RESUMEN
The aim of this study was to investigate dermal delivery of the new active pharmaceutical ingredient (API) TOP-N53 into diabetic foot ulcer using an in vitro wound model consisting of pig ear dermis and elucidate the impact of drug formulation and wound dressing taking into consideration clinical relevance in the home care setting and possible bacterial infection. Different formulation approaches for the poorly water-soluble API including colloidal solubilization, drug micro-suspension and cosolvent addition were investigated; moreover, the effect of (micro-)viscosity of hydrogels used as primary wound dressing on delivery was assessed. Addition of Transcutol® P as cosolvent to water improved solubility and was significantly superior to all other approaches providing a sustained three-day delivery that reached therapeutic drug levels in the tissue. Solubilization in micelles or liposomes, on the contrary, did not boost delivery while micro-suspensions exhibited sedimentation on the tissue surface. Microbial contamination was responsible for considerable metabolism of the drug leading to tissue penetration of metabolites which may be relevant for therapeutic effect. Use of hydrogels under semi-occlusive conditions significantly reduced drug delivery in a viscosity-dependent fashion. Micro-rheologic analysis of the gels using diffusive wave spectroscopy confirmed the restricted diffusion of drug particles in the gel lattice which correlated with the obtained tissue delivery results. Hence, the advantages of hydrogel dressings from the applicatory characteristic point of view must be weighed against their adverse effect on drug delivery. The employed in vitro wound model was useful for the assessment of drug delivery and the development of a drug therapy concept for chronic diabetic foot ulcer. Mechanistic insights about formulation and dressing performance may be applied to drug delivery in other skin conditions such as digital ulcer.
Asunto(s)
Pie Diabético , Hidrogeles , Cicatrización de Heridas , Porcinos , Animales , Cicatrización de Heridas/efectos de los fármacos , Pie Diabético/tratamiento farmacológico , Hidrogeles/química , Sistemas de Liberación de Medicamentos/métodos , Administración Cutánea , Viscosidad , Solubilidad , Vendajes , Química Farmacéutica/métodos , Piel/metabolismo , Piel/efectos de los fármacos , Enfermedad Crónica , Composición de Medicamentos/métodosRESUMEN
Besides deposition, pulmonary bioavailability is determined by dissolution of particles in the scarce epithelial fluid and by cellular API uptake. In the present work, we have developed an experimental in vitro model, which is combining the state-of-the-art next generation impactor (NGI), used for aerodynamic performance assessment of inhalation products, with a culture of human alveolar A549 epithelial cells to study the fate of inhaled drugs following lung deposition. The goal was to investigate five previously developed nano-milled and spray-dried budesonide formulations and to examine the suitability of the in vitro test model. The NGI dissolution cups of stages 3, 4, and 5 were transformed to accommodate cell culture inserts while assuring minimal interference with the air flow. A549 cells were cultivated at the air-liquid interface on Corning® Matrigel® -coated inserts. After deposition of aerodynamically classified powders on the cell cultures, budesonide amount was determined on the cell surface, in the interior of the cell monolayer, and in the basal solution for four to eight hours. Significant differences in the total deposited drug amount and the amount remaining on the cell surface at the end of the experiment were found between different formulations and NGI stages. Roughly 50% of budesonide was taken up by the cells and converted to a large extent to its metabolic conjugate with oleic acid for all formulations and stages. Prolonged time required for complete drug dissolution and cell uptake in case of large deposited powder amounts suggested initial drug saturation of the surfactant layer of the cell surface. Discrimination between formulations with respect to time scale of dissolution and cell uptake was possible with the present test model providing useful insights into the biopharmaceutical performance of developed formulations that may be relevant for predicting local bioavailability. The absolute quantitative result of cell uptake and permeation into the systemic compartment is unreliable, though, because of partly compromised cell membrane integrity due to particle impaction and professed leakiness of A549 monolayer tight junctions, respectively.
