Yolima Baena

TEMPERATURE-DEPENDENCE OF THE SOLUBILITY OF SOME ACETANILIDE DERIVATIVES IN SEVERAL ORGANIC AND AQUEOUS SOLVENTS

The thermodynamic functions free energy, enthalpy, and entropy of solution, were evaluated from the solubility data of acetanilide, acetaminophen, and phenacetin, determined at several temperatures in water, octanol, isopropyl myristate, and chloroform. These three organic solvents mutually saturated with water, and finally, in cyclohexane. In the aqueous media, the solubility was determined at pH 7.4 and ionic strength 0.15 mol L−1. The excess free energy and the activity coefficients of the solutes were also determined. The solubility for acetanilide and phenacetin was higher in organic media such as octanol and chloroform than is those obtained in the aqueous media and cyclohexane, while for acetaminophen the solubility was higher in octanol than those obtained in the other solvents.

Interaction between DNA and Drugs Having Protonable Basic Groups: Characterization through Affinity Constants, Drug Release Kinetics, and Conformational Changes

This paper reports the in vitro characterization of the interaction between the phosphate groups of DNA and the protonated species of drugs with basic groups through the determination of the affinity constants, the reversibility of the interaction, and the effect on the secondary structure of the macromolecule. Affinity constants of the counterionic condensation DNA–drug were in the order of 106. The negative electrokinetic potential of DNA decreased with the increase of the proportion of loading drugs. The drugs were slowly released from the DNA–drug complexes and had release kinetics consistent with the high degree of counterionic condensation. The circular dichroism profile of DNA was not modified by complexation with atenolol, lidocaine, or timolol, but was significantly altered by the more lipophilic drugs benzydamine and propranolol, revealing modifications in the secondary structure of the DNA. The in vitro characterization of such interactions provides a physicochemical basis that would contribute to identify the effects of this kind of drugs in cellular cultures, as well as side effects observed under their clinical use. Moreover, this methodology could also be projected to the fields of intracellular DNA transfection and the use of DNA as a carrier of active drugs.

Peruvioses A to F, sucrose esters from the exudate of Physalis peruviana fruit as α-amylase inhibitors

The fruit of Physalis peruviana is widely used in traditional Colombian medicine as an antidiabetic treatment. The aim of the study reported here was to identify the compounds responsible for the hypoglycemic activity using the α-amylase inhibition test. Bioguided fractionation of a dichloromethane extract of the sticky exudate that covers the fruit allowed the isolation and identification of three new sucrose esters, named as peruvioses C-E (1-3), along with the known peruvioses A (6), B (5) and F (4), the structures of which were elucidated by extensive NMR and MS experiments. These compounds proved to be responsible for the hypoglycemic activity observed in the extract. Peruviose D (2) showed the highest activity, with an inhibitory activity value of 84.8%. This is the first study to establish the potential of sucrose esters as α-amylase inhibitors and to explain the hypoglycemic effect that has traditionally been attributed to gooseberry fruit.

Thermodynamic quantities of solvation and dilution for some acetanilide derivatives in octanol and water mutually saturateds

Based on published thermodynamic quantities for solution, partitioning and sublimation of acetanilide (ACN), acetaminophen (ACP) and Phenacetin (PNC), the thermodynamic quantities for drugs solvation in octanol-saturated water (W(ROH)) and water-saturated octanol (ROH(W)) as well as the drugs dilution in ROH(W) were calculated. The Gibbs energies of solvation were favourable in all cases. The respective enthalpies and entropies were negative indicating an enthalpy-driving for the sol- vation process in all cases. On the other hand, the Gibbs energies of dilution were favourable for ACP and PNC but unfavourable for ACN, whereas the respective enthalpies and entropies were negative for ACP and PNC but positive for ACN indicating enthalpy-driving for the dilution process in the case of the former drugs and entropy-driving for the latter. From the obtained values for the transfer process- es, an interpretation based on solute-solvent interactions was developed.

Evaluación de la intercambiabilidad in vitro de diferentes marcas de tabletas de diclofenaco sódico del mercado colombiano

Introducción. El diclofenaco sódico se clasifica como un antiinflamatorio no esteroide. Dado que es de venta libre, el paciente no tiene ningún seguimiento por parte de los equipos de salud, y como sus fuentes son múltiples, es necesario establecer la equivalencia entre ellas en estudios in vitro, que son los más prácticos y plantean un menor compromiso ético.Objetivos. Determinar la intercambiabilidad de diferentes marcas comerciales de diclofenaco sódico comparadas con el producto innovador mediante un estudio in vitro de tabletas comerciales de 50 mg, según los lineamientos del Sistema de Clasificación Biofarmacéutica (SCB).Materiales y métodos. Se desarrollaron pruebas físicas y químicas siguiendo las indicaciones de la edición 39 de la United States Pharmacopeia (USP). Para la cuantificación, se validó una metodología analítica según lo establecido en la mencionada farmacopea y la guía Q2 del International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). Los perfiles de disolución y sus análisis se rigieron por lo establecido por la Organización Mundial de la Salud y las normas nacionales.Resultados. Todos los productos aprobaron las pruebas físicas. En cuanto a la disolución, la etapa ácida también fue superada por todas las marcas, pero una marca falló en la etapa alcalina. El análisis de similitud reveló que solo un producto fue equivalente al innovador y tres fueron supradisponibles, aunque dichas marcas también podrían considerarse equivalentes al producto innovador.Conclusiones. De las ocho marcas evaluadas, tres no cumplieron totalmente con la prueba de valoración del principio activo y del porcentaje de disolución; solo una marca fue intercambiable con el producto innovador y tres fueron supradisponibles comparadas con este, por lo cual no constituyen un riesgo para el paciente.