RE:Different models for different age groups? Infinite objective functions

From: "Gobburu, Jogarao V" <GOBBURUJ@cder.fda.gov> Subject: RE:Different models for different age groups? Infinite objective functions Date: Wed, 18 Jul 2001 12:42:05 -0400 Dear Jim, 1. To a large extent, the approach depends on what you want to do with the so developed model. You might want to comine data from adults and pediatrics and then analyze. 2. You might also want to consider the use of allometric models for body weight - CL(and Q) relationship. Further, there is evidence in literature that age is an important parameter to describe the organ maturation process. In general, liver and kidney reach comparable capacity to adults (after body size adjustment) at about 2 years. Hence you might want to use an Emax or a constant rate infusion type model (see below for a ref) to describe the maturation process. Anderson BJ, Woollard GA, Holford NH. A model for size and age changes in the pharmacokinetics of paracetamol in neonates, infants and children. Br J Clin Pharmacol. 2000 Aug;50(2):125-34. Joga Gobburu, Pharmacometrics, CDER, FDA