Browsing by Author "Chierotti, Michele R."

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    Enhanced Oral Bioavailability of Vinpocetine Through Mechanochemical Salt Formation: Physico-Chemical Characterization and In Vivo Studies
    (Springer, 2011-03-19) Hasa, Dritan; Voinovich, Dario; Perissutti, Beatrice; Grassi, Mario; Bonifacio, Alois; Sergo, Valter; Cepek, Cinzia; Chierotti, Michele R.; Gobetto, Roberto; Dall’Acqua, Stefano; Invernizzi, Sergio
    Purpose Enhancing oral bioavailability of vinpocetine by forming its amorphous citrate salt through a solvent-free mechanochemical process, in presence of micronised crospovidone and citric acid. Methods The impact of formulation and process variables (amount of polymer and citric acid, and milling time) on vinpocetine solubilization kinetics from the coground was studied through an experimental design. The best performing samples were characterized by employing a multidisciplinary approach, involving Differential scanning calorimetry, X-ray diffraction, Raman imaging/spectroscopy, X-ray photoelectron spectroscopy, solid-state NMR spectroscopy, porosimetry and in vivo studies on rats to ascertain the salt formation, their solidstate characteristics and oral bioavailability in comparison to vinpocetine citrate salt (Oxopocetine®). Results The analyses attested that the mechanochemical process is a viable way to produce in absence of solvents vinpocetine citrate salt in an amorphous state. Conclusion From the in vivo studies on rats the obtained salt was four times more bioavailable than its physical mixture and bioequivalent to the commercial salt produced by conventional synthetic process implying the use of solvent.
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    Mechanochemical activation of vincamine mediated by linear polymers: Assessment of some ‘‘critical’’ steps
    (Elsevier, 2013-03-21) Hasa, Dritan; Perissutti, Beatrice; Grassi, Mario; Chierotti, Michele R.; Gobetto, Roberto; Ferrario, Valerio; Lenaz, Davide; Voinovich, Dario
    The aim of the research was to investigate three ‘‘critical steps’’ that deserve particular attention during the mechanochemical activation of vincamine. The first step consisted in the selection of the best polymeric carrier/most affine stabiliser between linear PVP and NaCMC by using the GRID and the GRID based AutoDock software packages which permit to calculate their surface features and interactions. Moreover, the calculation of the partial and total solubility parameters supported the results obtained by GRID and AutoDock software. Then, after the selection of linear PVP-K30 as the suitable carrier, the influence of process and formulation variables on the amorphisation degree and solubility enhancement was studied, to select the most suitable process conditions and formulation parameters. Subsequently, the best performing samples were widely characterised using XRPD, TEM and SSNMR (including the proton relaxation (1H T1 NMR) time) techniques. These studies highlighted that all the coground samples were nanocrystalline solid dispersions indicating a dramatic difference between the amorphisation capacities of linear PVP-K30 and cross-linked PVP, used in previous analogous experiences. In particular, 13C, 15N and 1H T1 NMR data point to a description of the system as a dispersion of nanocrystals in the polymer. In these dispersions vincamine is in a disordered crystalline state due to extensive interactions and contacts with PVP-K30 but the main hydrogen bonding motif characterising its packing remains. Again, differently from cross-linked PVP, dissolution studies revealed that linear PVP-K30 was able to promote a complete in vitro solubilisation of vincamine in some coground samples. What is more important, by using a linear polymer, drugto- polymer and milling time variables appeared less influent on the solid state and in vitro properties of the composites. Finally, stability studies conducted for a period of 1 year highlighted the high physical stability of the selected samples.
