Salicylic acid permeation: a comparative study with different vehicles and membranes

Considering the skin's function, different dermal pharmaceutical forms can be developed according to the type of therapeutic activity, active principle and excipients involved in the formulation, such as [quot ]transdermal preparations[quot ]. In the present study, the permeation parameters of the non-steroidal anti-inflammatory drug, salicylic acid (SA) through synthetic membrane, polyvinyliden difluoride, and a biological membrane, egg shell membrane, with different vehicles, propylene glycol, isopropyl alcohol and carbopol gel, were determined. The reported physicochemical parameters of SA from CG were significantly higher than those obtained using PG and IP. This is attributed to the lipophilic nature of the vehicle that facilitates the release and penetration of the active principle, thus acting sinergicall y. The permeation profiles of SA allow us to state that permeation kinetics is of first order, so that the flux values obtained are in direct proportion to the specific rates of drug release.

Bacteriostatic action of synthetic polyhydroxylated chalcones against Escherichia coli

In previous work the bacteriostatic action of trihydroxylated chalcones against Staphylococcus aureus ATCC 25 923 was investigated. In this work the action of 2',4',2-(OH)3-chalcone, 2',4',3-(OH)3-chalcone and 2',4',4-(OH)3-chalcone against Escherichia coli ATCC 25 922 was evaluated. Growth kinetic curves of E. coli were made in nutritive broth added with increasing drug concentrations. The specific growth rates of the microorganisms were calculated by a kinetic turbidimetric method, which was previously probed and the minimal inhibitory concentrations (MIC's) were evaluated by a mechanism of action proposed. The MICs of 2',4',3-(OH)3-chalcone and 2',4',2-(OH)3-chalcone were 46 microg/ml and 122 microg/ml, respectively. The 2',4',4-(OH)3-chalcone was inactive. The MIC value of 2',4',3-(OH)3-chalcone (46 microg/ml), more active than 2',3-(OH)2-chalcone (72.2 microg/ml) may be due to the introduction of an electron donating group (-OH) at position 4' in the aromatic A-ring, which activates the region that includes the 2'-hydroxyl neighbor group and the alpha,beta-unsaturated carbonyl group.

Cinética de la acción bacteriostática de chalconas naturales y de síntesis sobre una cepa de Staphylococcus aureus / Kinetics of the bacteriostatic action of synthetic and natural chalcones on a Staphylococcus aureus strain

Se estudió la acción bacteriostática ejercida por chalconas naturales (2',4'-dihidroxichalcona y 2'-hidroxi-4'-metoxichalcona) y de síntesis (chalcona, 2'-hidroxicalcona, 2'4-dihidroxichalcona y 2'-hidroxi-4-metoxichalcona) sobre Staphylococcus aureus (cepa ATCC 25 923). Se determinó la influencia de la concentración de la natureza y posición de los sustituyentes de las drogas empleadas sobre la tasa de crecimiento específica del germen. Los ensayos cualitativos se hicieron en placas de agar nutritivo y mostraron la acción inhibitoria de chalcona y sus derivados dihidroxilados. Los resultados obtenidos distiguen el potente efecto bacteriostático de 2',4'-dihidroxichalcona y 2',4'-dihidrochalcona que en bajas concentraciones provocaron inhibición total en el crecimiento del microorganismo, de las otras chalconas estudiadas que solamente disminuyeron la tasa de crecimiento específica del germe hasta un valor límite. Se observa que la presencia de un grupo oxihidrilo en el anillo A o B de la 2'-hidroxichalcona potencia su actividad bacteriostática siendo este efecto más pronunciado en la posición 4'(anillo A) respecto de la posición 4 (anillo B). La introducción de un grupo metoxilo en la estructura de la 2'-hidroxichalcona produce un decrecimiento de su potencia inhibitoria