Combinatorial Chemistry & High Throughput Screening - Volume 13, Issue 2, 2010

The nomination of a lead discovery molecule to a viable drug candidate is a key step in the drug discovery/development continuum. Transition through this critical milestone requires the knowledge of the pharmacological action as well as insights into the absorption, distribution, metabolism, excretion and toxicity (ADMET) profile of the compound. The current motivation to balance the pharmacological attributes Read More

Physicochemical properties of drug molecules impact many aspects of both in vivo and in vitro behavior. Poor physicochemical properties can often create a significant impediment to establishing reliable SAR, establishing proof of principle type studies using in vivo models, and eventually leading to added performance variability and costs throughout the development life cycle; in the worst case scenario, even preventing executio Read More

Solubility and cellular permeability are two of the most important biopharmaceutical properties impacting the successful development of drug substances. Given the importance of these properties, most pharmaceutical companies have invested in medium to high throughput technologies for early evaluation of these characteristics in the drug discovery funnel in order to select, prioritize or eliminate compounds with unfav Read More

Drug transporters play an important role in the absorption, distribution, excretion and toxicity of both endogenous and exogenous compounds. Transporters may act as physiological ‘gatekeepers’ in the regulation of the pharmacological and/or toxicological effects of drugs by limiting distribution to tissues responsible for their effect and/or toxicity. This review will first provide a brief outline of the characteristics of mem Read More

Drug metabolizing enzyme induction, or the process of generating excess drug metabolizing enzyme in important tissues of drug disposition such as liver and intestine, can give rise to pharmacokinetic situations whereby drug interactions occur. There are two major concerns associated with enzyme induction. First is the potential loss of efficacy due to more rapid metabolism and second is the risk of an increase in the formati Read More

Advances in drug interaction screening have resulted in reduced compound attrition rates due to unfavorable CYP-mediated drug interactions in clinical trials and improved patient safety. A major driver for the success in predicting drug interactions is a better understanding of the biological, chemical or mechanical factors that can impact the prediction of drug interactions in vitro. The enzyme source, probe substrate, access Read More

In this review, the current approach to predicting hepatic clearance from in vitro metabolic systems is discussed along with a survey of current industry practice. The definitive method of determining intrinsic clearance remains the measurement of Michaelis-Menten parameters derived from metabolite formation rate data. However, in drug discovery this method has limitations which result in the method most commonly Read More

This review describes methods for quantifying the binding of small molecule drug candidates to plasma proteins and the application of these methods in drug discovery and development. Particular attention is devoted to methods amenable to medium-to-high throughput analysis and those well suited for measurement of compounds that are highly protein bound. The methods reviewed herein include the conventional Read More

One of the greatest challenges facing the pharmaceutical industry today is the failure of promising new drug candidates due to unanticipated adverse effects discovered during preclinical animal safety studies and clinical trials. Late stage attrition increases the time required to bring a new drug to market, inflates development costs, and represents a major source of inefficiency in the drug discovery/development process. It Read More

A goal of preclinical discovery is the identification of drug candidates suitable for clinical testing. Successful integration of in vitro and in vivo experimental data sets can afford projections of human dose regimens anticipated to be safe and therapeutically beneficial. While in vitro experiments guide new chemical syntheses and are essential to understanding drug action and disposition, in vivo characterizations pro Read More

Larry C. Wienkers is currently the Executive Director for the Department of Pharmacokinetics and Drug Metabolism at Amgen in Seattle, WA. Larry's areas of scientific interest include: understanding of the mechanisms of cytochrome P450 oxidation reactions; the application of novel in vitro metabolism techniques to understand the enzymatic basis for biotransformation of potential therapeutic agents at the drug discov Read More