Flurbiprofen, a nonsteroidal antiinflammatory drug (NSAID), has been recently described to selectively inhibit beta-amyloid(1)(-)(42) (Abeta42) secretion, the most toxic component of the senile plaques present in the brain of Alzheimer patients. The use of this NSAID in Alzheimer's disease (AD) is hampered by a significant gastrointestinal toxicity associated with cyclooxygenase (COX) inhibition. New flurbiprofen analogues were synthesized, with the aim of increasing Abeta42 inhibitory potency while removing anti-COX activity. In vitro ADME developability parameters were taken into account in order to identify optimized compounds at an early stage of the project. Appropriate substitution patterns at the alpha position of flurbiprofen allowed for the complete removal of anti-COX activity, while modifications at the terminal phenyl ring resulted in increased inhibitory potency on Abeta42 secretion. In rats, some of the compounds appeared to be well absorbed after oral administration and to penetrate into the central nervous system. Studies in a transgenic mice model of AD showed that selected compounds significantly decreased plasma Abeta42 concentrations. These new flurbiprofen analogues represent potential drug candidates to be developed for the treatment of AD.

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Recently, mesenchymal stromal stem cells (MSCs) have been proposed as therapeutic agents because of their promising preclinical features and good safety profile. However, their introduction into clinical practice has been associated with a suboptimal therapeutic profile. In this review, we address the biodistribution of MSCs in preclinical studies with a focus on the current understanding of the pharmacodynamics (PD) and pharmacokinetics (PK) of MSCs as key aspects to overcome unsatisfactory clinical benefits of MSC application. Beginning with evidence of MSC biodistribution and highlighting PK and PD factors, a new PK-PD model is also proposed. According to this theory, MSCs and their released factors are key players in PK, and the efficacy biomarkers are considered relevant for PD in more predictive preclinical investigations. Accounting for the PK-PD relationship in MSC translational research and proposing new models combined with better biodistribution studies could allow realization of the promise of more robust MSC clinical translation.

Organic cation transporters (OCT1-3) mediate the transport of organic cations including inhaled drugs across the cell membrane, although their role in lung epithelium hasn't been well understood yet. We address here the expression and functional activity of OCT1-3 in human airway epithelial cells A549, Calu-3 and NCl-H441. Kinetic and inhibition analyses, employing [(3)H]1-methyl-4-phenylpyridinium (MPP+) as substrate, and the compounds quinidine, prostaglandine E2 (PGE2) and corticosterone as preferential inhibitors of OCT1, OCT2, and OCT3, respectively, have been performed. A549 cells present a robust MPP+ uptake mediated by one high-affinity component (Km~50μM) which is identifiable with OCT3. Corticosterone, indeed, completely inhibits MPP+ transport, while quinidine and PGE2 are inactive and SLC22A3/OCT3 silencing with siRNA markedly lowers MPP+ uptake. Conversely, Calu-3 exhibits both a high (Km<20μM) and a low affinity (Km>0.6mM) transport components, referable to OCT3 and OCT1, respectively, as demonstrated by the inhibition analysis performed at proper substrate concentrations and confirmed by the use of specific siRNA. These transporters are active also when cells are grown under air-liquid interface (ALI) conditions. Only a very modest saturable MPP+ uptake is measurable in NCl-H441 cells and the inhibitory effect of quinidine points to OCT1 as the subtype functionally involved in this model. Finally, the characterization of MPP+ transport in human bronchial BEAS-2B cells suggests that OCT1 and OCT3 are operative. These findings could help to identify in vitro models to be employed for studies concerning the specific involvement of each transporter in drug transportation.