An automated process for building reliable and optimal in vitro/in vivo correlation models based on Monte Carlo simulations

Use of Time-Domain NMR for 1H T1 Relaxation Measurement and Fitting Analysis in Homogeneity Evaluation of Amorphous Solid Dispersion

This study examined the usefulness of 1H T1 relaxation measurements for evaluating the homogeneity of amorphous solid dispersion (ASD). Indomethacin and polyvinylpyrrolidone were used to prepare two kinds of ASDs. One was inhomogeneous ASD (ASDmelt) prepared by a melt-quenching method, and the other was homogeneous ASD (ASDsolvent) prepared by a solvent evaporation method. The T1 relaxation was measured by the time-domain NMR (TD-NMR) technique using a low-field NMR system. Curve-fitting analysis of T1 relaxation plots was conducted using the Akaike information criterion. This fitting analysis revealed that the T1 relaxation of ASDmelt and ASDsolvent was biphasic and monophasic, respectively. ASDmelt and ASDsolvent were inhomogeneous and homogeneous on a nanometer scale, respectively, considering the spin diffusion of 1H nuclei. These T1 results were consistent with the Raman mapping of ASDs. From the fitting analysis of 1H T1 relaxation, we conclude that TD-NMR is a promising technique for evaluating ASD homogeneity.

System-based Approach to Prediction of Surfactants’ Influences on Pharmaco-kinetics and Pharmacodynamics

The paper presents a system-based approach for predicting the changes of the plasma concentration and the therapeutic effect of sodium p-aminosalicylate caused by addition of surfactant Tween 80 to a liquid dosage form. A predictive pharmacokinetic model of the oral administration is synthetized together with the corresponding model of its parametric sensitivity. The sensitivities predicted by the model are then compared to those obtained from the in-vi vo experiment. The close correspondence between them is used to prove the model correctness. Similarly the Emax model of the therapeutic effect predicts influences of the added surfactants on the therapeutic effect. In this context, the problem of determining an optimal absorption rate for the desired time course of the therapeutic effect is solved. As a by-product this study, it is shown that the (in-silico generated) sensitivity of plasma concentration to the drug absorption rate may provide information on how far the in-silico experiment can serve as a substitute for in-vivo bioavailability and bioequivalence studies

Pharmacokinetics in drug discovery

The aim of this current review is to summarize the present status of pharmacokinetics in Drug Discovery. The review is structured into four sections. The first section is a general overview of what we understand by pharmacokinetics and the different LADMET aspects: Liberation, Absorption, Distribution, Metabolism, Excretion, and Toxicity. The second section highlights the different computational or in silico approaches to estimate/predict one or several aspects of the pharmacokinetic profile of a discovery lead compound. The third section discusses the most commonly used in vitro methodologies. The fourth and last section examines the various approaches employed towards the pharmacokinetic assessment of discovery molecules; including all the LADME processes, discussing the different mathematical methodologies available to establish the PK profile of a test compound; what the main differences are and what should be the criteria for using one or another mathematical approach. The major conclusion of this review is that the use of the appropriate preclinical assays has a key role in the long-term viability of a pharmaceutical company since applying the right tools early in discovery will play a key role in determining the company's ability to discover novel safe and effective therapeutics to patients as quickly as possible.