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    Mechanochemically induced disordered structures of vincamine: The different mediation of two cross-linked polymers
    (Elsevier, 2012-06-18) Hasa, Dritan; Perissutti, Beatrice; Chierotti, Michele R.; Gobetto, Roberto; Grabnar, Iztok; Bonifacio, Alois; Dall’Acqua, Stefano; Invernizzi, Sergio; Voinovich, Dario
    The aims of this research were to prepare highly bioavailable binary cogrounds (vincamine–AcDiSol® or PVP-Cl) by means of a mechanochemical process and to study the mediation of each polymer in the induction of physical transformations of the drug. From a set of fifteen cogrounds for each crosslinked polymer, two samples were selected in each group on the basis of the AUC of in vitro dissolution profiles with the help of a statistical comparison. The chosen samples were analysed by means of TEM, XRPD, Raman-spectroscopy/imaging, SSNMR, also including the study of 1H spin–lattice relaxation times. The research encompassed in vivo oral absorption studies in rats, pharmacokinetic analysis and physical stability studies during 1 year. An intimate drug–polymer mixing was found in the coground samples with domain average dimensions smaller than 100A˚ ; this reflected in a remarkable enhancement of the in vitro and in vivo bioavailability. Different disordered states were detected in the coground samples as a function of cogrinding time and the type and amount of polymer used. Though both crosslinked polymers produced a remarkable enhancement of the oral bioavailability, coground systems based on AcDiSol® are preferable in terms of pharmacokinetic performance and physical stability.
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    A new soluble and bioactive polymorph of praziquantel
    (Elsevier, 2018-01-31) Zanolla, D.; Perissutti, Beatrice; Passerini, N.; Chierotti, Michele R.; Hasa, Dritan; Voinovich, Dario; Gigli, L.; Demitri, N.; Geremia, S.; Keiser, J.; Vioglio, P.C.
    Praziquantel is the only available drug to treat Schistosomiasis. However, its utilization is limited by many drawbacks, including the high therapeutic dose needed, resulting in large tablets and capsules difficult to be swallowed, especially from pediatric patients. In this study, an alternative option to overcome these disadvantages is proposed: to switch to a novel crystalline polymorph of racemic compound praziquantel. The preparation of the crystalline polymorph was realized via a neat grinding process in a vibrational mill. The new phase (Form B) was chemically identical to the starting material (as proved by HPLC, 1H NMR, and polarimetry), but showed different physical properties (as evaluated by SEM, differential scanning calorimetry, thermogravimetry, ATR-FTIR spectroscopy, X-ray powder diffraction, and solid-state NMR). Furthermore, the crystal structure of the new phase was solved from the powder synchrotron X-ray diffraction pattern, resulting in a monoclinic C2/c cell and validated by DFT-D calculation. Moreover the simulated solid-state NMR 13C chemical shifts were in excellent agreement with the experimental data. The conversion of original praziquantel into Form B showed to affect positively the water solubility and the intrinsic dissolution rate of praziquantel. Both the in vitro and in vivo activity against Schistosoma mansoni were maintained. Our findings suggest that the new phase, that proved to be physically stable for at least one year, is a promising product for designing a new praziquantel formulation.
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    Rationale of using Vinca minor Linne dry extract phytocomplex as a vincamine’s oral bioavailability enhancer
    (Elsevier, 2012-12-11) Hasa, Dritan; Perissutti, Beatrice; Dall’Acqua, Stefano; Chierotti, Michele R.; Gobetto, Roberto; Grabnar, Iztok; Cepek, Cinzia; Voinovich, Dario
    Vincamine is a poorly soluble potent neuroprotector and cerebral vasodilator, used for the treatment for CNS disorders. In some cases, the bioavailability of pure compounds is strongly influenced by the co-administration of other constituents, and in some cases, the so called ‘phytocomplex’ may act as enhancer of absorption of selected phytochemicals. In this paper, the oral bioavailability of vincamine when administered as a standardised Vinca minor L. leaf dry extract rather than pure indole alkaloid is demonstrated to be higher. The chosen alkaloid-enriched and standardised dry extract was widely characterised by means of HPLC–MS, PXRD, DSC, XPS, 13C and 15N solid-state NMR (SSNMR) using pure vincamine as a matter of comparison. Then, the in vitro dissolution performances of the two products and their in vivo bioavailability in rats were evaluated. The sevenfold improvement in oral bioavailability of the dry extract with respect to the pure vincamine was ascribed to interactions between the indole alkaloid and the corollary of ingredients of the dry extract, giving rise to the protonation of the alkaloid vincamine, thus enhancing its dissolution in physiological fluids. Present data demonstrate that alkaloid vincamine administered as a whole plant extract has a higher bioavailability compared to the pure chemical compound.