Alternative Methods for Pulmonary-Administered Drugs Metabolism: A Breath of Change.

Prediction of pulmonary metabolites following inhalation of a locally acting pulmonary drug is essential to the successful development of novel inhaled medicines. The lungs present metabolic enzymes, therefore they influence drug disposal and toxicity. The present review provides an overview of alternative methods to evaluate the pulmonary metabolism for the safety and efficacy of pulmonary delivery systems. In vitro approaches for investigating pulmonary drug metabolism were described, including subcellular fractions, cell culture models and lung slices as the main available in vitro methods. In addition, in silico studies are promising alternatives that use specific software to predict pulmonary drug metabolism, determine whether a molecule will react with a metabolic enzyme, the site of metabolism (SoM) and the result of this interaction. They can be used in an integrated approach to delineate the major cytochrome P450 (CYP) isoforms to rationalize the use of in vivo methods. A case study about a combination of experimental and computational approaches was done using fluticasone propionate as an example. The results of three tested software, RSWebPredictor, SMARTCyp and XenoSite, demonstrated greater probability of the fluticasone propionate being metabolized by CYPs 3A4 at the S1 atom of 5-S-fluoromethyl carbothioate group. As the in vitro studies were not able to directly detect pulmonary metabolites, those alternatives in silico methods may reduce animal testing efforts, following the principle of 3Rs (Replacement, Reduction and Refinement), and contribute to the evaluation of pharmacological efficacy and safety profiles of new drugs in development.

Effects of a novel roflumilast and formoterol fumarate dry powder inhaler formulation in experimental allergic asthma.

In this study we aimed to develop a roflumilast (R) and formoterol fumarate (F) dry powder inhaler formulation (DPI) incorporating HPßCD by spray drying and evaluated if it attenuates the inflammatory process and improves lung function in a murine model of ovalbumin induced allergic asthma. The DPI was characterized by powder X-ray diffraction, thermal analysis, scanning electron microscopy, particle size, density, specific surface area and dynamic vapor sorption analyses. In vitro deposition studies were performed using a NGI, while transepithelial permeability and in vivo effects on lung mechanics and inflammation in a model of allergic asthma were also assessed. The R:F formulation was amorphous with high glass transition temperatures, comprised of wrinkled particles, had low bulk and tapped densities, high surface area, suitable particle size for pulmonary delivery and exhibited no recrystallization even at high relative humidities. MMAD were statistically similar of 4.22 ± 0.19 and 4.32 ± 0.13 µm for F and R, respectively. Fine particle fractions (<5 µm) were of more than 50% of the emitted dose. The R:F formulation led to reduced eosinophil infiltration and airway collagen fiber content, yielding decreased airway hyperresponsiveness. In the current asthma model, the R:F formulation combination decreased inflammation and remodeling, thus improving lung mechanics.

Development of a new formulation of roflumilast for pulmonary drug delivery to treat inflammatory lung conditions.

The aim of this study was to develop roflumilast dry powder inhaler (DPI) formulations by spray drying using hydroxypropyl-ß-cyclodextrin (HPßCD) and to determine their suitability for pulmonary delivery. Different feed solution concentrations, solvent systems and spray drying parameters were used to obtain the formulations which were characterized using X-ray powder diffraction, thermal analysis, scanning electron microscopy, particle size distribution, bulk and tapped density, specific surface area, dynamic vapour sorption, in vitro deposition properties using a Next Generation Impactor (NGI) and transepithelial permeability. Microparticles spray dried from ethanol were wrinkled and amorphous, exhibiting high glass transition temperatures while those from methanol:n-butyl acetate consisted of irregularly shaped porous particles partially crystalline. All formulations presented low density, particle size and residual solvent content exhibiting high depositon in the lower stages of the NGI. Mass median aerodynamic diameters (MMADs) were in the range of 3.32-4.49 µm, with high fine particle fractions (FPF < 5 µm). Stability studies demonstrated no significant modifications in the solid-state nature and in the aerolisation performance of the selected formulation which presented a Papp of 8.73 × 10-6 ±â€¯4.70 × 10-7 cm/s. The developed roflumilast DPI formulations have potential therapeutic applications in the treatment of lung diseases.

Synthesis of conjugated bile acids/azastilbenes as potential antioxidant and photoprotective agents.

