Francisco Torrens - Academia.edu (original) (raw)

Papers by Francisco Torrens

Current Topics in Medicinal Chemistry, Jun 16, 2015

The problem in this work is the computational characterization of cyclodextrins, crown ethers and... more The problem in this work is the computational characterization of cyclodextrins, crown ethers and hyaluronan (HA) as hosts of inclusion complexes for nanosized drug delivery vehicles in pharmaceutical formulations. The difficulty is addressed through a computational study of some thermodynamic, geometric and topological properties of the hosts. The calculated properties of oligosaccharides of D-glucopyranoses allow these to act as co-solvents of polyanions in water. In crown ethers, the central channel is computed. Mucoadhesive polymer HA in formulations releases drugs in mucosas. Geometric, topological and fractal analyses are carried out with code TOPO. Reference calculations are performed with code GEPOL. From HA to HA·3Ca and hydrate, the hydrophilic solvent-accessible surface varies with the count of H-bonds. The fractal dimension rises. The dimension of external atoms rises resulting 1.725 for HA. It rises going to HA·3Ca and hydrate. Nonburied minus molecular dimension rises and decays. Hydrate globularity is lower than O(water), Ca(2+) and O(HA). Ca(2+) rugosity is smaller than for hydrate, O(HA) and O(water). Ca(2+) and O(water) accessibilities are greater than hydrate. Conclusions are drawn on: (1) the relative stability of linear/cyclic and shorter/larger polymers; (2) the atomic analysis of properties allows determining the atoms with maximum reactivity.

BENTHAM SCIENCE PUBLISHERS eBooks, Mar 27, 2012

Molecules, Dec 31, 2004

Valence topological charge-transfer (CT) indices are applied to the calculation of dipole moments... more Valence topological charge-transfer (CT) indices are applied to the calculation of dipole moments. The algebraic and vector semisum CT indices are defined. The combination of CT indices allows the estimation of the dipole moments. The model is generalized for molecules with heteroatoms. The ability of the indices for the description of the molecular charge distribution is established by comparing them with the dipole moments of homologous series of percutaneous enhancers (phenyl alcohols and 4-alkylanilines). Linear and quadratic correlation models are obtained. CT indices improve the multivariable quadratic regression equations for the dipole moment. The variance decreases 97% (4-alkylanilines). No superposition of the corresponding G k-J k and G k V-J k V pairs is observed in the fits, which diminishes the risk of co-linearity. The inclusion of the heteroatom in the π-electron system is beneficial for the description of the dipole moment, owing to either the role of the additional p orbitals provided by the heteroatom or the role of steric factors in the π-electron conjugation. Inclusion of a conjugated double bond in the alkyl chain lends to more rigid structures with dipole moment variations <1%.

Bioorganic & Medicinal Chemistry, Apr 1, 2005

The TOpological MOlecular COMputer Design (TOMOCOMD-CARDD) approach has been introduced for the c... more The TOpological MOlecular COMputer Design (TOMOCOMD-CARDD) approach has been introduced for the classification and design of antimicrobial agents using computer-aided molecular design. For this propose, atom, atom-type, and total quadratic indices have been generalized to codify chemical structure information. In this sense, stochastic quadratic indices have been introduced for the description of the molecular structure. These stochastic fingerprints are based on a simple model for the intramolecular movement of all valence-bond electrons. In this work, a complete data set containing 1006 antimicrobial agents is collected and presented. Two structure-based antibacterial activity classification models have been generated. The models (including nonstochastic and stochastic indices) classify correctly more than 90% of 1525 compounds in training sets. These models permit the correct classification of 92.28% and 89.31% of 505 compounds in an external test sets. The TOMOCOMD-CARDD approach, also, satisfactorily compares with respect to nine of the most useful models for antimicrobial selection reported to date. Finally, a virtual screening of 87 new compounds reported in the antiinfective field with antibacterial activities is developed showing the ability of the TOMOCOMD-CARDD models to identify new leads as antibacterial.

Proceedings of MOL2NET 2018, International Conference on Multidisciplinary Sciences, 4th edition, Dec 13, 2018