Field trials critical phase

Application of the test substance to the test system is without doubt the most critical step of the residue field trial. Under-application may be corrected, if possible and if approved by the Study Director, by making a follow-up application if the error becomes known shortly after the application has been made. Over-application errors can usually only be corrected by starting the trial again. The Study Director must be contacted as soon as an error of this nature is detected. Immediate communication allows for the most feasible options to be considered in resolving the error. If application errors are not detected at the time of the application, the samples from such a trial can easily become the source of undesirable variability when the final analysis results are known. Because the application is critical, the PI must calculate and verify the data that will constitute the application information for the trial. If the test substance weight, the spray volume, the delivery rate, the size of the plot, and the travel speed for the application are carefully determined and then validated prior to the application, problems will seldom arise. With the advent of new tools such as computers and hand-held calculators, the errors traditionally associated with applications to small plot trials should be minimized in the future. The following paragraphs outline some of the important considerations for each of the phases of the application. 

The form or format of the notebook is not as critical from a GLP compliance standpoint as the completion of the record in an accurate, timely, readable, and attributable manner. Company and PI conventions typically have evolved into cost-effective and very efficient data notebooks for field residue trials. These notebooks contain the actual raw data for the trial and once begun become extremely valuable legal parts of the study record. The notebooks should be audited by QA during the field phase of the study as well as at the end of the trial before the notebook is returned to the sponsor organization. The quality of the trial is easily refiected in the quality of the field notebook at the end of the season. 

The book concludes with Part 6 dealing with several new developments in the field of antitumor Pt compounds. Farrell et al. present novel di- and trinuclear Pt11 compounds which display marked antitumor activity and, at the same time, have DNA-binding properties different from those of cis-platin. Kelland describes orally active PtIV drugs presently in Phase-I and Phase-II clinical trials. New and fast mechanism-based methods for screening Pt compounds for potential antitumor activity are the topic of the chapter by Sandman and Lippard. Finally, Kozelka critically examines the contribution that computational studies can make to the field of Pt-nucleic acid interactions. He ends with an optimistic outlook for using ab initio molecular-dynamics calculations in the near future. 

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