Innovative in Vitro Method To Predict Rate and Extent of Drug Delivery to the Brain across the Blood–Brain Barrier

Abstract

The relevant parameters for predicting rate and extent of access across the blood-brain barrier (BBB) are fu,plasma (unbound fraction in plasma), Vu,brain (distribution volume in brain) and Kp,uu,brain (ratio of free concentrations in plasma and brain). Their estimation still requires animal studies and in vitro low throughput experiments which make difficult the screening of new CNS candidates. The aim of the present work was to develop a new whole in vitro high throughput method to predict drug rate and extent of access across the BBB. The system permits estimation of fu,plasma, Vu,brain and Kp,uu,brain in a single experimental system, using in vitro cell monolayers in different conditions. From the ratios of the apparent permeability values (Papp) with the adequate mathematical analysis the relevant parameters can be estimated. Papp of ten model compounds has been obtained in MDCKII and MDCK-Mdr1cell monolayers in the absence and presence of albumin and brain homogenate. The ratio of Papp in the absence and presence of albumin allows estimation of in vitro fu,plasma. Papp in the presence of brain homogenate is used to estimate fu,brain and Vu,brain. Kp,uu,brain is estimated from the apical to basal versus basal to apical clearances. The BBB parameters obtained with the new method were predictive of the in vivo behavior of candidates. In vitro fu,plasma, Kp,uu,brain and Vu,brain (calculated with Papp from MDCKII cell line) presented a good correlation with in vivo fu,plasma, Kp,uu,CSF and Vu,brain published values (r=0.92; r=0.85; and r=0.99 respectively). Despite its simplicity the predictive performance is fairly good considering the reduced number of tested compounds with different physicochemical and transport properties. Further experimental modifications could be checked to optimize the method, but the present data support its feasibility. As other in vitro cell culture models, the system is suitable for miniaturization and robotization to allow high throughput screening of CNS candidates.

The hunt for brain Aβ oligomers by peripherally circulating multi-functional nanoparticles: Potential therapeutic approach for Alzheimer disease

“…The better performance of mApoE-PA-LIP with respect to other LIP is likely due to their higher binding affinity to Aβo. 6 The effect of mApoE-PA-LIP on Aβo brain efflux was also evaluated under conditions simulating the different protein concentration in blood 29 and CSF. 30 Also under these conditions, an increase of Aβ EP was detected, even in a lesser extent, probably due to the formation of the so called 'protein corona', that might influence the mApoE-PA-LIP performance.…”

“…The effect of mApoE-PA-LIP on Aβo brain efflux was also evaluated under conditions simulating the protein concentration in blood 29 and CSF, 30 that are the presence of 4% BSA (w/v) in the apical compartment ('blood' side) and 0.015% BSA (w/v) in the basolateral one ('brain' side). The results ( Figure 6) showed that also in these experimental conditions the basolateral-toapical passage of Aβo was higher in the presence of mApoE-PA-LIP (EP = 4.30 ± 0.3 × 10 -5 cm/min) in the apical compartment than in their absence (EP = 2.89 ± 0.2 × 10 -5 cm/min).…”

Miniaturization and Automation of a Human In Vitro Blood–Brain Barrier Model for the High-Throughput Screening of Compounds in the Early Stage of Drug Discovery

“…Nevertheless, the hurdle of NP passage across the BBB, as well as the pharmacological and toxicological aspects of these nanomedicines [ 14 ], must be deeply studied in the early stages of drug discovery in order to reduce the risk of costly later failures in the clinical phases. Therefore, reliable methods for selecting the best candidates in the early preclinical phases are urgently needed [ 15 ]. However, the new drug and therapeutic strategy screenings are also very expensive and time-consuming, where in vivo screening remains applied at the preclinical testing stage.…”

Intestinal Permeability Study of Clinically Relevant Formulations of Silibinin in Caco-2 Cell Monolayers

“…Indeed, responses to Eurosil 85 /Euromed-based therapy were notable in the central nervous system, where highly significant clinical and radiological improvements of brain metastases (including several complete responses) were achieved in patients with non-small cell—lung cancer [44,45]. According to our results, the silibinin formulation exhibiting the highest permeability rate (i.e., Eurosil 85 /Euromed) was predicted to also exhibit a passive diffusion mechanism of transport [46,47]. Because some nutritional modalities are known to impact intestinal permeability, it might be relevant to evaluate how certain dietary approaches with proposed applications in oncology (e.g., high-fat, low-carbohydrate ketogenic diets, [48] might represent a potentially promising strategy to increase biodisponibility and the efficacy of silibinin-based anti-cancer strategies.…”