Abstract
Parkinson’s disease is a movement disorder characterized by a progressive degeneration of dopaminergic neurons that has been object of study by the scientific community through the last decades. However, nowadays there is still no treatment to cure it, although there are drugs available, with limited efficacy, to relieve the symptoms or replenish the cells with dopamine to supply the lack of dopaminergic neurons. This work was structured in two parts. In the first one, binary aqueous solutions of l-dopa and cyclodextrins were studied. In the second part, ternary aqueous solutions of l-dopa were studied with each of the selected cyclodextrins. In all cases, thermodynamic properties (density, partial molar volume and thermodynamic transfer functions for temperatures between 294.15 ± 0.01 K and 312.15 ± 0.01 K) and transport properties (mutual diffusion coefficients, viscosity, transfer viscosity at 298.15 ± 0.01 K and 310.15 ± 0.01 K) were studied. Using theoretical models to adjust the experimental data obtained for the diffusion coefficients and for the apparent molar volumes, in the ternary aqueous solutions, it was possible to estimate the values to the l-dopa-cyclodextrin association constant. For the aqueous ternary solutes, the partial molar volume of transfer of levodopa in the presence of the cyclodextrins, the partial molar expansibility at infinite dilution and from this, the Hepler constant, were determined. Also, the values of Gibbs free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) were determined. From the obtained information, it was possible to characterize the molecular interactions, as well as to identify some structural characteristics of the controlled drug delivery systems under study and to estimate the influence of the cyclodextrin substituent groups, and, also, the temperature effect in the interaction levodopa-cyclodextrin. It is our intent to attain information about the mechanism of possible new systems for controlled drug delivery systems, throughout an alternative perspective, which could allow to increase its effectiveness in the Parkinson’s treatment.
Highlights
Parkinson disease (PD) is the most frequent movement disorder in the Western countries, afterAlzheimer’s disease, which turn it into one of the most studied diseases since its discovery [1].Its incidence in industrialized countries is close to 0.3% of the general population, affecting more men than women
For the case of non-electrolyte solutions, the apparent partial molar volume of the solute was determined by the Redlich equation [29], that assumes a linear dependence with the molar concentration, according to the following equation:
The mixtures in the results reported by our experimental method were prepared using mass fractions and converted to molar concentration by means of the relation wi = ci (Mi /ρ) where wi stands for the concentration in mass fraction, ci is molar concentration, Mi is the molar mass of the constituent i and ρ the density of the mixture
Summary
Parkinson disease (PD) is the most frequent movement disorder in the Western countries, after. Taking into account the main characteristics of the different cyclodextrins tested and, taking into consideration that the main drug used in the treatment of PD, L-dopa, has a limited solubility in water, which conditions its distribution by means of corporal fluids, as well as presents high adverse effects, it seems an advantageous therapeutic alternative its inclusion in a controlled drug release system with cyclodextrins. In this way, it is discussed in the present work the possibility to improve the applicability of. L -dopa, through the use of cyclodextrins to enable new formulations of the drug in the treatment against Parkinson’s disease
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
