Clinical studies, phase metabolism

In pharmaceutical and medical device development, clinical trials are classified into four main phases designated with Roman numerals 1,11, III and lY The various phases of development trials differ in purpose, length and number of subjects involved. Phase I trials are conducted to determine safe dose levels of a medication, treatment or product (National Institutes of Health, 2002). The main purpose is often to determine an acceptable single dosage - how much can be given without causing serious side-effects. Phase I trials will also involve studies of metabolism and bioavailabity (Pocock, 1983). The sample size of a Phase 1 clinical trial is usually small, ranging from 10-80 subjects (National Institutes of Health, 2002 Pocock, 1983). 

These five dimensions, along with the FDA Center target of the application (Metabolic, CNS, Oncology, etc.) the proposed study phases 1 (preclinical), 2 (limited clinical), 3 (extensive clinical), and 4 (postmarketing) and the details of the proposed study design are used to classify the IND and its intent. 

He took over the responsibility for the complete Drug Metabolism and Pharmacokinetics Department in Frankfurt in 2000. His activities ranged from in-silico approaches at very early stages of the value chain, in-vitro studies, and in vivo animal studies up to Phase I, II and III clinical studies. The whole scope of these activities... 

Seventy-five percent of drug candidates do not reach the clinical trial phase mainly due to poor pharmacokinetics in animal studies (1). Since so many compounds fail in late stage testing, the current trend is to study the pharmacokinetics of lead compounds as early as possible. One of the most important elements of pharmacokinetics is lipophilicity, or a compound s affinity for fat. Usually, the more water soluble a compound is, the lower its lipophilicity. Low water solubility (high-lipophilicity) compounds have a limited oral bioavailability but are usually easily metabolized. On the other hand, low-lipophilicity compounds have poor membrane permeability since membranes are partly composed of fat. 

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