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Projeto de investigação
Institute of Molecular Sciences
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Publicações
Designing type V deep eutectic solvents with antimalarial pharmaceutical ingredients
Publication . Teixeira, Gabriel; Brandão, Paula; Ferreira, Ana I.M.C. Lobo; Abranches, Dinis O.; Santos, L.uís M.N.B.F.; Ferreira, Olga; Coutinho, João A.P.
This work studies the formation of deep eutectic solvents formed by one active pharmaceutical ingredient
(quinine, pyrimethamine, or 2-phenylimidazopyridine) and a second component potentially acting as an
excipient (betaine, choline chloride, tetramethylammonium chloride, thymol, menthol, gallic acid, vanillin,
acetovanillone, 4-hydroxybenzaldehyde, syringaldehyde, propyl gallate, propylparaben, or butylated hydroxyanisole),
aiming to address challenges regarding drug solubility, bioavailability, and permeability. A preliminary
screening was carried out using the thermodynamic model COSMO-RS, narrowing down the search to
three promising excipients (thymol, propyl gallate, and butylated hydroxyanisole). Nine solid–liquid equilibrium
(SLE) phase diagrams were experimentally measured combining the three model drugs with the screened excipients,
and using a combination of a visual melting method and differential scanning calorimetry. Negative
deviations from thermodynamic ideality were observed in all nine systems. Furthermore, a total of four new
cocrystals were found, with powder and single crystal X-ray diffraction techniques being employed to verify their
unique diffraction patterns. In the thermodynamic modelling of the SLE diagrams, two COSMO-RS parametrizations
(TZVP and TZVPD-FINE) were also applied, though neither consistently delivered a better description
over the other.
Polyol-based deep eutectic solvents: betaine versus choline chloride
Publication . Teixeira, Gabriel; Abranches, Dinis O.; Yu, Gangqiang; Held, Christoph; Santos, Luís M. N. B. F.; Ferreira, Olga; Coutinho, João A. P.
This work investigates the potential of betaine as a substitute for choline chloride in the formation of polyol-based DES. The solid-liquid equilibrium (SLE) phase diagrams of binary mixtures of betaine with one polyol (ethylene glycol, 1,3-propanediol, glycerol, meso-erythritol, xylitol, or sorbitol) were studied across the entire composition range. Experimental measurements of the phase diagrams were limited by the thermal degradation of betaine and by the boiling points or high viscosities of some polyols. Overall, betaine exhibited negative deviations from ideality, while most polyols displayed near-ideal behaviour. COSMO-RS, a thermodynamic model, satisfactorily predicts these deviations from ideality and the observed phase behaviour. Mixtures of betaine and polyols yielded a narrower liquid-phase window for room-temperature applications than the corresponding choline chloride systems. The cross-association of betaine with polyols is more favourable than its self-association, and stronger interactions between the polyols and betaine than with choline chloride are expected, leading to more negative deviations; thus, the smaller melting temperature depression must result from a higher enthalpy of fusion of betaine than that of choline chloride.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
LA/P/0056/2020