Pharmacokinetics preparation assessment

USAF. 1990. U.S. Air Force. Development and validation of methods for applying pharmacokinetic data in risk assessment. Volume 1 Executive summary/introduction. Prepared by Clement International Corp., Ruston LA. (K.S. Crump Div.). NTIS/AD-A237 365/2. 

Risk assessment. The model was designed to simulate the pharmacokinetics of selenium orally administered as selenite to humans as a preparation for a larger anticancer supplementation study jointly undertaken by the National Cancer Institute (NCI) and the U.S. Department of Agriculture (USDA) (Patterson and Zech 1992 Patterson et al. 1991,1993). 

Due to their complex composition the pharmacokinetic assessment of herbal medications generally imposes serious technical and regulatory problems. As the active principle(s) of plant extracts are often not known it is difficult to decide which constituent(s) should actually be studied [218]. In the absence of a well defined therapeutically relevant chemical entity, characteristic constituents of herbal preparations are frequently employed for the purpose of standardization. Correspondingly, pharmacokinetic evaluations of Hypericum extracts have almost exclusively been based on the analysis of the naphthodianthrones hypericin 1 and pseudohypericin 2 which represent typical products of members of the genus Hypericum and are considered to be involved in some of their clinical effects. 

Single-dose pharmacokinetic studies may provide sufficient information for dosage selection in medicinal product that exhibit linear pharmacokinetics. Medicinal products that exhibit non-linearity in absorption, distribution and elimination may require steady-state studies. Such an approach has been used to assess the pharmacokinetics of an extemporaneously prepared sotalol syrup formulation in neonates, infants, and younger and older children. Scheduled blood samples were taken over a 36-hour time interval following dose administration (Saul et al, 2001). 

Pharmaceutical companies, hospital and community pharmacies prepare medicines. Although batch sizes vary greatly, the underlying principles of product development are comparable and driven by physical chemistry, physiology and pharmacokinetics. When the medication is meant for only a small group of patients or even for individual use, these principles cannot be fully elaborated and formulation becomes more and more based on risk assessment. 

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