Evaluation of Transdermal Drug Permeation as Modulated by Lipoderm and Pluronic Lecithin Organogel

The transdermal delivery of 2 fluorescent probes with similar molecular weight but different lipophilicity, into and through the skin from 2 commercially available transdermal bases, pluronic lecithin organogel, and Lipoderm^® has been evaluated. First, in vitro penetration of fluorescein sodium and fluorescein (free acid) through porcine skin was evaluated. Retention and depth distribution profiles in skin were obtained by tape stripping and then followed by optical sectioning using multiphoton microscopy. The results showed that Lipoderm^® led to an enhanced penetration of the hydrophilic compound, fluorescein sodium. For the lipophilic compound fluorescein (free acid), Lipoderm^® performed similar to pluronic lecithin organogel base, where minimal drug was detected in either receptor phase. The skin retention and depth distribution results also showed that the hydrophilic fluorescein sodium had high skin retention with Lipoderm^®, whereas fluorescein (free acid) had very low penetration and retention with increasing skin depth. Moreover, optical sectioning by multiphoton microscopy revealed an uneven distribution of probes across the skin in the x-y plane for both transdermal bases. This work showed that a hydrophilic compound has significantly increased skin penetration and retention when formulated with Lipoderm^®, and the skin retention of the probe was the main determinant of its skin flux.     

Intradermal Delivery of a Near-Infrared Photosensitizer Using Dissolving Microneedle Arrays

Nodular basal cell carcinoma is a deep skin lesion and one of the most common cancers. Conventional photodynamic therapy is limited to treatment of superficial skin lesions. The parenteral administration of near-IR preformed photosensitizers suffers from poor selectivity and may result in prolonged skin photosensitivity. Microneedles (MNs) can provide localized drug delivery to skin lesions. Intradermal delivery of the preformed near-IR photosensitizer; 5,10,15,20-tetrakis(2,6-difluoro-3-N-methylsulfamoylphenyl bacteriochlorin (Redaporfin?) using dissolving MN was successful in vitro and in vivo. MN demonstrated complete dissolution 30 min after skin application and showed sufficient mechanical strength to penetrate the skin to a depth of 450 μm. In vitro deposition studies illustrated that the drug was delivered and detected down to 5 mm in skin. In vivo biodistribution studies in athymic nude mice Crl:NU(NCr)-Foxn1^nu showed both fast initial release and localized drug delivery. The MN-treated mice showed a progressive decrease in the fluorescence intensity at the application site over the 7-day experiment period, with the highest and lowest fluorescence intensities measured being 9.2 × 10¹⁰ ± 2.5 × 10¹⁰ and 3.8 × 10⁹ ± 1.6 × 10⁹ p/s, respectively. By day 7, there was some migration of fluorescence away from the site of initial MN application. However, the majority of the body surfaces showed fluorescence levels that were comparable to those seen in the negative control group. This work suggests utility for polymeric MN arrays in minimally invasive intradermal delivery to enhance photodynamic therapy of deep skin lesions.     

Preclinical Development of Cell-Based Products: a European Regulatory Science Perspective

Purpose

This article describes preclinical development of cell-based medicinal products for European markets and discusses European regulatory mechanisms open to developers to aid successful product development. Cell-based medicinal products are diverse, including cells that are autologous or allogeneic, have been genetically modified, or not, or expanded ex vivo, and applied systemically or to an anatomical site different to that of their origin; comments applicable to one product may not be applicable to others, so bespoke development is needed, for all elements - quality, preclinical and clinical.

Methods

After establishing how the product is produced, proof of potential for therapeutic efficacy, and then safety, of the product need to be determined. This includes understanding biodistribution, persistence and toxicity, including potential for malignant transformation. These elements need to be considered in the context of the intended clinical development.

Results

This article describes regulatory mechanisms available to developers to support product development that aim to resolve scientific issues prior to marketing authorization application, to enable patients to have faster access to the product than would otherwise be the case.

Conclusions

Developers are encouraged to be aware of both the scientific issues and regulatory mechanisms to ensure patients can be supplied with these products.

