Tretinoin-based formulations - influence of concentration and vehicles on skin penetration

Tretinoin is used in the management of acne and it is part of a gold standard treatment for photoaging. It has also been reported as an agent for superficial chemical peeling in highly concentrated formulations with few considerations about skin penetration. The aim of this study was to evaluate the influence of drug concentration and vehicles currently used on skin penetration of tretinoin. In vitro permeation tests were carried out using Franz diffusion cells fitted with porcine ear skin and 10% aqueous methanol in the receptor compartment. Formulations studied, cream or hydroalcoholic dispersion, containing 0.25%, 1% and 5% of tretinoin were placed in the donor compartment for six hours. Tretinoin concentration in skin layers was measured by high performance liquid chromatography. The largest amount of tretinoin from both vehicles was detected in stratum corneum with significant differences among the three concentrations. The hydroalcoholic dispersion was the best vehicle. Significant amounts of tretinoin were found even in deep layers of epidermis. The formulation with 0.25% tretinoin showed better results when considered the amount of tretinoin on skin in terms of percentage. Finally, skin penetration of tretinoin was influenced by vehicle and concentration of this drug used in formulation

Treball d'educació farmacèutica adreçat al pacient amb dolor crònic

Treballs d'Educació Farmacèutica als ciutadans. Unitat Docent d'Estades en Pràctiques Tutelades. Facultat de Farmàcia, Universitat de Barcelona. Curs: 2017-2018. Tutors: Montserrat Iracheta i Marian March Pujol.Pràcticament tothom sent dolor en algun moment de la seva vida; quan et fas un tall al dit, quan tens mal de cap... És la manera que té el nostre cos d’avisar que alguna cosa no va bé. Un cop el mal es cura, ja no es té més dolor. A diferència del dolor agut, entès com un signe d’alarma i reacció del cos davant d’una agressió, en el dolor crònic no sempre trobem una causa òbvia que l’expliqui en tota la seva magnitud. El dolor, en aquest cas, és un dels símptomes d’un terme més ampli que és el patiment, on aspectes psicològics i socials juguen un paper molt important. És un dolor que perdura setmanes, mesos o, fins i tot, anys

CDX2 regulation by the RNA-binding protein MEX3A: impact on intestinal differentiation and stemness

The homeobox transcription factor CDX2 plays a crucial role in intestinal cell fate specification, both during normal development and in tumorigenic processes involving intestinal reprogramming. The CDX2 regulatory network is intricate, but it has not yet been fully uncovered. Through genome-wide screening of a 3D culture system, the RNA-binding protein MEX3A was identified as putatively involved in CDX2 regulation; therefore, its biological relevance was addressed by setting up cell-based assays together with expression studies in murine intestine. We demonstrate here that MEX3A has a repressive function by controlling CDX2 levels in gastric and colorectal cellular models. This is dependent on the interaction with a specific binding determinant present in CDX2 mRNA 3'untranslated region. We have further determined that MEX3A impairs intestinal differentiation and cellular polarization, affects cell cycle progression and promotes increased expression of intestinal stem cell markers, namely LGR5, BMI1 and MSI1. Finally, we show that MEX3A is expressed in mouse intestine, supporting an in vivo context for interaction with CDX2 and modulation of stem cell properties. Therefore, we describe a novel CDX2 post-transcriptional regulatory mechanism, through the RNA-binding protein MEX3A, with a major impact in intestinal differentiation, polarity and stemness, likely contributing to intestinal homeostasis and carcinogenesis