A series of 14 bile acids/azastilbenes conjugates (1a-g and 2a-g) was prepared through the condensation of bile amides (1 and 2) and aromatic aldehydes. The newly synthesized conjugates were evaluated in vitro for their antioxidant and photoprotective activities. Six compounds (1, 1a, 1b, 2, 2a and 2b) showed promising antioxidant activity with IC50 values of 19.60-31.83 µg mL(-1). The synthesized compounds presented a varied photoprotection profile, with the SPF ranging from 2 to 9. Among the 16 compounds tested for the protection against UVB sunrays, 3 compounds (2c, 2e and 2g) presented more significant protection than resveratrol and the free azastilbene 3; while the UVAPF increased from 2 in resveratrol and 5 in 3 to 5-11 in the majority of the conjugates.

Potential of the essential oil from Pimenta pseudocaryophyllus as an antimicrobial agent.

This study evaluated the effectiveness of the essential oil of Pimenta pseudocaryophyllus in inhibiting the growth of the main bacteria responsible for bad perspiration odor (Staphylococcus epidermidis, Proteus hauseri, Micrococcus yunnanensis and Corynebacterium xerosis). The chemical profile of the essential oil was evaluated by high-resolution gas chromatography (HR-GC) and four constituents were identified, eugenol being the major component (88.6%). The antimicrobial activity was evaluated by means of the turbidimetric method, using the microdilution assay. The minimum inhibitory concentration (MIC) values of the essential oil ranged from 500 to 1,000 µg mL⁻¹. Scanning electron microscope (SEM) observations confirmed the physical damage and morphological alteration of the test bacteria treated with the essential oil, reference drugs and eugenol. The findings of the study demonstrated that this essential oil can be used in the formulation of personal care products.

Stachytarpheta gesnerioides Cham: chemical composition of hexane fraction and essential oil, antioxidant and antimicrobial activities / Stachytarpheta gesnerioides Cham: composición química de la fracción hexánica y aceite esencial, actividades antioxidante y antimicrobiana

In the present study we investigated the chemical composition of hexane fraction and essential oil of Stachytarpheta gesnerioides (Verbenaceae) by GC-MS, total phenol and flavonoid contents. The antioxidant capacity and antimicrobial activity were investigated in five extracts of leaves of S. gesnerioides. Aqueous and 100 percent ethanol extracts were prepared by dynamic maceration. Hexane, ethyl acetate and methanol extracts were prepared by Soxhlet extraction. The essential oil (EO) and hexane fraction (HF) are mainly composed by guaiol. Moreover, the HF is also rich in the monoterpene alpha-pinene. The total phenol content ranged from 0.85 to 22.74 mg gallic acid equivalent /100mg dry extract at Folin–Ciocalteu’s reagent method. The total flavonoid concentration ranged from 0.68 to 13.65 mg rutin equivalent /100mg dry extract, detected using 8 percent aluminium chloride. The ethyl acetate extract (IC50=9.41 ug/ml) showed the highest antioxidant activity. The extracts were found to be effective to inhibit the microorganisms tested.

Se han investigado la composición química de la fracción hexánica (FH) y aceite esencial (AE) de Stachytarpheta gesnerioides (Verbenaceae) por GC-MS, el contenido de fenoles totales y flavonoides. La capacidad antioxidante y actividad antimicrobiana fueron investigadas en cinco extractos de hojas de S gesnerioides. Extractos acuosos y etanolico fueron preparados por la maceración dinámica y extracción continua en Soxhlet con hexano, acetato de etilo y metanol. Las fracciones AE y FH están compuestas principalmente por guaiol. La fracción FH es también rica en alfa-pineno. El contenido de fenoles totales varió desde 0,85 hasta 22,74 mg de ácido gálico/100 mg de extracto seco (Folin-Ciocalteu). La concentración total de flavonoides varió desde 0,68 hasta 13,65 mg en equivalentes de rutina/100 mg de extracto seco, que se detectó mediante reacción con cloruro de aluminio al 8 por ciento. El extracto de acetato de etilo (CI50=9,41 ug/ml) enseño la más grande actividad antioxidante. Los extractos se encontraron eficaces para inhibir los microorganismos ensayados.

In vitro inhibition of adhesion of Escherichia coli strains by Xylitol

The present study aimed to evaluate xylitol's antimicrobial and anti-adherence activities on Escherichia coli (ATCC 8739) and on another clinical strain enteropathogenic E. coli (EPEC). In vitro minimum inhibitory concentration (MIC) test and adhesion assays were performed using 0.5, 2.5 and 5.0 percent xylitol. It was found that xylitol did not have antimicrobial properties on these strains. The scanning electron microscopy (SEM) demonstrated that the slides treated with xylitol had a significant reduction in the number of bacilli and the inhibition of microbial adhesion was probably the xylitol's mechanism of action. Xylitol could be a possible alternative on the control of E. coli infections.