Godfrey K R, Jones R P, Brown R F
J Pharmacokinet Biopharm. 1980 Dec;8(6):633-48. doi: 10.1007/BF01060058.
Single input, single output experiments can result in nonunique solutions for the rate constants to a linear compartmental model used to describe the pharmacokinetics. Where a finite number of solutions exists, a priori knowledge has to be used to distinguish between the solutions. Where there is a infinite number of solutions, assumptions have to be made about the values of some rate constants in order to obtained a unique solution for the other. This paper considers such experiments and determines whether either the addition of an extra input (simultaneously with the first input) or the taking of an extra measurement would result in a unique solution. It is found that perturbing a second input can be useful, but only if the perturbation is of different shape from the first input. Measurements of drug in urine and metabolite in plasma are generally not helpful in resolving identifiability of the drug dynamic model. If a radioactive tracer is used, through, the second measurement (for example, by externally scanning the radioactivity of the liver) can prove useful, but only if the gain of the measuring device is known.
单输入、单输出实验可能会导致用于描述药代动力学的线性房室模型的速率常数出现非唯一解。在存在有限数量解的情况下，必须利用先验知识来区分这些解。在存在无限数量解的情况下，则必须对某些速率常数的值做出假设，以便为其他常数获得唯一解。本文考虑了此类实验，并确定额外输入（与第一个输入同时进行）或进行额外测量是否会得到唯一解。结果发现，扰动第二个输入可能会有用，但前提是该扰动的形状与第一个输入不同。尿液中的药物和血浆中的代谢物测量通常无助于解决药物动力学模型的可识别性问题。不过，如果使用放射性示踪剂，第二次测量（例如，通过外部扫描肝脏的放射性）可能会有用，但前提是测量设备的增益已知。