Asunto(s)
Broncodilatadores/metabolismo , Budesonida/metabolismo , Colágeno/metabolismo , Composición de Medicamentos/métodos , Laminina/metabolismo , Proteoglicanos/metabolismo , Mucosa Respiratoria/metabolismo , Células A549 , Broncodilatadores/administración & dosificación , Budesonida/administración & dosificación , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Colágeno/administración & dosificación , Combinación de Medicamentos , Humanos , Laminina/administración & dosificación , Proteoglicanos/administración & dosificación , Mucosa Respiratoria/efectos de los fármacos , SolubilidadRESUMEN
Acid-catalyzed transannular cyclization of the germacrene-type sesquiterpene lactone nobilin 1 was investigated with the aim of obtaining new anti-trypanosomal cadinane derivatives. The reaction was regiospecific in all tested reaction conditions. Compounds were fully characterized by spectroscopic and computational methods, and the anti-trypanosomal activity was evaluated and compared to nobilin (IC50 3.19±1.69µM). The tricyclic derivative 11 showed most potent in vitro activity against Trypanosoma brucei rhodesiense bloodstream forms (IC50 0.46±0.01µM). Acid-catalyzed transannular cyclization of natural cyclodecadienes is an efficient strategy to generate new natural product derivatives with anti-protozoal activity.
Asunto(s)
Bibencilos/síntesis química , Lactonas/síntesis química , Sesquiterpenos de Germacrano/síntesis química , Sesquiterpenos/síntesis química , Tripanocidas/síntesis química , Trypanosoma brucei rhodesiense/efectos de los fármacos , Bibencilos/farmacología , Chamaemelum , Ciclización , Humanos , Lactonas/farmacología , Sesquiterpenos Policíclicos , Sesquiterpenos/farmacología , Sesquiterpenos de Germacrano/farmacología , Tripanocidas/farmacologíaRESUMEN
The objective of this work was first to investigate the chemical degradation of the sesquiterpene lactone nobilin and determine its solubility under conditions of concurrent degradation for partially amorphous starting material; second, to determine the effect of biorelevant media used in the in vitro measurement of intestinal absorption on degradation and solubility of nobilin. Purely aqueous medium (aq-TMCaco ), fasted and fed state simulated intestinal fluid (FaSSIF-TMCaco and FeSSIF-TMCaco ), and two liposomal formulations (LiposomesFaSSIF and LiposomesFeSSIF ) with the same lipid concentration as FaSSIF-TMCaco and FeSSIF-TMCaco were used. Degradation products were identified by nuclear magnetic resonance and X-ray crystallography and the order of reaction kinetics was determined. Solubility was deduced with a mathematical model encompassing dissolution, degradation, and reprecipitation kinetics that took into account particle size distribution of the solid material. Degradation mechanism of nobilin involved water-catalyzed opening of the lactone ring and transannular cyclization resulting in five degradation products. Degradation followed first-order kinetics in aq-TMCaco and FaSSIF-TMCaco , and higher-order kinetics in FeSSIF-TMCaco and the two liposomal formulations, whereas degradation in the latter media was diminished. Solubility of nobilin increased in the order: aq-TMCaco < FaSSIF-TMCaco , < LiposomesFaSSIF < FeSSIF-TMCaco < LiposomesFeSSIF . Improvement of stability and solubility was consistent with the incorporation of the nobilin molecule into colloidal lipid particles. The developed kinetic model is proposed to be a useful tool for deducing solubility under dynamic conditions.
Asunto(s)
Modelos Químicos , Sesquiterpenos de Germacrano/química , Cromatografía Líquida de Alta Presión , Cristalografía por Rayos X , Cinética , Tamaño de la Partícula , SolubilidadRESUMEN
Lychnophora salicifolia, commonly known as "arnicão", is used as an anti-inflammatory agent and as a flavoring agent in the Brazilian traditional spirit "cachaça". In this work, the permeation process of vicenin-2 (1) and lychnopholic acid (2) (major secondary metabolites from the hydroalcoholic extract) was investigated using Caco-2 cells. For this investigation, a new HPLC-DAD method was developed and validated for the quantification step. It was observed that 2 crosses the Caco-2 cell monolayer by passive diffusion. On the other hand, 1 was not transported, suggesting no absorption and no efflux of this compound in Caco-2 cells.