Additional study designs

Other appealing design features in new drug development include those that allow for monitoring of data while the trial is ongoing, and those that permit adaptations during a trial. 

Analyses conducted during a study are called interim analyses. Common uses of interim analyses are as follows  

A number of methodologies are available to assist in the quantification of evidence (accounting for type 1 and 11 errors) that enable 

Chapter 1 2 Additional statistical considerations in clinical trials 

What are some advantages and disadvantages of using multiple investigational centers in clinical trials  

---

Additional study designs (Figure 4d and e) are essentially combinations of the first two or three designs. 

The absorption, distribution, metabolism, and excretion of 2-butoxyethanol are relatively well understood, leading to a number of PBPK models (Corley 1996 Corley et al. 1994 Johanson 1986, 1991a Johanson and Naslund 1988 Shyr et al. 1993). Tliese models have been validated with acute- and intermediate-duration pharmacokinetic data. Chronic pharmacokinetic data would be useful so that the models could be validated for chronic exposure. Additional studies designed to define the differences and similarities between 2-butoxyethanol and its acetate with regard to absorption, distribution, metabolism, and excretion would be useful to establish these parameters for to 2-butoxyethanol acetate. 

Animals Althouth several mammalian test species may be used for the test, the rat is preferred. When attempting to estimate hazards to young humans, additional studies designed to consider the developmental stage of the test animal in relation to anticipated human exposure should be performed. 

Therefore, additional studies designed to assess the toxicokinetic properties of zinc following inhalation and dermal exposures would be useful. 

This report provides an aging assessment of electric motors and was conducted under the auspices of the USNRC NPAR. Pertinent failure-related information was derived from LERs, IPRDS, NPRDS, and NPE including failure modes, mechanisms, and causes for motor problems. In addition, motor design and materials of construction were reviewed to identify age-sensitive components. The study included consideration of the seismic susceptibility of age-degraded motor components to externally-induced vibrational effects. 

Since in vivo tests in exposed human populations would involve concomitant exposure to other toxicants, it would be difficult to assess the genotoxic potential of methyl parathion alone. Therefore, additional well-designed in vitro studies using human cell lines are needed to determine the effects of methyl parathion on various genotoxic parameters (e.g., sister chromatid exchange, chromosomal aberrations, unscheduled DNA synthesis). 

In a study designed to test the feasibility of a germanium aza Brook rearrangement, the /V-benzyl derivative 25 of amine 24 was treated with BuLi13. After subsequent addition of water, the hydride 28 was obtained as the sole Ge-containing product (Scheme 11). 

---