharmacokinetic evaluation of erythromycin lipidic formulations for oral administratiom in rainbow trout (O. mykiss)
No full textThe aim of this work was to enhance the bioavailability of erythromycin base when administered orally in rainbow trout (Oncorhynchus mykiss). Since erythromycin is normally given in the form of medicated feed, in this study three new types of feed formulation were developed. A self-emulsifying system and two types of double microemulsions (O/W/O) were prepared, characterized and adsorbed on a commercial extruded diet for fish. The three medicated feed were then administered orally by means of a gastric probe to rainbow trout and their relative bioavailability was estimated in comparison with that obtained after oral administration of feed with erythromycin powder. For each medicated feed, 80 fish were tested. Finally, plasma profiles of erythromycin after single administration of medicated feeds were used to predict profiles obtainable by administering once-daily medicated feeds for 7 consecutive days
Monitoring polymer-assisted mechanochemical cocrystallisation through in situ X-ray powder diffraction
No full textTime-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the investigation of polymer-assisted grinding reactions using in situ X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of the polymer additive used
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