negative objective value

From: "Jiao Zheng" <jiaozhen@online.sh.cn> Subject: negative objective value Date: Tue, 17 Apr 2001 07:34:22 +0800 Dear All: I am a new user in NONMEM and trying to model parent compound and metabolite seperately. I only got negative objective value in my metabolite modeling. I would be interested in why on how to take this problem. My situation is: mutiple-trough sampling design one compartemnt open kinetic model with first order absorption and elimination in both parent and metabolite drug according to reference (ADVAN 2 TRANS 2) Ka was fixed to 0.05 from the parent drug's mean value of K. thanks in advance Jiao Zhen Clin Pharm Dept. Hua Shan Hosptial Shanghai, P.R.China