     

Empirical treatment of lower urinary tract infections in the face of spreading multidrug resistance: in vitro study on the effectiveness of nitroxoline

The spread of antimicrobial resistance challenges the empirical treatment of urinary tract infections (UTIs). Among others, nitrofurantoin is recommended for first-line treatment, but acceptance among clinicians is limited due to chronic nitrofurantoin-induced lung toxicity and insufficient coverage of Enterobacteriaceae other than Escherichia coli. Nitroxoline appears to be an alternative to nitrofurantoin owing to its favourable safety profile, however data on its current in vitro susceptibility are sparse. In this study, susceptibility to nitroxoline was tested against 3012 urinary clinical isolates (including multidrug-resistant bacteria and Candida spp.) by disk diffusion test and/or broth microdilution. At least 91% of all Gram-negatives (n?=?2000), Gram-positives (n?=?403) and yeasts (n?=?132) had inhibition zone diameters for nitroxoline ≥18?mm. Except for Pseudomonas aeruginosa, nitroxoline MIC₉₀ values were ≤16?mg/L and were 2- to >16-fold lower compared with nitrofurantoin. In extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae and methicillin-resistant Staphylococcus aureus (MRSA), MIC₉₀ values of nitroxoline were two-fold higher compared with non-ESBL-producing enterobacteria and methicillin-susceptible S. aureus (MSSA). The in vitro efficacies of nitroxoline and nitrofurantoin against ATCC strains of E. coli, Enterococcus faecalis and Proteus mirabilis were compared by time–kill curves in Mueller–Hinton broth and artificial urine. Nitroxoline was non-inferior against E. coli, P. mirabilis and E. faecalis in artificial urine. In conclusion, nitroxoline showed a broad antimicrobial spectrum, with inhibition zone diameters and MICs of nitroxoline well below the EUCAST breakpoint for E. coli for most organisms, and thus may also be a target for therapy of uncomplicated UTIs.     

Effects of high-dose baclofen on cue reactivity in alcohol dependence: A randomized,placebo-controlled pharmaco-fMRI study

Increased functional brain response towards alcohol-associated stimuli is a neural hallmark of alcohol dependence and a promising target for pharmacotherapy. For the first time, we assessed the effects of individually titrated high-dose baclofen on cue reactivity and functional connectivity in alcohol-dependent (AD) patients in a randomized controlled trial (RCT).We investigated 23 recently detoxified AD patients and 23 matched healthy controls (HC) with a cue reactivity functional magnetic resonance imaging task. Patients were further scanned at baseline without medication and during treatment with high-dose baclofen/placebo (30–270 mg/d). Analyses were conducted for alcohol cue-elicited brain response, alcohol cue-modulated and stimulus-independent functional connectivity with left ventral tegmental area (VTA) as seed region.At baseline, AD patients (N?=?23) showed increased cue-elicited brain activation in the ventral striatum (VS) compared to HC (N?=?23), which was decreased at the second scanning session compared to baseline. Patients receiving baclofen (N?=?10) showed a significant stronger decrease in cue-elicited brain activation in left orbitofrontal cortex (OFC), bilateral amygdala and left VTA than patients receiving placebo (N?=?13). Treatment with baclofen further led to a decrease in alcohol cue-modulated functional connectivity between left VTA and left anterior cingulate cortex (ACC) as well as left medial prefrontal cortex (MPFC). Regarding clinical outcome, significantly more patients of the baclofen group remained abstinent during the high-dose period.Baclofen specifically decreased cue-elicited brain responses in areas known to be involved in the processing of salient (appetitive and aversive) stimuli. Treatment with high-dose baclofen seems to provide a pharmacological relief of this neural “warning signal” evoked by alcohol-related cues, thereby possibly supporting patients in remaining abstinent.Trial Registration Identifier of the main trial [BACLAD study] at clinicaltrials.gov: NCT01266655.     

Extracellular vesicles released in response to respiratory exposures: implications for chronic disease

Extracellular vesicles (EV) are secreted signaling entities that enhance various pathological processes when released in response to cellular stresses. Respiratory exposures such as cigarette smoke and air pollution exert cellular stresses and are associated with an increased risk of several chronic diseases. The aim of this review was to examine the evidence that modifications in EV contribute to respiratory exposure-associated diseases. Publications were searched using PubMed and Google Scholar with the search terms (cigarette smoke OR tobacco smoke OR air pollution OR particulate matter) AND (extracellular vesicles OR exosomes OR microvesicles OR microparticles OR ectosomes). All original research articles were included and reviewed. Fifty articles were identified, most of which investigated the effect of respiratory exposures on EV release in vitro (25) and/or on circulating EV in human plasma (24). The majority of studies based their main observations on the relatively insensitive scatter-based flow cytometry of EV (29). EV induced by respiratory exposures were found to modulate inflammation (19), thrombosis (13), endothelial dysfunction (11), tissue remodeling (6), and angiogenesis (3). By influencing these processes, EV may play a key role in the development of cardiovascular diseases and chronic obstructive pulmonary disease and possibly lung cancer and allergic asthma. The current findings warrant additional research with improved methodologies to evaluate the contribution of respiratory exposure-induced EV to disease etiology, as well as their potential as biomarkers of exposure or risk and as novel targets for preventive or therapeutic strategies.